Why does condensation form on plastic windows in winter?

The appearance of condensation on windows should not be ignored. This process signals many factors that will need to be removed.
What to do if your PVC windows get wet or leak a lot, how to solve this problem - adjust, lubricate the mechanism, treat the glass or install ventilation?

To properly correct the situation, you need to know the main causes of condensation and methods for eliminating it.

Why does condensation appear on windows?

People who have wooden window frames often complain that condensation appears only on a new PVC window.
This is explained by the fact that wood fibers allow water vapor to pass through better. Often old frames were covered with invisible microcracks, from which a draft blew in in winter. The room could become very cold, but constant air circulation prevented excess humidity from accumulating. PVC glazing is completely sealed, so dampness simply has nowhere to go. The main reasons for condensation settling on windows are:

high humidity;
impaired convection;
disrupted microclimate;
problems with the glass unit or its assembly;
incorrect installation;
manufacturing defects.

Let's look at them in order.

Modern plastic windows are free from most of the shortcomings of their wooden predecessors. They protect from cold, street dampness, wind and noise. They do not require regular tinting or sealing with paper strips. When installing security fittings, the degree of burglary resistance increases. However, one common problem with wooden and PVC structures remains: condensation still often appears on them.

Mold is a companion of foggy windows, what to do about it

Mold must be dealt with immediately

One of the most unpleasant consequences of frost on windows is mold. If you do not pay attention to the formation of condensation and start the problem, this can lead to more serious consequences, or rather, fungus and mold. And what to do when the slopes are covered with mold?

When you notice the appearance of black spots around the windows, you should take care of removing this plaque. To do this, you can use various chemical compounds, including bleach or an alcohol solution. After removing plaque, you need to make it a rule to regularly ventilate the room. Such precautions are taken only in winter.

With the onset of warmer weather, it is necessary to take more serious measures and completely remove mold-affected areas of plaster and replace it with new one. After the new layer has dried, it must be treated with an antiseptic.

What is condensate

Condensation is moisture that forms on PVC windows. It looks like fog or fog on the glass. When there is a lot of it, individual drops roll down under the influence of gravity and merge with each other, leading to the appearance of entire streams.

Air always contains water vapor. Its amount varies depending on the temperature: the warmer it is, the more water can be in a gaseous state. When the temperature drops, excess moisture falls on surfaces in the form of small droplets.

During the cold season, the temperature outside is lower than inside the apartment. Because of this, the windows cool down, the air next to them also becomes colder, and therefore it cannot retain the absorbed steam, and it turns into liquid form - condensation.

Plastic windows leak when it rains

If it happens that during rain water flows through plastic windows, and you don’t know what to do. Don’t rush to panic, we will help you fix this problem and tell you why moisture is getting in.

Reasons for window leaks:

Installation errors. Most likely, even when installing the window, the technology of insulation and sealing of seams was violated and because of this the plastic window is leaking.
The seal has lost its properties, has become depleted, and has dried out. But this only happens if the sealing rubber has been in use for a long time.
Incorrectly made slopes.
There is a small amount of foam in the openings or it is of poor quality.
The drainage is poorly inserted, or it cannot cope with such a volume of water, or it is completely clogged.
In addition to the leakage of a plastic window during rain, there is another cause for concern - rubbing and fogging of the glass from the inside, the appearance of condensation.

Reasons for the appearance of moisture inside PVC windows:

Poor quality glass. Often, unscrupulous manufacturers make it from cheap and low-quality materials; subsequently, the double-glazed window does not fully perform its heat-protective function, the glass freezes and condensation appears.
Insufficient ventilation. You just need to skillfully use the microventilation mode, ventilate the rooms regularly, 10–15 minutes of ventilation per day will be enough.
Increased humidity in the house. Especially in the kitchen, while cooking or boiling water.
Incorrect installation, the window is blown out in places and moisture loss is inevitable in winter.
If a window leaks during renovation, this is normal, because building materials contain moisture and gradually release dampness to the air.

High humidity

This is the main answer to the question why condensation forms on windows, especially plastic ones.

The room atmosphere is oversaturated with moisture if:

the roof is leaking;
basement is too damp;
ventilation does not work;
the heating system cannot cope with heating;
the window sill is filled with flowers;
There are too many people in the room.

When you breathe, moisture leaves the lungs along with carbon dioxide. The more people in the room, the more active they are (for example, during physical activity), the faster water evaporates from the body. That is why, when condensation collects on plastic windows, they say that it is because those present have “inhaled.”

The dampness increases during cooking. Boiling pots greatly saturate the air with water vapor. Fogging of glass is also observed during water procedures, washing, and wet cleaning. In this case, the problem is solved by ventilation.

Indoor flowers also actively breathe. Water evaporates from the leaves or directly from the pot immediately after watering. If the glass fogs up next to a flower, it is better to move it to another place. You can do the same with another source of dampness - an aquarium.

It's more difficult to get rid of fogging if the problem is a leaky roof or a flooded basement. Here I advise you to contact the company that manages the house. The same can be done if humidity accumulates due to non-functional ventilation. To check it, you need to bring a lighter or candle to the ventilation holes: if the flame deviates towards the ventilation duct, it means it is working properly, but if the fire remains motionless, the ducts need to be cleaned. Sometimes they are unknowingly bricked up by other residents during renovations.

Ways to eliminate condensation

Before describing methods of dealing with condensation, a little should be said about the double-glazed windows themselves.
The purchase and installation of two- and three-chamber double-glazed windows, especially in regions with cold climates, will help to a large extent to avoid the appearance of condensed moisture on the windows.

A single-chamber double-glazed window simply will not cope with this task.

Tips and methods:

Adequate ventilation should be provided. In the absence of a normal room ventilation system, you can do the following: open the windows twice a day for 15–20 minutes. Simple ventilation removes used air along with water vapor and brings in fresh air. Forced ventilation has proven its effectiveness.
This is a duct system that has fans built into it. If it is available, there is no need for normal ventilation. Even modern ventilation, using humidity and temperature sensors, can regulate the microclimate in various rooms according to your wishes: heat, dry, humidify, etc.
The next important factor is the finishing of window slopes, window sills and external ebbs while simultaneously insulating them. All together, this makes it possible to reduce heat loss and, accordingly, move the dew point back.
You should also pay attention to the balcony. It is better to order glazing of the balcony (possibly with single-chamber double-glazed windows) with simultaneous insulation of the floor, walls and ceiling of the balcony. In this case, condensation will certainly not form on the glass inside the room.
The location of batteries and heating devices is also important. It is advisable that convectors, radiators, radiators are located under the windows and the window sills should not completely block them from above. This will create a constant thermal curtain in front of the windows. Curtains and curtains are also an obstacle to heat loss. You should also be careful with open water surfaces, such as aquariums.
Don't forget about such little-used items as shutters, blinds and roller shutters. Since an air gap is formed between them and the windows, we get an additional barrier to heat loss. Roller shutters doors, among other things, can perform an aesthetic function, because they are produced according to individual orders and can be painted in different colors, bear photo printing, etc.

Taken together, these methods will help get rid of the unpleasant problem of condensation and even avoid unnecessary spending on heating.

Source: steklandia.ru/poleznoe/problema-kondensata-na-steklopaketah/

Convection mode

If the ventilation is working properly, the basement is dry, and the roof is not leaking, if the hygrometer shows a normal level of humidity in the room, but condensation still appears on the plastic windows, then the problem may lie in a violation of the convection regime. Convection is the natural movement of air. Warm air flows from the radiators rise upward, cold air flows down. This is how constant circulation of heat occurs.

Normally, convection currents heat window glass - that is why batteries are placed under windows. This heating prevents fogging. If the windows become foggy or leak, I advise you to check whether the window sill is too wide. It often blocks the flow of heat, causing the glazing to remain cold, which attracts steam. This problem is indicated by condensation at the bottom of the plastic window, just in a non-heated place.

There are several ways out:

The window sill can be shortened.
If the width cannot be changed, you can make ventilation holes in it or insert ventilation ducts.
Remove decorative radiator grilles or install structures that better transmit heat.

Convection is also disrupted by long, thick curtains. To get rid of the problem, you can shorten them, hang lighter tulle, or replace them with curtains. Or, if such a decision spoils the design ideas, you can move the cornice so that there is a gap of several centimeters between the fabric and the window sill.

Why is this happening?

Most often, condensation appears in the cold season , when the difference in temperature indoors and outdoors becomes noticeable.
The second factor is high humidity in the room. First, drops appear in the form of dew, then they roll down onto the profile and window sill.

There are several reasons for condensation that can be eliminated without replacing the structure:

Increased humidity in the room. The main factors that can lead to an increase in humidity are renovation work in the room, the condition of ventilation ducts and sanitary communications, roof leaks (top floor), steam in the basement (ground floor).
After repair work, no special actions are required. It is enough to ensure ventilation and cleanliness in the room. If the plumbing is faulty, repair it yourself or call a professional.
If the ventilation does not work properly, check the air flow using a thin sheet of paper. It needs to be leaned against the grille - if it is attracted, then the ventilation is working. You can repair the grill yourself; the channels should be cleaned by specialized services.
Read also: Simple instructions on how to wash windows with a window washer inside and outside without streaks
Convection failure. This happens when installing window sills that are too wide, covering the window with thick curtains, or an excess of moisture-loving plants near the double-glazed window. In these cases, proper air circulation from the heating device to the window is disrupted.
Such reasons can also be removed without reinstalling the window. It is necessary to ensure proper air circulation from the window sill to the window. To do this, you can cut in ventilation grilles or replace the window sill with a smaller one.
You should hang curtains made of loose fabric and move them away from the glass. Reduce the number of flowers by placing them at some distance from the frame.
Use of low-quality seals or fittings . Replacing parts will help here.

Solving such problems does not require any manipulation of the window structure.

You can find out more about why plastic windows sweat in another publication on our website.

When are radical methods needed?

There are also reasons that require radical action to be resolved. The main factor is defined in the legislative document - GOST 24866–99.

If condensation has formed on the inside of the window, then this is considered a design defect. In this case, adjustment will not help; reinstallation is indispensable.

If the window contains manufacturing defects or incorrect components, a complete replacement of the entire mechanism is necessary. For example, the composition of a double-glazed window that does not correspond to cold climatic conditions. If it consists of two glasses and one chamber, it will freeze quickly. Only a complete replacement of the double-glazed window will help remove this defect.

Depressurization of a double-glazed window occurs due to cracks or disassembly . Especially if you take it apart yourself. Lack of experience and knowledge may result in damage to the product.

Another reason for the appearance of condensation is installation errors. As a result, the glass unit becomes depressurized, as well as the distance between the frame and the wall. To correct the situation, you will need to remove ebbs and slopes and reseal all joints.

The microclimate is disturbed

Another common cause of the problem. Sanitary standards require maintaining a temperature inside residential premises from +18 to +22-23 degrees Celsius. Normal humidity is 30-45%. With these parameters, condensation will not appear on plastic windows. In non-residential rooms the temperature may be higher, but it should not be lower.

The room microclimate is disturbed not only due to sources of excess moisture, which I mentioned above, but also due to insufficient heating. In old houses, cast iron radiators are often clogged, which is why they heat poorly. It is enough to clean them to make the room warmer and the dampness to go away. They are often replaced with new ones made of steel or aluminum, but their service life is shorter than that of cast iron, so I advise you, if possible, not to replace them, but to clean the existing batteries.

If central heating cannot cope, you can install a heated floor system. Another solution is heaters. Installing convectors or fan heaters will also solve the problem of impaired convection. Infrared devices help eliminate mold and dry walls.

Detailed analysis of the causes of condensation

Indoor microclimate disturbances

So, what requirements are put forward according to SanPin for the microclimate in a residential area?

Please note that the most comfortable temperature for living is from +18 to +23 degrees, and the humidity should be from 40 to 50% and the air exchange rate from 3 m3 per linear meter in the room, if it will be used for relaxation and spending time during leisure time.

But keep in mind that in the kitchen the air exchange should be 2-3 times faster (with an electric and gas stove, respectively). From the recommendations we can conclude that a living space can be considered comfortable not only when it is warm, but also if enough fresh air gets into it.

Ventilation device

The apartment ventilation system of household type is installed in the sanitary unit and kitchen. Fresh air can enter the remaining rooms only during ventilation and through microscopic cracks. When winter comes, in houses where ordinary wooden frames are installed, natural micro-ventilation is blocked, since the window panels are covered with paper strips. But even with such protection, windows rarely begin to fog up. After the installation of plastic windows is completed, the situation changes dramatically if the design was chosen in such a way that no one took into account the peculiarities of the regional climate or certain mistakes were made during installation work.

So what is the essence of the phenomenon of condensation on plastic windows? There is a certain amount of moisture in the air space, and if it begins to come into contact with the surface, and the temperature of the latter is less than the “dew point,” then condensation begins to form. If glass on a window acts as such a surface, it fogs up. The degree at which condensation forms will not have a constant value. The dew point is for the most part tied to the relationship between room temperature and moisture-saturated air.

For example, if the room temperature is constant at +15 degrees, then condensation will begin to form at temperatures of +13, +7.3 and +1.5 degrees, if the air humidity is 90%, 60% and 40%, respectively. For this reason, it becomes clear that in damp and poorly heated rooms, windows constantly fog up. But where does the water on the glass in the house come from? Let's look at this issue further. Condensation can occur in a variety of conditions and will depend on the factors mentioned above as well as your own life processes. While a person is not in the house, the humidity level will be the same, but as all household members gather in one house, and also depending on the type of activity, the amount of water in the room will increase.

For every hour, approximately this amount of water is formed in each house:

From breathing - 40-90 grams from each person.
If there are growing plants in the house - up to 10 grams from a small bush.
For cleaning and cooking – 1 kg.
Taking a bath and shower – up to 2.6 kg.
When washing in a machine – up to 300 grams.
If you have a medium-sized aquarium - up to 200 grams.

But how much more water is there in the building mixtures that were used during the finishing of housing and washing wallpaper? Moisture can remain inside such objects for up to 2 years. If the air inside the apartment rarely warms up by more than +17 degrees, then there are all the prerequisites for condensation to appear.

How to avoid this phenomenon?

There are a number of specific and proven methods that need to be used at least 1-2 times a day:

Keep the windows slightly open for a long time so that the air in the apartment dries out (an excellent option only for those apartments with good heating).
Open all the windows in the apartment wide open for 15 minutes (unlike moisture, you will not lose much heat).
Arrange 2-minute ventilation with opening the front door and windows (make sure that with such a sharp change in the humidity level, all open elements of the frame structure and the door are well secured and do not slam).

At the same time, do not forget to check that warm air from the radiator flows not only into the room, but also to the curtains, and that the same ones, in turn, are slightly separated from the edge of the window sill.

Mistakes when choosing plastic windows

If you are tormented by condensation that constantly remains on the glass, and the windows are plastic, then it is possible to eliminate the problem if you replace standard plastic structures with energy-saving ones. This will only help if the installation work is carried out by a specialist, and not just someone you know from the street.

Problem due to technology violations during the assembly of a double-glazed window

If you attach defective sealing rubber to the glass of plastic windows where condensation forms, or if you incorrectly install certain elements of window fittings, then even the most expensive double-glazed windows will not be able to meet the owner’s expectations. In certain similar cases, the problem can be solved if the fittings are installed correctly.

Problems due to improper installation and design of slopes

If you are 100% confident in the window manufacturer, then there are assumptions that the cause of the “fog” may lie in poor-quality foaming of the frame or poor vapor barrier coating. Sometimes builders can completely “forget” about the last factor, since they simply do not know how to properly install waterproofing into a window structure. For this reason, only professionals should be allowed to install windows. Believe me, correcting mistakes that were made during the installation of plastic windows is much more difficult.

Other reasons

Condensation on glass can form in both a structure with a plastic panel and a wooden one. The main reasons for “fogging” are:

Seasonal cold.
A lot of moisture in the room.
The window structure has poor thermal insulation.

Since you definitely won’t be able to cope with the cold outside, all that remains is to either influence the level of humidity inside the room, or replace the double-glazed windows with more modern ones, moreover, they must have enhanced thermal insulation (with a special coating and a double chamber). Don’t think that only modern windows can “sweat”. Condensation can appear anywhere, and the type of material that was used to create the profiles will not be the main reason. It all depends on the tightness of the selected window design.

Even the same windows from a Finnish manufacturer with a load-bearing wooden frame and double-glazed windows will sweat less than windows made according to European standards and having a single chamber. This is due to different thermal insulation properties - in two-chamber windows, thermal energy insulation is much better. There is water vapor in the air, and as the temperature rises, the amount of moisture in the air begins to increase. If you bring something really cold into a room that is saturated with moisture, an invisible “casing” of cold air will immediately begin to appear around you. Such a temporary shell is not capable of retaining a lot of moisture, as does the rest of the air in the room, so the surface of the introduced object will very quickly become wet due to that very “dew”.

The more water there is in the atmosphere, the less “demanding” the moisture will be regarding the temperature level of objects on the surface of which it will fall as condensation. It turns out that they no longer need to have the same temperature as vegetables from the refrigerator or a bottle of drink. If the saturation in the air is approximately 100%, then steam will begin to settle on all objects whose temperature differs by 1 degree or even less from the temperature of the atmosphere.

When the inner glass in the double-glazed chamber has the same temperature at which the formation of the dew point begins or even lower, the humidity inside the structure will also correspond to a certain parameter, and there will be even more condensation on the plastic window. For this reason, “tears” on the glass are direct evidence that there is a high level of humidity inside the house.

There are the following possible reasons:

The result of daily activities throughout the apartment.
Disturbed ventilation process.
A glass unit with damage or defects.
Violation of the technology for installing a glass structure in the frame opening.

If the essence of the problem is that the air is poorly conditioned, then the appearance of condensation can be perceived as a call to ventilate the room once again. But if, even after ventilation, the glass begins to become cloudy again, and frequent opening of windows will result in excessive heat consumption, then it makes sense to start stabilizing the ventilation system, and even find a replacement for the already installed double-glazed window.

Important! Try to select a new design that takes into account typical temperature fluctuations for your region.

If in your area the temperature in winter -20 degrees is quite normal, then the double-glazed window should be taken taking into account the parameters of the appearance of the dew point and the level of humidity and heat of the air inside the room that is comfortable for you and your family. If your normal air humidity is 60%, and the air temperature is about +20 degrees, then in such conditions the dew point will be +12 degrees. At the same temperature and humidity of 40%, the dew point will be +6 degrees. How to use this knowledge in practice?

When studying the range of double-glazed windows, you should pay attention to the indicator, the measurement unit of which is C/W. With the initial data described above (outside -20 degrees, inside the house +20 degrees and humidity 40%), the thermal insulation value of the window structure, i.e. Rо should be greater than 0.35 m2оС/W. When the humidity increases, for example, to 55%, the new value will be 0.54 m2oC/W. What else do you need to know when selecting a new double-glazed window?

Please note that if the supporting structure with a distance-type frame is made of aluminum, then cold bridges will appear at the edges of the metal products.

Because of this, when cold weather begins, there is a possibility of condensation appearing on the glass near the line of contact between the transparent elements and aluminum profiles.

We suggest considering additional measures to reduce the likelihood of condensation on the glass of PVC windows:

Find out whether near all (or not) windows the heated air from the radiator reaches the glass (a strongly protruding edge from the window sill and closely spaced curtains can interfere with the process).
Install a ventilation valve that allows a portion of fresh air to flow to the surface of the glass, which will also help in the fight against condensation.

Now let's look at how to deal with this.

Incorrectly selected glass unit and errors in its assembly

Plastic windows need to be selected based on the climatic characteristics of your region. The wrong choice of double-glazed windows and profiles is one of the main reasons why condensation forms in the apartment.

Where winters are warm, a single-chamber double-glazed window is sufficient. It is suitable for southern regions or for cold glazing of balconies and loggias. In the middle zone, or even more so in the north, only double-glazed windows consisting of three glasses should be installed. Additionally, glass can be coated with special coatings that reduce thermal conductivity properties.

If in a cold climate you install a thin profile and a single-chamber double-glazed window, it will cool down too easily due to frost. The dew point will move inside the room - and fogging is inevitable. During severe cold weather, frost and ice form. In this case, there can be no talk of preserving heat. Savings are inappropriate here; it only results in even greater expenses for replacing window components.

If a suitable profile and a reliable double-glazed window are installed, but the glass still flows, an error may have been made during assembly. If drops appear inside the glass unit, this is a 100% defect. This means the seal has been broken.

A little about window ventilation

The same comb on the window

As mentioned above, most often the most effective way to combat the formation of frost on glass is high-quality ventilation. The window structure must be equipped with ventilation.

Windows with a window. Today, windows with a window are extremely rare; they are made only according to the individual orders of the buyers themselves. But this design is most effective in combating condensation. The flow of cold air from the street is easily regulated; it penetrates into the room at the top of the room, where it combines with warm room air. This improves the microclimate in the room.
Micro-ventilation. It has already been mentioned before, now let’s look at this method of ventilation in more detail. This is the name of the ventilation mode, which is found in almost all modern window designs. The window opens just a little, leaving a small gap through which air exchanges. Through this gap, a lot of cold air will not be able to penetrate into the room, so ventilation in this mode will not bring discomfort to the inhabitants of the house, even in cold weather.
Self-ventilation. This function is initially present in all window designs. It consists of many small holes in the lower and upper frames of the window. Air circulation eliminates fogging, cold air enters in the lower part, and air leaves the room through holes in the upper frame.
Combs on the windows. A comb is an accessory for plastic windows that can be purchased at any specialized store. It helps regulate the intensity of ventilation and opening of the sash.
Ventilation duct. Many people neglect to install it right away, and install it only after a problem appears. Such a ventilation duct is installed either under the window sills or in the profile itself. The devices are completely different. The cost of such a channel is quite high, so ventilation installation should be done by a professional.

Illiterate installation of windows and slopes

Installation errors are difficult to notice in summer. They usually appear in winter, when the outside temperature drops. The cause of condensation on plastic windows is insufficient insulation during installation. Excessively thrifty installers often save polyurethane foam and do not fill the seams with it as expected. As a result, voids remain that are unable to retain heat. The glass cools down and fogs up.

The technology requires the use of three-layer insulation. Foam alone is not enough; profiles must be secured using special insulating tapes. Then the foam must be additionally protected from the sun, under whose rays it quickly collapses. To ensure that everything is done correctly, I advise you to contact trusted companies that value their reputation and do not make mistakes.

Condensation can settle not only on windows, but also on walls. Sometimes this happens when the apartment owners, for reasons of economy, decided to install the slopes themselves, but in the process violated the technology. For example, they neglected insulation, insulation, or chose low-quality plaster, paint, or other finishing material. As a result, in winter not only the profile, but also the entire window opening cools down, and the decrease in temperature leads to moisture settling on the wall.

Why is condensation dangerous?

If plastic structures begin to fog up, it may seem unpleasant, but it is harmless. In reality, everything is not quite like that. Excess moisture spreads from the glass to the window sill, walls, and ceiling. In such conditions, fungi and microorganisms thrive very well, including many that are dangerous to humans. In a warm, humid environment, they quickly multiply and “spread” around the room.

Allergy sufferers and people with respiratory diseases will feel especially bad in such conditions. But that is not all. Damp construction and finishing materials swell and begin to collapse. Sometimes this process goes very quickly; after just a few months, a good repair becomes unusable.

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Defective or incorrectly selected window

Often, when people see condensation on their windows in winter, they blame the company that installed the profiles. However, dissatisfied customers are right in their accusations only 3-5% of the time. Marriage is rare. However, to understand why cloudiness occurs, it is really wise to call installers. They will inspect the window structure, if necessary, use a thermal imager and find the source of the problem. Defects can be indicated by the fact that, with the same humidity in the entire apartment, only one window fogs up.

Both double-glazed windows and profiles have air chambers. Plastic frames are also selected according to climatic conditions. It is better not to save on too thin profiles with three chambers, because they do not retain heat well, easily fail, and are sometimes made of low-quality plastic, especially if you contact dubious companies. According to the standards, the optimal thickness of the outer wall of the profile is 3 mm; for central Russia, the number of chambers should be at least three, and the frame depth should be from 60 mm.

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Features of plastic construction

To understand the reasons why condensation may appear on the glass, it is worth deciding on the design of the system. Its distinctive feature is its modular structure, which means the presence of several block modules. Their number and location are always constant, but the models can be very different. Each structure includes:

Frame. This is a frame made of a hollow profile with metal reinforcement. Provides durability. Sashes are inserted into it if an opening system is intended, or continuous glazing.
Filling the opening. Most often this is a double-glazed window, but it can be single glass or several separate glass sheets. Sometimes there is an opaque sandwich panel.
Accessories. A set of mechanisms that are responsible for the process of opening and closing in various modes.
Installation elements. These include special profiles, window sills, drainage, flashings and slopes, if they are made of plastic parts.

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Thanks to its design, the plastic window is completely sealed. If installed correctly, it retains heat well inside the room and does not allow street noise into the room.

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How to insulate plastic windows with your own hands: detailed instructions

Other reasons

Sometimes the sources of moisture are quite unexpected. For example, condensation often appears on windows in a new building or after a major renovation of any building. The fact is that some building materials retain moisture for up to two years. One of them is concrete, cement-sand screed. Other materials - glue, plaster, various mixtures - dry faster, but they can also evaporate excess liquid for weeks.

The opposite situation is that the house is too old. It is exposed to weathering, the exterior finish is gradually destroyed, cracks appear, and drafts arise. The temperature in the room drops, the air gets rid of water vapor, which settles on the glass.

When there has been no repairs for a long time, but the house is like new, the ventilation is working, the heating is working properly, dampness is excluded, the windows can still fog up if there is a very strong frost outside. In this case, there is no need to worry; as soon as it gets warmer, the problem will go away.

What to do if the windows in your house sweat

So, we found out that windows in a private house sweat for two reasons: humidity and low glass temperature. Accordingly, the struggle for microclimate comes down to increasing temperature and decreasing humidity.

You can increase the glass temperature in the following ways:

We replace old windows with plastic 2-chamber windows with energy-saving glass. If plastic windows are already installed, then you can simply replace the double-glazed windows with more energy-efficient ones. (radical but effective way)
We dismantle the windows and install them with a shift towards the room. (also radical way)
Window sills should not interfere with proper air convection. Make sure that the window sill does not cover the battery by more than 2/3.
Make sure that thick curtains do not block the radiators.
Raise the temperature in your home.

We fight moisture in the following ways:

We check the operation of the hood, if there is one. If there is no hood, then it is better to make one. While there is no hood or it is not working efficiently, you can open the damper in the fireplace - the fireplace draft can partially serve as a hood.
Ensure an influx of fresh air by installing supply valves on all window sashes, or turn on micro-ventilation mode in the windows (if available), simply open the window slightly to ventilation mode.
Get rid of sources of moisture (get rid of leaks, flowers in pots, aquarium, etc.)
Make sure that the interior doors are not airtight and have at least 2-3 cm gaps between the leaf and the floor.
Ventilate your home regularly.

We figured out why plastic windows sweat in a private house and how to deal with this phenomenon.

Source: okna-lider.com/pochemu-poteyut-okna-v-chastnom-dome/

The consequences of window fogging and what will happen if you don’t deal with it

The appearance of condensation is not only an aesthetic problem. Many people easily accept the fact that plastic windows, when fogged up, temporarily lose their vaunted transparency. However, neglecting this nuisance can lead to much more serious problems.

Firstly,

the degree of illumination decreases. In winter, the days are already very short, it is better not to deprive yourself of sunlight. It is useful for the eyes, immunity, and finally, for the prevention of clinical depression.

Secondly,

Condensation on windows leads to constant dampness, and this is an ideal environment for the proliferation of pathogens, bacteria, fungi and mold growth. The air becomes musty and unpleasant, like in a damp basement. A runny nose appears, the mood of household members deteriorates, sleep is disturbed, and the risk of getting sick increases.

Thirdly, mold, dampness, and bacteria spoil finishing materials. There is nothing pleasant about green and black stains on slopes, ceilings and wallpaper, and they are very difficult to remove. Constant freezing destroys the insulation, and it begins to blow from the frames. In particularly advanced cases, structures become fragile, which threatens dangerous destruction.

All about methods to combat window fogging

Features of window systems

Causes of fogging

What are the dangers of sweating double glazed windows?

Seven ways to solve the problem

Traditional methods

Systems made of plastic and glass have long replaced the once most common wooden ones. This can easily be explained by the better performance and convenience of more modern models. However, they also have disadvantages. Sometimes plastic windows sweat, and we’ll figure out how to fix this problem.

How to get rid of condensation

Before you start getting rid of condensation, you need to find the exact reason why drops appear on plastic windows. If you were unable to discover the source of the problem on your own, I advise you to call installers from the company that installed the profiles, especially if the warranty is still valid. However, if the company seems unreliable, you can turn to more professional specialists.

There are also universal remedies that you can try before contacting the specialists:

elimination of heat loss;
drainage;
installation of ventilation;
application of chemistry.

The main causes of condensation

Poor ventilation. The coldest surface in a heated room is window glass. Therefore, the steam contained in the air always settles on the windows.

Excess moisture is formed during bathing procedures, cleaning, and cooking.

To maintain an optimal microclimate, the premises are equipped with a ventilation system that promotes the flow of dry air. A faulty ventilation system is the main cause of dew point formation.

In wooden windows, unlike plastic ones, fogging is less common. This is due to the less tightness of wooden window frames - natural ventilation.

Wide window sill. Water can accumulate under the window if the window sill is installed too wide and thick curtains are used. Such obstacles prevent warm air from rising and the glass from warming up. The window becomes supercooled and water droplets appear on the surface.
Depressurization. In places where the window is depressurized, condensation appears inside and ice appears. Reasons for depressurization: old wooden window frames, defects, unprofessional installation of double-glazed windows.
Poor quality slopes. Improperly made slopes also cause condensation on the windows in the house. The problem arises if construction foam was not used during the installation process (or the spaces between the frame and the opening were poorly foamed) or insulation materials (mineral wool).
Incorrectly selected glass for the double-glazed window. Independent choice of double-glazed windows leads to the appearance of condensation from the side of the room. That’s why here at Window Factory, its selection is carried out by experienced specialists who take into account all the features of the room.
Defect. In rare cases, in double-glazed windows there are defects in one of the glasses. Unscrupulous assembly and installation also lead to the formation of defects that contribute to the appearance of condensation.

Construction work. In houses where renovations have recently been made or construction work has been completed, condensation is observed.

In such rooms, windows may fog up for several years. After 1 or 2 years the problem will resolve itself. You can speed up the process by using a heat gun, which will quickly and safely dry the rooms.

The residents' fault. The humidity in the room is also affected by the behavior of the residents: constant cooking without the use of hoods, ventilation, airing; frequent hand washing; faulty plumbing; drying a large amount of laundry; a large number of flowers on the window sills.

Elimination of heat loss

If condensation appears on windows as a result of problems with thermal insulation, you can:

replace sealing contours;
switch windows to winter mode;
make sure that the cracks around the frame are securely sealed;
install slopes made of plastic panels with insulation or sandwich panels;
insulate the walls.

Sealing rubber bands wear out over time and lose their elasticity and tightness. Sometimes they become deformed due to improper use of the window or as a result of accidental damage. All that remains is to replace them with new ones. They are carefully removed, then new rubber bands are inserted into the grooves without stretching.

Profiles released in the last ten to fifteen years support settings for summer, winter and demi-season modes. In winter mode, the sash is adjacent to the frame with the greatest density, in summer mode it is most loose. The tighter the fit, the higher the tightness. In winter, this prevents drafts with freezing, but in summer the cold is not terrible, so the clamp is loosened for ventilation. To switch, you need to turn the eccentrics of the trunnions at the end of the sash.

You need to check the sealing with polyurethane foam under the window sill, as well as along the entire perimeter of the frame, inside and out. If necessary, the voids must be filled, and then the foam must be covered with finishing materials so that it does not collapse from street dampness and ultraviolet radiation. This is done including slopes. I advise you to equip them with plastic panels or sandwich panels. This guarantees tightness, insulation and durability.

The most radical method is complete insulation of the walls. It is better to attach the insulation material to the outside of the building, so this method is not suitable for every high-rise building; it is usually used for private houses. Additionally, you can insulate the roof and floor if necessary.

Useful tips

Sometimes you can solve a problem with condensation relatively quickly, without going through possible options for the appearance of moisture, if you look closely at the foggy window.

Condensation is only along the contour - the glass does not fit tightly to the frame, there are cracks and gaps. It is necessary to change the seal or supplement it.
Moisture is only in one corner or along one side. It looks like the sash in this place does not fit tightly to the frame or there are gaps in the wall/slope. We check for drafts and eliminate cracks.
Spots of condensation near the handles or hinges of the sashes indicate a loose connection of the fittings; everything needs to be checked and adjusted.
The glass fogs up only near indoor flowers standing on the windowsill. We move the plants to another place - they are warmer, and the glass does not “cry”.
Moisture is everywhere, not only on the windows - we urgently arrange forced ventilation and warm the room!

The last measure is suitable for all cases of condensation on PVC windows and in rooms in general.

Air dehumidification

This is the second method of combating fogging. Suitable for drying:

heaters;
special dehumidifiers;
improvised means.

If the humidity is not too high, but sufficient to make the glass “cry,” you can spread salt on the windowsill. Any kind will do - sea, food, coarse or finely ground. After some time, it can be calcined in the oven and reused. Wood or activated carbon and silica gel also absorb moisture. If condensation appears at the bottom of a plastic window due to lack of convection, it can be eliminated with ordinary candles. One or two candles can dry the glass, creating heat flows. The main thing is to monitor safety so that there are no flammable objects nearby. I advise you to light thick candles that burn for at least ten hours.

The easiest way to dry out is regular ventilation. Usually it is enough to open the doors three to four times a day for five to ten minutes.

Fighting condensation on plastic windows

Condensation is the most common problem that manufacturers of PVC windows and their consumers have to face.

It should be noted that condensation is not only an unpleasant aesthetic defect, but can also cause dampening of building structures and, as a result, the appearance of mold!

According to standards, the temperature of indoor air in premises should not be lower than +18°C; in a number of regions, Territorial Construction Standards (TSN) have been adopted, which prescribe the temperature of residential premises not lower than +20°C.

If the temperature is below standard, then you need to check the heating system, because this may cause condensation.

Condensation forms primarily at the bottom of the glass unit. Due to convection, cold air accumulates in the lower part between the glasses.

Therefore, the bottom and lower corners of a glass unit are the coldest parts of a modern window structure.

Since the question of the regional zone arises often, the Gosstroy of the Russian Federation gave an explanation on this problem in letter No. 9-28/200 dated March 21, 2002:

1. Condensation in the edge zones on the inner surface of double-glazed windows during the winter period of operation is usually associated with the presence of an aluminum spacer frame in their design and the convection conditions of the gas-air filling.

International standards (ISO, EN standards) allow temporary formation of condensation on the inner glass of a double-glazed window.

But the standards for window units do not normalize the formation of condensation, since this phenomenon depends on a complex of third-party factors: air humidity in the room, design features of the junction points of window units, insufficient air convection along the inner glass (due to a wide window sill, improper installation of heating devices ) and etc.

At the same time, GOST 24866-99 does not allow condensation to form inside the glass unit, which should be considered a significant defect leading to a decrease in standardized performance characteristics.

As for high air humidity, this phenomenon is characterized by the following main reasons:

Insufficient air exchange due to too tight windows and, as a result, poor performance of exhaust ventilation.
Increased humidity in building structures due to recently completed construction or renovation work. Building structures retain moisture for one to two years after completion of work!
Peculiarities of everyday behavior of residents. For example, a greenhouse on the windowsill or drying baby diapers in the kitchen...

New standards SNiP 23-02-03 “THERMAL PROTECTION OF BUILDINGS” have determined the design parameters of the relative humidity of premises to determine the dew point and temperature requirements on the inner surface of windows:

5.9 The relative humidity of internal air to determine the dew point temperature in places of heat-conducting inclusions of enclosing structures, in corners and window slopes, as well as skylights, should be taken:

for premises of residential buildings, hospitals, dispensaries, outpatient clinics, maternity hospitals, boarding homes for the elderly and disabled, comprehensive children's schools, kindergartens, nurseries, kindergartens (plants) and orphanages - 55%, for premises kitchens - 60%, for bathrooms - 65%, for warm basements and underground areas with communications - 75%;
for warm attics of residential buildings - 55%;
for premises of public buildings (except for the above) - 50%.

5.10 The temperature of the inner surface of the structural elements of the glazing of windows of buildings (except for industrial ones) must be not lower than plus 3°C, and of opaque window elements - not lower than the dew point temperature at the design temperature of the outside air in the cold season, for industrial buildings - not lower than zero ° C.

What other errors can lead to condensation? It is necessary to check the room for the presence of a cold surface!

The reasons for the appearance of cold surfaces may be related to resistance to heat transfer and ventilation of structures. They may be as follows:

Errors in window manufacturing:

A “cold” double-glazed window with low heat transfer resistance was installed, which does not meet the standards.
Violation of clearance tolerances, use of non-standard seals or incorrect installation of hinges are the reasons leading to window blowouts.
Non-opening sashes have drainage holes measuring 5x20 mm instead of holes for draining the cavity between the edges of double-glazed windows and the folds of profiles measuring 5x10 or with a diameter of no more than 8 mm.

That is, we are talking about a violation of the provisions of GOST 30674-99, clause 5.9.5 and clause 5.9.6 regarding the system of ventilation and drainage holes. We sent out a letter on this topic, and we want to remind you again: according to GOST, there are drainage holes and there are ventilation holes. These are different types of holes!

In the letter of the Gosstroy of Russia No. 475 dated September 10, 2002, paragraph 2 states that “if the sashes do not open, the dimensions and location of the holes in the lower profile of the frame should not contribute to overcooling of the lower edge of the double-glazed window.”

Confusion in this issue is often associated with terminology: in GOSTs there is no concept of “fixed” glazing or window, but there is the concept of “non-opening sash”!

That is, in the version that in everyday speech we call “a fixed window or glazing” in the terminology of the standards - “non-opening sash”!

Ventilation installation

If full ventilation is impossible due to severe frosts, you can choose profiles with a micro-ventilation mode. It involves the installation of special fittings. By turning the handle diagonally (about 75 degrees), you can move the sash to the side so that a gap only a few millimeters thick appears. This is enough to let in fresh air, remove excess dampness, but not lose heat.

Another solution is to install ventilation valves. They are either mechanical or automatic. Mechanical valves allow you to independently select the ventilation intensity by adjusting the mechanism. Automatic devices are equipped with climate sensors. They respond to changes in humidity and temperature, opening the ventilation passages wider or narrower, maintaining an optimal microclimate.

The solution for the kitchen and bathroom is a hood. By turning it on when cooking or during water procedures, you can avoid not only fogging, but also the spread of odors throughout the apartment.

The easiest way to remove condensation is to install a fan. It is suitable as a temporary solution for plastic window sills, slopes and profiles, if only one or two windows become damp, which then will have to be dealt with more precisely in order to completely remove the problem.

Dew point concept

Dew point is the temperature at which water changes from a gaseous state to a liquid. This point is located in the thermally insulating layer of the wall, and is located at different levels in different situations. This point cannot be detected visually; it is only marked on the graph.

The dew point is directly proportional to the humidity level in the room

The most important rule is that condensation forms due to temperature and humidity. The lower the humidity in the room, the lower the dew point.

Factors that influence dew point:

outside temperature
wall thickness
room temperature
indoor humidity
humidity outside

Glass processing means

Special chemistry can serve as a temporary measure. For example, products for treating car glass. Before using them, all dirt must be removed from the windows.

Other compositions for combating condensation:

detergents containing alcohol;
glycerin soap or its solution;
a mixture of glycerin, potassium oil and turpentine in a ratio of 20:40:4;
saline or chalk solution.

Previously, glass was wiped dry with newspapers. Printing ink repels water, so this method can also be used now. However, any chemical reduces fogging for a short time. If the dampness does not go away, then the fogging of the glass will gradually return.

Installation errors

Errors when making an assembly seam: incomplete foaming, which reduces heat transfer resistance; poor protection from external climatic influences, which leads to foam blowing or getting wet; absence or poor vapor barrier, which also leads to the insulation getting wet, but with steam from the side of the room.
“Cold bridge”, when, due to improper design of the junction unit, the window ends up in a cold, sometimes even negative temperature zone of the wall. This reason often occurs when heavy condensation appears.
Blowing through a wall structure, for example, a brick one, through empty seams - “empty space”. This phenomenon can be encountered in houses of the socialist period - the builders did not fill the vertical seams well. But this has also become a problem in new construction with multi-layer walls, when the mineral wool is covered on the outside with brick or other cladding. In this case, the insulation must be ventilated, and when the windows are placed in the plane of the insulation, they may be exposed to cold air from the side of the junction. In this case, during installation, it is better to separate the wall from the junction unit with a layer of foamed polyethylene 6-10 mm thick.
A wide window sill prevents the convection of warm air from the radiator in the window opening.

Therefore, we can give the following tips to eliminate the possibility of condensation:

If, after all, condensation is a consequence of increased air humidity, then this cause must be eliminated due to the increased likelihood of mold appearing in the room.
To reduce indoor air humidity and move the dew point to lower temperatures, we recommend installing a Regel-Air climate valve or ventilating the room for 10 minutes twice a day.
Heat losses with such ventilation are insignificant even in winter and amount to no more than 3 degrees.
The intensity of ventilation of the room must be increased during repair work.
The window sill should not be very wide and prevent the passage of warm air.
To allow warm air to pass through to the window, place the curtains at some distance from the window sill.
Decorative screens on heating radiators should not interfere with the passage of heat flows from the radiators.
It is necessary to periodically check the exhaust ventilation system in your home or apartment.

One of the most effective ways to combat condensation will be to install a window with a five-chamber “Favorit” system, developed (Germany) specifically for Russia.
The temperature on the inner surface of the profiles directly depends on the heat transfer resistance of the profile system. For example, we can consider two cases - at an external temperature of -26? C and at -31? C (at an internal temperature of +20? C and a relative humidity of 55%).

The dew point will be +10.7?C. Temperatures on the surfaces of a standard binding (three chambers and a width of about 60 mm) and a five-chamber binding with a heat transfer resistance of 0.78 m2? C/W will be as follows:

Binding option	Temperature on the binding surface at an outside temperature of -26 C	Temperature on the binding surface at an outside temperature of -31 C
Binding with 0.63 m2 C/W	11.82 C	9.79 C
Binding with 0.78 m2 C/W	13.22 C	12.48 C

Source: ashdom.ru/articles/fenstr_1.htm

A guide for those experiencing condensation for the first time

If, some time after installing the windows, condensation forms for the first time, I suggest the following procedure:

Remove everything that blocks the window: blinds, roller blinds, curtains, etc. If possible, it is better to choose lighter, shorter curtains or at least hang them away from the glass.
Check the functionality of the batteries, especially if the apartment is noticeably cold in winter. Condensation on the inside of the window will most likely evaporate as soon as the room warms up well enough.
Turn on the hood. Open the sash for micro-ventilation. If this causes almost no air movement, check the ventilation ducts. They may become clogged, blocked by neighbors, or birds or pests may become stuck in them.
If there is no effect, install an air dryer.
Install a ventilation grille in the window sill or place an exhaust valve under it.
If you really want to cover the terrible batteries with a screen, it is better to choose a grille that minimally blocks the air flow.
To combat heavy condensation, you can combine methods. For example, put moisture-absorbing materials (salt, coal, silica gel) on the windowsill, and stick nichrome thread or a special conductive film on the windows. By connecting it to a 12-24 V power source, you can achieve the same effect as heating the windows in a car. The main thing is to make sure that the heating is not excessive, otherwise the glass will burst.

Methods of disposal

Today, experts offer several effective ways to get rid of fogging on windows.

Ventilation valve

It is purchased in a specialized store, has a fairly budget price, and provides instant relief from the problem. But only if it is not associated with low-quality window frames. The ventilation valve is mounted on top of the window profile. This arrangement allows for increased flow of fresh air without drafts.

Expert opinion

Kukushkin Anatoly Sergeevich

Repair specialist

Sometimes the cause of condensation lies in poor installation of the window system. In this case, you will need to check the entire frame for possible holes and foam them well. It happens that the only solution is to insulate the house from the outside or install energy-saving double-glazed windows.

Winter mode

In another way, this mode is also called micro-ventilation or micro-mode. Most window systems have it and help prevent water from appearing on the glass and window sill. With this system, the opening part of the window moves away from the frame by 1-3 mm. This small gap ensures the flow of fresh air, but at the same time retains heat in the apartment. With this mode, you don’t have to worry about freezing or catching a cold.

Ventilation

Excess water will not collect on the window frames if you constantly ventilate the room. It is especially important to do this in the cold season to equalize the temperature of the glass inside and outside. Many good quality window systems have special ventilation valves for automatic ventilation. Such systems virtually eliminate the appearance of traces of fogging even in the kitchen.

burning candle

This unusual method works great with cheap and expensive systems in the cold season. You need to put several candles on the windowsill and light them. The heat generated during combustion will prevent condensation from collecting. Usually, to eliminate fogging, thick candles with a diameter of 5-10 cm are used.

This method is more of an auxiliary nature and requires constant monitoring from the outside. Candles should not be left in the nursery or at night.

Convection screen

A more expensive solution, but it works great in warm and cold seasons. A convection screen is a small plate that can redirect air masses from the battery to the window frame. Such screens should be made slightly larger than the width of the heating equipment. They are usually installed at an angle of 30 to 60 degrees. You can purchase a convection system in specialized stores and immediately attach it to the battery.

Use of chemistry

A cheaper, but more effective way to combat fogging is regular automotive chemicals. It is enough to purchase an aerosol or liquid with an anti-fog effect and apply it to all windows. After spraying, be sure to wipe and dry the glass and window frame thoroughly. Automotive chemicals help reduce the amount of water several times, but cannot completely stop its formation. Anti-fog agents should be used 1-3 times a week, depending on the complexity of the problem.

Ventilation system

The fan will provide a constant flow of air. It should be placed on the windowsill. In order not to provoke the opposite effect, the fan must be turned on at minimum power. If there are several windows in a room, you need to install equipment on all of them at once. There are small book-sized fans available in stores that are ideal for this task.

Electrical system

A rather original method that requires careful handling. The entire window frame is covered with foil or foil film. After this, a small generator needs to supply this structure with a current of 12-24 V. The foil will warm up and generate heat, which will prevent fogging of the windows.

It is important not to overdo it with the current, otherwise there is a risk of the foil igniting, which will lead to a fire.

How to prevent condensation on windows

Fighting condensation on plastic windows can exhaust all your strength. Therefore, it is better not to wait for fogging to appear, but to foresee all possible causes of this problem. In essence, prevention repeats the methods for eliminating the problem, but to consolidate the methods, it is better to list them again.

Ventilation

The simplest method of getting rid of excess moisture. There will be no dampness at home if you open the doors three or four times every day for 4-5 minutes. For efficiency, you can open windows and entrance doors. The main thing is to make sure that the doors do not flapping under gusts of wind.

To avoid hypothermia, you can install frames with micro-ventilation mode. Turning the handle to a diagonal position opens the sash a couple of millimeters. Through such a gap enough fresh air penetrates to remove dampness, while there is no noticeable heat loss.

Installation of valves

In order not to keep the windows open, you can install supply valves on plastic profiles. They are mounted at the bottom or top of the frame. The device has a ventilation duct passing through the profile. From the outside it is closed with a grille. Inside there is a winding air passage, as well as a filter. The device provides a constant flow of air, preventing condensation from accumulating.

Depending on the model, you can adjust the ventilation intensity mechanically, by closing or opening the valve yourself, or automatically, relying on a climate sensor.

An alternative is to install more advanced climate control equipment, for example, a breather. The device keeps the window frame intact since it is mounted into the wall. The device acts as an improved air conditioner that takes air from outside, heats it, cleans it of dust and impurities, and then supplies it to the room. The musty damp air of the apartment is forced out through the ventilation.

To install the breather, select a place on the wall - for example, near a window, near a radiator, under the ceiling. The selected area is drilled with a diamond tool. The hole is insulated, covered from the outside with a grille, and additionally protected with sound insulation. The connected device fits tightly against the wall, preventing drafts. You can control it through an application on your smartphone.

Convection screens

Modern interiors do not welcome open radiators. However, they are needed to heat the glass so that it does not sweat. The solution is to install convection screens. They are placed on window sills. Such screens are equipped with plates located at an angle of 30-60 degrees to direct the air flow directly onto the glass. This allows you to avoid not only ice, even in severe frosts, but also fogging.

Insulation and finishing

To prevent the glass from getting wet, you need not only to choose the right profiles and double-glazed windows, but also to thoughtfully approach the slopes. Dampness cannot be avoided if you use plaster or neglect insulation. The optimal way to finish slopes is plasterboard with insulation and waterproofing. But it is better to finish them with plastic or sandwich panels. They will eliminate freezing and drafts. With them, the walls will be warmer, which means there is less risk of condensation or ice.

To retain heat, increase the dew point, and move it outward, the external walls of the house can be insulated. Mineral or stone wool, polystyrene foam, and any other materials are suitable. For efficiency, they are supplemented with vapor barrier and wind protection. A ventilation gap is maintained between the facade finishing and the insulation so that all moisture escaping through the walls evaporates without hindrance. As a result, the walls will be warm, heat losses will be reduced, and therefore the likelihood of dew forming on the glass will be reduced.

When “window operators” are to blame for condensation

The cause of fogging may be hidden in an incorrectly manufactured or installed window:

The thickness of the profile and the glass unit installed in the opening are insufficient in width and number of chambers - the PVC window system is not suitable for this climate zone. Most often in winter, single-chamber double-glazed windows with a thickness of 24 mm fog up and freeze.
The installation gap is made incorrectly or the slopes are not insulated. Window installation technology involves constructing a multi-layer seam without tears or voids.

Scheme for using mounting tapes on windows
If the layer of mounting foam serving as a heat insulator is not covered with hydro- and vapor barrier tape or mastic, then it will collapse over time under the influence of moisture and ultraviolet radiation.

The sun destroys the foam
An assembly seam with damaged insulation cannot resist the penetration of moisture and cold into the room. In this case, not only the double-glazed window can fog up, but also the surface of the window and the slope.
The window sill installed under the window opening is too wide and blocks the radiator. Warm air will not be able to circulate in the plane of the window.

Numerous indoor plants or the presence of thick curtains further complicate the access of heat to the glass unit area. A zone of local high humidity may form here, and excess water vapor will fall on the glass unit.

The consequences of fogged windows can be very unpleasant. Increased humidity in the window plane can lead to constant accumulation of moisture on the windowsill, which becomes an excellent breeding ground for fungi, mold and harmful bacteria. The air in the room takes on a musty smell. Mold on slopes is difficult to get rid of.

Fungal deposits can cause an allergic reaction from the respiratory system and other diseases. In addition, foggy windows, puddles on the windowsill and fungal deposits on the slope are far from aesthetically pleasing.

Answers to the most popular questions

Why do the windows fog up even though it’s warm outside?

The appearance of condensation is affected not so much by the weather outside, but by the difference in temperatures outside and in the room. To prevent a window from “crying”, it needs maximum thermal insulation. Then temperature changes will not lead to the appearance of drops. Another possible reason is excess humidity in the room.

Why does fogging occur in winter and autumn?

Due to the temperature difference between indoors and outdoors due to insufficient thermal insulation of glass. If the insulation is poor, the surface of the glass cools, at the same time cooling the air, as a result of which moisture falls out of it, which it is no longer able to retain.

Why does water condense on glass in the morning?

Because at night, as a rule, the heating works more intensely, the radiators heat up more. At the same time, the lowest temperature outside is at dawn. As a result, before sunrise, the temperature difference between the street and the apartment is maximum, which leads to heavy condensation on the plastic windows.

The house and windows are insulated, but the glass still sweats. Why?

Perhaps the insulation was excessive. As a result, excess moisture simply cannot escape from the house. Its level rises, and the excess settles on the glass. Good ventilation solves the problem. Another reason is errors in insulation, especially at the junction of the wall and frame. The third option is that there may be too many plants on the windowsill with damp soil or water in the tray.

Which windows don't fog up?

Only those that are installed correctly and regularly ventilated. They should be located away from the outside of the wall. The seams should be well sealed and the ventilation valves should work properly. For middle and northern latitudes, two-chamber double-glazed windows and three-chamber profiles with a thickness of 60 mm or more are required.

Why does ice appear?

Because there is a bridge of cold. It could be a crack, a depressurized glass unit, or a gap between the frame and the sash. Another reason is that the single-chamber glass unit is too thin and there is not enough chambers in the profile, which is why the frame can become frosty in extreme cold.

How to wipe foggy windows?

Be careful, especially if the condensation has taken the form of frost or ice. A non-woven fabric that absorbs liquid well is suitable for wiping. This cloth will not scratch the plastic of the frame or glass and will gently remove ice crumbs.

Is fogging considered a defect according to GOST?

GOSTs and SNiPs consider situations when double-glazed windows fog up from the inside to be a definite failure. If condensation settles on the outside of the glass, the rules do not classify this case as a design defect.

Troubleshooting

If your windows are leaking, you need to determine the cause of the phenomenon. It happens that the situation arises as a result of placing a large number of indoor plants on the windowsill, which evaporate a large amount of moisture.

Window adjustment

You can verify what the cause is by doing a simple inspection of the entire window. The first thing to do is to check the correct adjustment of the valves and the degree of their locking . This is done as follows:

You can feel a strong draft by running your hand along the window.
Light a match or candle; if the light fluctuates, the seal is broken.
Paper is placed in the door and locked. You can pull out the sheet without any effort.

If deficiencies are found, proceed with adjustment. The sash is adjusted vertically and horizontally with screws located on the lower hinge.

To adjust the sashes, tighten the bolts located on the lower hinge

The degree of pressure is adjusted by eccentrics at the ends of the window, as well as by tightening the pressure plates.

Switching to winter or summer mode is carried out using eccentrics

Don't forget about seasonal window adjustments. To do this, turn the regulators with a marker inward in the summer, and toward the street in the winter.

Window sills

Windows often cry due to improper air circulation during the cold season. The reason lies in the wide window sills, which block the access of warm air masses to the surface of the glass unit.

In this case, to normalize circulation in the window sill, you need to drill several holes that will ensure normal heat access to the glass.

Holes in the window sill allow warm air to warm the glass

You also need to pay attention to the grilles covering the heating radiators; perhaps they also impede air exchange.

Slope finishing

If the window was installed incorrectly (leaky gaps, the frame has moved), then you should contact the installation company . Installers are required to fix this problem free of charge.

An independent attempt to seal the gaps may not correct the situation, since the double-glazed window was initially installed incorrectly.

Finishing and insulation of slopes prevents windows from fogging

The situation is different with slopes. If finishing has not been done, it must be done immediately, otherwise it will lead to complete destruction of the polyurethane foam in the gaps. To prevent windows from crying, it is best to additionally insulate them using heat-insulating material (mineral wool, polystyrene foam or polystyrene foam).

Accessories

Quite often, windows cry due to poor-quality or worn-out fittings. All mechanisms must function normally and smoothly close the sash while maintaining normal pressure.

Damaged seal must be replaced

The seal must be carefully inspected. It should be elastic, without tears or cracks. If there is damage and elasticity is lost, proceed to replace it.

Ventilation

Ventilation of the room must be approached very carefully. This is especially true for rooms with high levels of humidity (kitchens, bathrooms), where glass most often sweats in winter .

After all, plastic windows completely seal the room and make it difficult for air to enter from the street. The problem of air exchange can be solved in the following ways.

Check existing ventilation for blockages. This can be done by lighting a candle near the channel outlets. If the light does not deflect, then the hood does not work. The gratings are removed and cleaned until normal operation is restored.

However, in addition to the exhaust system, there must also be supply ventilation. This issue can be solved by installing ventilation valves on the windows.

Supply ventilation can be provided using the valve built into the handle

Today there are modern supply systems installed in the window handle; they do not spoil the appearance and provide a sufficient amount of fresh air.

By ensuring a normal level of ventilation, the problem of high humidity is eliminated.

Thermal insulation

Single-chamber double-glazed windows are used in most non-residential premises where thermal insulation is not so important. If such a double-glazed window is installed in a living room, it will not provide adequate heat conservation.

Thermal insulation of glass with film will not solve the problem of cold

The problem can be eliminated by insulating the slopes and applying an energy-saving film to the glass. But these measures will not ensure full heat conservation.

Optimizing humidity levels

As mentioned above, this phenomenon can be eliminated by ensuring normal ventilation of the rooms. However, if this does not help, then you can install moisture-absorbing devices under the window sill. Such cartridges are inexpensive, and their efficiency is quite high.

Recent renovations can increase indoor humidity. A large area of plastered surfaces evaporates a huge amount of moisture, which ventilation cannot cope with. This is a temporary phenomenon and as the walls dry, the humidity level returns to normal.

As a rule, these are the main reasons why windows cry in winter. Once they are eliminated, the situation will normalize and there will be no problems with fogging.