Why do plastic windows in your home sweat and cry?

Fogging of plastic windows: causes and solutions.

Plastic windows are very well adapted to any climatic conditions. It is also worth noting that they do not require special care and do not need painting, which greatly facilitates their operation.

But, unfortunately, like any thing, plastic windows have their drawbacks. The main thing, perhaps, can be called their periodic fogging. It is this problem that we will talk about today, and we will also try to find ways to solve it.

What is condensate

Condensation on PVC windows inside the apartment is steam, changing its state of aggregation to liquid at sub-zero temperatures. The presence of a small volume of liquid in gaseous form in the atmosphere is normal. However, how does condensation occur?

If a temperature difference of more than 30 degrees occurs inside and outside the building, the steam changes its state, becoming droplets of liquid. The activity of moisture formation is directly dependent on the thermometer readings and the humidity in the room. Here there is a “dew point” - this is the temperature of steam condensation, with one hundred percent humidity. In cold weather, the liquid freezes, turning into ice or frost.

There is a popular opinion that the tightness of PVC profiles is the main reason for the problem of crying plastic windows. Therefore, PVC is criticized, noting that old wooden frames did not have such a disadvantage. In fact, it was not the frames themselves that were “breathable,” but the cracks in their texture. Air exchange occurred through the gaps, which performed preventive functions.

In the summer months, condensation in an apartment on plastic windows is rare, because the external climatic conditions and those inside differ by only 2-5 degrees. But with the arrival of winter and frost, plastic windows sweat and leak profusely.

The so-called “dew” manifests itself in various ways:

1. Mostly in the kitchen.
2. Observe at a certain time of the day (morning or evening).
3. The glass itself remains dry, but puddles cover the window sills.

If you do not respond to the fact that plastic windows are constantly crying, the risk of fungus and mold in the room increases. And this worsens health, reduces performance and mood.

Reasons for crying double-glazed windows

When sometimes the glass fogs up from the outside, there is no great harm from this, but constant condensation should be alarming. If the windows are crying, what should the owners of the house do - deal with the root causes of the leaks. Regardless of the type of residential building, the following circumstances may be the causes of sweating:

1. Wrong choice of window frame according to the conditions of the climate zone: a thin double-glazed window will begin to cry in severe frosts or as the temperature in the house drops.
2. High concentration of moisture caused by infrequent ventilation, cooking and frequent washing. Manufacturers of plastic windows recommend maintaining the room temperature at 20ºC. Dampness can come from the basement or from the roof side for occupants of the first and last floors.
3. Error in the design or redevelopment: rooms are located far from the ventilation system, inefficient heating network. These reasons are beyond the control of PVC window installers.
4. Recent renovations in the house - freshly laid tiles, plaster or painting of surfaces for some time release moisture that settles on the double-glazed windows.
5. Adjustment of the valves - if it is disturbed, foggy areas appear where cold air penetrates through the seal.
6. Deviations from the regulations for the installation of metal-plastic windows: installation of a very wide window sill, incorrect filling of voids with polyurethane foam.

When fogging occurs inside a glass unit, this means it is depressurized. The likely reason lies in a manufacturing defect of the manufacturer or erroneous actions of an inexperienced craftsman. If a contract was concluded for the installation of a window and it provides a guarantee for such a case, replacement of the double-glazed window is carried out free of charge. Otherwise, you will have to purchase a new window at your own expense.

Main problems and solutions

For a long time now I have been carrying around the idea of ​​finally talking about the main reasons why plastic windows constantly sweat from the outside and inside in the apartment and what to do to fix the problem.

No. 1. Ventilation

Problem:

After installing a window profile, small smudges often appear on the window sills. They are caused by excess humidity, combined with insufficient heating of the inner glass. Humid and heavy air flows are not ventilated, but are stored in the shaft, after which they are transferred to the double-glazed window.

Oddly enough, plastic windows sweat not only in apartments, but also in old private houses. Here the ventilation system is focused on wood profiles. It does not serve completely sealed plastic structures effectively.

Solution:

the functioning of the ventilation system should be adjusted. First check if there are any problems with its operation. You can do this: bring a lit candle (match, lighter) to the exit channel of the dilapidated mine. A burning light is a sign that everything is in order. If the flame fluctuates or dies out, there is a problem.

The second option for checking is to bring an A4 sheet of paper to the shaft. If it is attracted by the air flow, the system functions without failures.

What to do if the plastic windows at home sweat? If you discover that the system is not operating correctly, clean it and remove any dirt.

An acceptable option is to equip the window unit with a supply ventilation device. It will help create natural circulation of air masses and cope with condensation.

No. 2. Thermal insulation

Problem:

Often, single-chamber double-glazed windows in residential premises do not retain heat effectively enough. This is why plastic kitchen windows in the house often sweat. After all, it is there that the owners do not consider it necessary to install expensive two- or three-chamber double-glazed windows.

Solution:

Insulating the space next to the block with plasterboard will help increase the thermal insulation of the structure. It is necessary to finish the slopes, facade walls, and the area under the window sill. The glass is protected with a “third glass” film with an energy-saving function. If there is no result, purchase a double-glazed window with two cameras.

No. 3. Windowsill

Problem:

The reason for the appearance of condensation on the window is that, due to its size, the window sill interferes with the full movement of air masses. Heat does not reach the double-glazed window, so if it is cold outside, moisture is observed.

Solution:

Alternatively, reduce the width of the window sill. Then the air heated by the radiator will flow freely to the unit, solving the problem. The second way is to pull out the battery. If there is a screen mounted on it, it should be removed. You can also drill holes in the structure to allow warm air flows to enter. An air vent is installed through the window sill; its purpose is to conduct air heated by the radiator to the block.

Why else does condensation form on plastic windows? Green plants in pots can also cause trouble, especially if there are a lot of them. Flowers become obstacles to the normal movement of air flows and increase the level of dampness. The pots should be rearranged. Or install a valve for slot ventilation. It will help stabilize the humidity level without freezing the “green residents”.

What else should you do if plastic windows at home very often sweat due to the width of the window sill? A convection screen is mounted above the radiator. This is a device consisting of grid plates. Installed obliquely (angle 30-60° to the surface). The screen lifts the air masses heated by the battery and moves them towards the block.

No. 4. Double-glazed window

Problem:

Possible reasons why plastic windows sweat in cold winter associated with double-glazed windows:

1. Incorrect hardware mode setting. There are two of them - winter and summer. If replacement is not done in a timely manner, condensation may appear. The solution is to adjust the windows on time.
2. Rare ventilation. The solution is to ventilate the room daily for 15-20 minutes.

Solution:

You should take a responsible approach to choosing PVC windows. For rooms and loggias, it is better to choose double-glazed windows with two chambers. A model with one camera is suitable for a room adjacent to a glazed balcony. It does not need additional insulation.

Cheap glass to save money is a bad choice; they are not able to retain heat well. This is the reason why windows sweat profusely. Choose low-e glass.

Buy “warm profiles” - with 4 or 5 chambers and an installation depth of 70 mm. Which windows never sweat? First of all, high quality and installed without errors.

Violation of tightness

Problem: often the formation of condensation inside the window is stimulated by depressurization. Perhaps the glass unit is defective. In this case, contact the technicians who did the installation and request a replacement. There is no need to dismantle the profile itself; it is enough to replace the double-glazed window.

Solution:

1. Remove the glazing bead.

2. Remove the glass unit, find the area of ​​depressurization, and clean it.

3. Dry the glass, you can use a regular hairdryer.

4. Treat the damage with a protective polymer composition.

5. Restore the structure.

The second reason why windows inside the glass unit sweat is cracks or chips. They are often small, visually almost invisible, but cause great harm, especially in winter. Finally, additional accessories, such as blinds mounted on the frame, also cause problems. Solution: treating the holes with sealant.

No. 5. Fittings and seal

Problem:

Often condensation on PVC windows appears in cheap or broken fittings.

Solution:

the mechanisms must work properly. If necessary, the damaged element should be replaced.

Problem:

The reason why plastic windows sweat may be wear of the rubber seal. It is recommended to change it every 5 years; if you forget about it, the seal can cause a problem.

Why else do plastic windows regularly sweat and cry? Thick curtains, blinds, and roller shutters interfere with the normal movement of warm air currents.

Solution:

Do not close the window completely; allow air to move freely.

No. 6. Slopes

Problem:

PVC windows sweat a lot, mold appears on uninsulated slopes

Solution:

It is recommended to insulate the structure outside and inside. For this, heat-insulating materials like penoplex are selected. It is impossible to plaster these elements without preliminary insulation. It is advisable to “hide” the slope behind the PVC frame. These are the most popular and effective methods to eliminate foggy windows.

No. 7. Installation errors and poor-quality windows

If windows sweat heavily from the inside, that is, between the panes, this is often due to neglect of the PVC profile installation technology.

I will name the main mistakes of installers:

1. Poorly sealed cracks. Some “specialists” save silica gel, located between the glasses and designed to protect against dampness. If it is not enough, the window will fog up from the inside.
2. Blowing through the masonry due to the seams in the wall.
3. Cold bridges are areas where PVC comes into contact with the street side of the wall.
4. If the installation is done incorrectly, various troubles may arise - condensation, blowing from cracks, heat leaks.

What to do if you notice in your home that the windows are sweating from the inside? Contact the installation company with a complaint. Most likely, the structure will be replaced.

Reasons for freezing of plastic windows

One of the main reasons for freezing of plastic windows is the humidity in the apartment. Excessive humidity primarily affects the appearance of condensation on the glass unit. With natural air exchange, moist air exits through the ventilation holes; in the absence of ventilation, it settles as condensation on the glass. Poor ventilation is affected by the high tightness of plastic windows, which does not allow outside air to pass through; in addition, a large amount of exhaled air has nowhere to go, which increases air humidity and leads to fogging of double-glazed windows.

At the same time, freezing of plastic windows occurs due to incorrect installation design and insufficient tightness.

A large gap between the window opening and the plastic window frame can disrupt the tightness if the installation seam is single-layer. In this case, the polyurethane foam may fall out over time or will not absorb moisture. Poor quality installation seam or improper finishing of slopes also affects freezing of frames around the perimeter of the window.

Poor quality, outdated seals or the absence of vapor barrier and waterproofing tapes cause the window to blow out.

The use of poor fittings leads to sagging window sashes over time. Not tightly adjacent to the frame, they form gaps through which air from the street penetrates. This promotes additional cooling of the glass and condensation, respectively, freezing.

Freezing of plastic windows can be caused by a significant deepening of the frame in the opening when replacing old windows with plastic ones. The thickness of the PVC window frame reaches up to 120 mm, and the approximate depth of the opening is 70 cm. This means that the warm air coming from the battery, which is located under the window or may not be present at all, does not reach the double-glazed window. Thus, an unheated area is created in the window sill area, and in severe frosts the resulting condensate freezes. To prevent this problem, you need to choose a window with the thickest profile, which will reduce the recess.

Insufficient heating of the room during the cold season and poor air circulation affect the occurrence of condensation and freezing of PVC windows. A wide window sill affects air circulation in the room. Flower pots and curtains touching the windowsill can block the flow of heat coming from the radiator or radiator. Therefore, it is necessary to take this issue seriously and consult with specialists in advance.

Careless handling and neglect of simple window care rules also contribute to glass freezing.

Why do the windows on the balcony sweat?

Let's look at why windows on loggias and balconies sweat. After installing the PVC profiles, the microclimate in the extension changes. The tightness of the structure means that air flows cannot move naturally.

Humidity norm on the balcony

If the plastic windows on the balcony sweat a lot, the key reason is the high level of humidity. When the thermometer reads +20 degrees, the permissible humidity is 45-55%. However, if the outdoor indicator drops from -15 degrees, condensation will appear in the room. Therefore, according to building codes, the humidity level varies from 40 to 45%. If you follow this rule, the windows will not cry in winter.

But it also happens that high humidity penetrates into this area from the room adjacent to it. The tightness of the structure becomes an obstacle preventing water vapor from escaping. Outbuildings where flowers or seedlings are grown are at risk. They create increased dampness, so windows regularly sweat and leak.

Glass temperature

The factor that causes condensation to appear on plastic balcony windows is the low temperature of the internal glass of the structure. The minimum acceptable value is 5.2 degrees. In this case, condensation does not occur. External temperature – up to -20 degrees. Cheap double-glazed windows cannot cope with the load, so they can become covered with drops of moisture from the inside.

A special compact thermometer equipped with sensors will help you measure the indicator. It is impossible to determine the temperature by applying a thermometer to the surface - the error is very high.

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How to reduce the likelihood of crying windows?

Preventing a problem is always easier than fixing it. To prevent your windows from crying, when choosing windows, take into account the operation of ventilation and heating in your home.

At the order stage, “turn on”:

• installation of a “warm” 2-chamber double-glazed window (energy-saving glass, “warm” spacer frame, inert gas inside the double-glazed window);
• ventilation devices, including micro-ventilation;
• window profile with a thickness of 70 mm and from 5 internal chambers;
• a window sill that does not cover the battery by more than 50%;
• installation in accordance with GOST using special tapes - vapor barrier and vapor permeable.

During use:

• carry out regular ventilation (at least 3-4 times a day). It is recommended to open the window in the kitchen during cooking for micro-slit ventilation;
• after repairs, carry out intensive ventilation and drying to normalize humidity;
• monitor the operation of heating and ventilation;
• pay attention to ensure that curtains and blinds do not obstruct the passage of warm air to the window;
• use additional heaters when the temperature of the central heating radiators is insufficient.

When windows cry, this is a dangerous signal - the microclimate in the house is not in order. High humidity threatens the appearance of mold on window slopes and walls, and in the future – pulmonary diseases for residents.

Simple actions will solve the problem: regular ventilation, installation of warm and sealed windows, use of window fittings with micro-ventilation, for example, Roto NX *, which has a built-in slot ventilation mechanism.

What are the consequences of condensation on windows?

The appearance of condensation can be called a serious problem. The light transmittance of a fogged glass unit decreases. The room becomes damp, fungus and mold spots form.

Microorganisms in a favorable environment begin to multiply, causing damage to finishing materials and destroying the polyurethane foam. They are harmful to furniture and textiles. The plaster begins to deteriorate, and dark spots of moisture appear on the wallpaper. The PVC profile loses its thermal insulation characteristics. Condensation is also harmful to people:

1. Mold increases the risk of asthmatic lesions and allergies.
2. Constant dampness worsens the body's defense reactions.

Such unhealthy conditions are especially harmful for children.

How to treat windows

Let's consider what to do and how to treat the glass surface of plastic windows if they sweat from the inside.

The simplest way is to treat surfaces with a composition recommended by the manufacturer. It does not reduce the light transmittance of the structure. But it forms a film on the surface for protection.

What else can you do if your windows are sweating and leaking a lot? The second method is treatment with an aqueous solution. 1 tbsp dissolves in 5 liters of liquid. salt and then filtered. Used for glass processing. If stains remain, use a soap solution. Then wipe with clean liquid and wipe dry.

An alcohol solution is an excellent way to prevent PVC windows from sweating, which is suitable for a cool room. “Second” is also used to treat double-glazed windows: the spray is sprayed onto the glass, then completely wiped off with newspapers. Another composition for processing: alcohol + glycerin (10 to 1). Windows are washed with clean water and wiped. Then apply the composition without rinsing off.

Folk remedies for condensation

Traditional methods should be classified as protective measures . They do not always allow you to completely get rid of the problem. More often used as a temporary solution to a problem before starting main actions. For example, during the period when a new window is expected to be delivered or before the necessary parts are purchased.

Folk remedies can be used for several weeks or even months. List of methods and components:

1. Medical alcohol . A mixture of alcohol and glycerin should be prepared in a ratio of 10:1. To prevent fogging, it is enough to wipe the glass with this composition 2 times a month. Another option for using alcohol. It is suitable for cold rooms. You need to add a little alcohol to a container of water and apply it to the glass.
2. Toilet soap . Using a dry bar of soap, draw a fine mesh pattern on the glass. Rub with a clean cloth until shiny. The fabric should be cotton or microfiber.
3. Salt . Fill a cloth bag with dry salt. Place between window frames. Change as moisture is absorbed.

4. 
   Decorative candle . Place several candles on the windowsill and light them. The method is applicable when glass fogs up from inside the room. Candles should burn for several hours.

5. Ready-made product “Second” + several newspapers . Apply the spray to the foggy area of ​​the window and spread over the entire glass. Use newspaper to remove the product, rubbing the glass until it shines.

You can choose several methods to alternate between them.

How to adjust windows

Considering how to get rid of condensation on PVC windows, we will also talk about setting the design mode.

The first step is to check whether the problem is actually caused by a maladjustment of the valves:

1. Strong draft near the window unit. You can feel it if you run your hand along the frame.
2. Light a match and see. The movement of the flame is a sign of a seal failure.
3. Place an A4 sheet of paper in the door and lock it. Removing the leaf is quite easy.

If the problem is urgent, you should proceed to setting up the mechanism.

Procedure for switching to cold mode:

1. Wash the frame, remove dust, treat the mechanisms.
2. Lubricate the fittings.
3. Open the sash, find the eccentrics. Look at the set clamping force on the trunnion: the closer to the center it is located, the tighter the rebate.
4. Using a hexagon, turn the eccentric. The round one scrolls outward, the oval one moves to a horizontal position. If the element is round with an offset center, the wide side rotates into the flat.
5. Scrolling is carried out around an axis, the maximum rotation for winter mode is 180 degrees.

The procedure for setting the fittings is simple; even a beginner can handle it.

Tips for eliminating condensation (humidity)

Air humidity is the main reason why plastic windows in an apartment sweat from the inside in winter. Humidity is formed from two sources: a small part comes with air from outside (during supply ventilation). The second is produced indoors when people breathe, wash, cook, or operate gas equipment.

The main reasons for leveling up include:

1. Problems with the hood.
2. Refusal to ventilate or do it from time to time.
3. Insufficient heating of the room.
4. A large number of plants or constantly drying laundry.
5. Finishing and construction “wet” work.

All this causes new plastic windows to sweat a lot. When solving problems, many make mistakes that only aggravate the situation. First of all, they refuse to ventilate. The solution seems quite logical - if it’s cold outside, the heat should be kept inside by refusing to open the windows and transoms. In fact, ventilation should be organized while simultaneously increasing the heat supply using electric heating devices.

The second mistake is the desire to completely seal the room, to close all the holes and cracks. As a result, water vapor will not be able to leave the room, and the problem of windows in the apartment that cry will only get worse.

For closed spaces, especially non-residential ones, heat guns are used. They move water vapor to the coldest places, where condensation forms. It is important to remove flows outside, so ventilate the room intensively.

Finally, let’s look at some additional tips that will help you know what you need to do to stop your windows from sweating:

1. All cracks must be carefully sealed.
2. If there are summer and winter settings, change them with the onset of the corresponding season.
3. Decorative candles will help reduce humidity in the con area. Several pieces are installed on the windowsill and lit. However, with this method, pay attention to fire safety. A candle can only burn if an adult is present in the room.
4. Use household fans. The device is connected to the network and directed to the window unit. The operating time is 10-20 minutes, this is enough to solve the problem if condensation forms on the windows in the apartment.
5. The air temperature in the apartment in winter is between 22-25 degrees.
6. Cover the aquarium with a lid.
7. A nichrome thread running around the perimeter of the block is another unusual way to solve the problem. It operates under a voltage of 12-14 V, while protecting the structure well from moisture.

Ventilation

If condensation forms on the windows in the apartment, measures should be taken. To ensure that your living space has a normal microclimate with optimal humidity (45-60%), ventilation should be organized every day. 10-20 minutes will be enough. This applies to both rooms and balconies. There are the following ventilation methods:

1. Rotary mode of opening the sash. Provides the most efficient air exchange. In severe frost it is better not to use.
2. Tilt mode. It allows fresh air flows into the room well. But it protects against freezing. This kind of ventilation is another option for dealing with weeping windows.
3. Micro-ventilation. The door opens only 2-3 mm, air penetrates into the room, the risk of freezing is minimal (the temperature will drop by 1-2 degrees). Airing for several hours is acceptable.
4. Supply ventilation with valve. The device is mounted on a window. Ventilation is carried out on a constant basis, even if the sash is closed. The indoor microclimate improves. It has virtually no effect on the heat and sound insulation characteristics.
5. Wall supply valve. Installation is made into the wall. The device operates without an electrical network, air continuously flows into the room. To protect against dust and dirt from the street, it is equipped with a mesh.

To avoid condensation on the windows and for ventilation, you can purchase a breather - a device that performs ventilation and heats air flows. The device is wall mounted and has compact dimensions.

To summarize why windows sweat inside and on the outside of a double-glazed window, we can highlight - choose a high-quality profile, install it in full accordance with the installation technology and follow the operating rules.

What to do when windows leak

The easiest way to not have leaking plastic windows is ventilation, in which humidity and temperature are evenly distributed throughout the room.

In different conditions, different ventilation methods are chosen.

1. Micro-ventilation.

This is a function provided by the window design. It is enough to set the handle to the upper position, and the sash will move a short distance for free access of air from the street.

1. Using a comb.

A comb can be bought at a hardware store.
This is an additional fitting that limits the angle of inclination of the sash. The inclination is selected in steps up to 60 degrees. A hook is used as a limiter, which is mounted on the frame.

1. Installation of climate valve.

This is an additional device that is mounted on the top of the frame.
It is connected to the street air and controls its flow into the room. The air flow is set manually or automatically. The ventilation process is automatic and controlled by the humidity level in the room. Other ways to prevent current windows from appearing include:

• installation of an air conditioner with a split system to maintain standard humidity and temperature;
• increasing the glass area when replacing windows. Large glasses warm up better and cool down longer;
• placing a convection screen on the windowsill that directs warm air onto the glass;
• installing a fan in the window opening to move air;
• glass treatment with anti-fog for cars;
• equipping glass with low-voltage electric heating, like in a car;
• use transparent and thin curtains that cannot block the movement of air masses. In addition, they will be a moisture filter;
• do not crowd the window sill with bulky objects, flowers, containers with liquid;
• Place a container of lime or salt on the windowsill. These compounds absorb moisture and dry the air;
• contact window installers if there is a suspicion of poor-quality products or violations during installation.