Why do plastic windows on balconies and loggias fog up, what to do if condensation appears and double-glazed windows cry inside and out, consequences, mistakes

Double-glazed windows installed in residential and public premises significantly increase their energy efficiency and prevent heat loss.
When using a translucent structure, a number of problems may arise due to manufacturing defects or incorrect installation.

Many owners of apartments and private houses wonder where condensation on the plastic windows of balconies and loggias comes from.

Causes of condensation

Plastic windows installed on balconies or loggias fog up when any of the following situations occur :

In the case of heating a cold room and insufficient energy efficiency of window structures.
If there is no air exchange on the balcony for a long time.
If the balcony is used as a mini-greenhouse. Fresh flowers must be watered, which causes a large amount of water vapor to be released into the room.
When certain climatic conditions occur during the cold season, if the temperature on the balcony significantly exceeds street parameters.
In the absence of a vapor-permeable membrane that provides natural ventilation of windows and prevents the formation of condensation.
If there are gross errors made during the installation of window units.
In case of a manufacturing defect resulting from the assembly of frames or installation of double-glazed windows.
If there are cold bridges in the places where the window profile is attached to the enclosing structures of the balcony.

Important. The most common cause of condensation is the installation of single-glazed windows or single-chamber double-glazed windows.

Such structures have insufficient resistance to heat transfer, as a result of which, when warm air enters the balcony space, a dew point forms on the glass, which leads to fogging.

The role of correct diagnosis of the problem

To carry out proper repairs or prevention, it is necessary to determine the true cause of condensation on balcony windows. If the technician understands why the window is fogging up, this allows him to do the following :

Change the sealing tapes installed during installation.
Recommend that the owners of the premises take additional measures to ensure ventilation of the space being used.
Carry out repair work or partial replacement of double-glazed windows.

If the diagnosis is incorrect, all subsequent measures to correct the violation may not bring the expected result.

Selection of double-glazed windows for a balcony

The owner decides which windows to install, focusing on his own preferences and financial capabilities. But often the price category turns out to be the main determining factor, as a result of which the glazing is characterized by insufficient thermal efficiency.

To achieve high-quality glazing and ensure a comfortable microclimate, you need to find out some nuances before starting work:

the purpose of the balcony - if it is a storage room, windows with low thermal efficiency will suffice, an office or a winter garden - you will have to choose expensive structures;
climatic conditions - the harsher the winter, the more multi-chamber the double-glazed window should be;
insulation - the level of moisture accumulation depends on the quality and quantity of insulation materials, for example, mineral wool insulation can absorb excess water, releasing it later as needed, and polystyrene foam does not collect moisture.

Advice! Expensive double-glazed windows increase the cost, but you should not save. It is possible to slightly reduce costs on the interior decoration of the room by choosing inexpensive but high-quality facing materials - plastic, unedged boards, etc.

Is it possible to solve?

The problem of window fogging can be solved, regardless of the cause of the problem. To prevent the formation of condensation, the following basic techniques can be applied :

Replacement of translucent elements with energy-efficient double-glazed windows.
Organization of air heating or ventilation on the balcony, which at the same time helps to expand the functionality of this room.
Installation of energy-saving glass, or the use of modern methods of heating cold surfaces.

Each chosen method entails certain work, as well as the need to purchase consumables.

Important. Before deciding to carry out repair work, it is necessary to draw up a plan, taking into account all upcoming expenses.

When is it impossible without radical measures?

In some cases, simple repairs with minimal costs will not be possible , and the master decides to completely replace the window structures, or to carry out additional work in the space of the balcony or loggia:

If there is single glazing on the balcony, installed in cold profiles with a minimum thickness.
In the absence of hermetically sealed locks that ensure a tight fit of the frames in the vestibules.
If there is heating on a balcony with inefficient windows.
In case of freezing of the glazed contour from the outside, on a reinforced concrete floor slab without thermal liners.

In such situations, only dismantling window structures and replacing them with new, energy-saving frames with double-glazed windows can help.

How to prevent windows from fogging up?

Finally, let’s look at a few measures to prevent windows from fogging up:

Before each heating season, the condition of the seal should be inspected. If deformed, it must be replaced.
Windows must be adjusted correctly, as loose and uneven fit of the frame also causes fogging.
You should not place many flower pots on the windowsills. In winter, it is better to move them to another place.
If the glass fogs up and this problem cannot be eliminated, the window can be treated with glycerin, alcohol or vodka. You can also use special anti-fog car spray.
To prevent the glass from fogging up on the balcony, it should be insulated. This will make not only the balcony warmer, but also the room to which it is adjacent.

Following the above measures, recommendations and tips will effectively solve the problem of window fogging.

Solutions

To eliminate the problem of fogging of the inner surface of the glazing of a balcony or loggia, experts suggest carrying out various measures :

Insulation device for the cold circuit on the façade side.
Additional thermal insulation of the balcony on the room side.
Adjustment or repair of fittings to ensure tight fit of the sashes to the main frame profile.
Installation of climate control equipment that provides heating, ventilation and dehumidification of indoor air at the same time.
Replacement of double-glazed windows, if the window profile allows the use of translucent elements of different thicknesses.
Full replacement of window structures.
A device for electric window heating based on the principle of a heating filament, as is constantly done for car windows.
Sealing of window structures in case of incorrect installation.
Treatment of glass surfaces with specialized chemical compounds.
Installation of a wide window sill and design of slopes with additional insulation with polyurethane foam.
Temporary thermal insulation of the glazing contour during the cold season.
Changing the technological purpose of the balcony space to reduce humidity levels.

Important. In some cases, installers recommend carrying out comprehensive insulation or insulation, simultaneously with the installation of internal engineering systems in the room.

Sweating from inside the room

If there is condensation on the glass, the simplest solution would be to carry out repair and preventative measures on the premises. To do this, you need to perform the following algorithm :

Installation of a duct fan in a balcony space with air ducts of the design cross-section.
Replacing the sealing tape with a new product with a vapor-permeable membrane.
Organization of additional insulation of the junction of the frame and building structures.
Replacing single-glazed windows or single-chamber double-glazed windows with more energy-efficient, double-chamber products.
Installation of drainage channels in the profile through which excess condensate is removed.
Carrying out servicing of the fittings of each opening sash with its adjustment and performance testing.
Arrangement of slots for ventilation, or installation of supply valves in the enclosing structure of the balcony.
Insulation of balcony fencing with installation of effective insulation.
Installing a heating radiator or air conditioner on the balcony after installing a warm circuit.

Note. The final scope of work is determined only after a complete diagnosis of the causes of condensation and the development of a technological map.

If the windows cry in winter

During standard use of the balcony without changing its functional purpose, the glass begins to fog up only in the cold season. To get rid of this problem, the owner of the residential premises needs to take the following measures :

Temporary gluing of seams, joints and gaps with energy-saving materials.
Installation of a portable heater with a drying mode.
Organization of periodic ventilation of the room to allow circulation of air masses.

In winter, the owner of the premises can take emergency measures that prevent the formation of condensation only temporarily. All major work must be done in the warm season.

Useful tips

Craftsmen who install double-glazed windows often give customers useful advice, following which will help prevent the windows of the balcony frame from fogging up:

Do not change frames during cold weather. The structures must be installed at positive temperatures.
Try not to keep the doors tightly closed. If the weather permits, it is better to set them to micro-ventilation mode.
If possible, install a battery indoors. When it already exists, do not cover it with a wide window sill or pieces of furniture and curtains.
Household fans will help quickly restore the indoor microclimate. They won’t solve the problem, but they will help get rid of “crying” glass for a while.
If the warranty period for the windows has not expired and the glass is sweating, do not hesitate to contact the company that carried out the installation. Correcting the defects in her work is her direct responsibility.

Observing the temperature regime will also help to avoid the appearance of water flowing down the glass window frames. Maintaining the indoor microclimate in the range of +18...+20 °C will allow you to forever forget about what fogged glass looks like.

Difficulties and errors

When carrying out repair and restoration work for window structures to get rid of condensation, many consumers make gross mistakes, which lead to the need for costly measures.

To avoid this, experts often recommend that beginners pay attention to some important nuances :

You should immediately purchase energy-saving PVC profiles and double-glazed windows.
If there is condensation between the glass panes inside the glass unit, you must immediately contact the manufacturer, as this indicates a gross violation of the technology when gluing elements with butyl sealant.
For installation, you need to contact professionals, and when doing the work yourself, it is recommended to study master classes and follow the technological map.
Before installing warm PVC windows and organizing balcony heating, you should insulate the building structures from the outside in advance.
When sealing installation gaps, you should use only high-quality materials from well-known manufacturers.
It is recommended to install supply valves on each PVC balcony window to ensure constant slot ventilation.
After installing the windows, you should immediately install window sills and slopes to increase the heat transfer resistance of the translucent structure.
In the case of growing flowers on the balcony, it is recommended to purchase an additional dehumidifier that removes water vapor from it.

Important. If these recommendations are ignored, any preventive or emergency repair work may not give the expected result, and condensation will form again.

Prevention measures

Often, even in cases where the installation of frames and work on insulating the balcony are carried out correctly, the glass still begins to leak. To prevent this from happening, preventive measures should be followed, the main goal of which is to maintain a normal microclimate in the room.

To prevent moisture from appearing on glass, it is recommended:

Remove flowerpots from the room.
Dry clothes only with the windows slightly open.
Maintain proper ventilation.
Avoid sudden temperature changes.
Check the condition of seals and fittings once every six months.
Install a canopy to protect the frame from snow and monitor the operation of the drain.
Seal all cracks and install slopes.

Why does it need to be fixed?

Eliminating the problem of condensation on the glass surface of translucent structures of balconies or loggias is a mandatory procedure that must be resolved when the first signs of violations appear.

Measures to prevent fogging allow you to achieve the following positive effect:

Increasing the energy efficiency of the space being used.
Elimination of premature destruction of interior finishing elements due to increased dampness.
No fungal deposits on plastic, wood or stone surfaces.
Avoiding freezing of structures during the cold season.
Increasing comfort during the operation of premises.
Improved viewing panorama with clean translucent structures.

If there is condensation, the balcony or loggia cannot be operated normally, which causes many problems for the owner of an apartment or private residential building.

Possible consequences

If you do not correct the problem with fogging of the window surface, every resident of an apartment or private house will face a number of unpleasant consequences :

A feeling of stuffiness in the room, in the absence of movement of air masses and a high concentration of water vapor.
As the amount of condensation increases, excess moisture will begin to destroy the balcony finishing elements.
If condensation gets on the profile when the sash is open, ice may form on the plastic. This leads to the impossibility of closing the window tightly, as well as to the expansion of frozen liquid and distortion of the sash.
If there is constant moisture in the room, mold begins to form on most surfaces due to the proliferation of bacteria.

Important. Simply ventilation will not save the situation either, since in this case heat loss increases, and street dust or precipitation constantly enters the room.

A little theory about dew point

Dew point (DP) is the temperature value at which vapor in the air reaches a state of saturation, as a result of which it begins to condense. This value directly depends on the relative humidity and air temperature.

To understand what we are talking about, consider the following table:

According to the data given, at 25 °C and a relative humidity of 60%, the dew point will be 16.2 °C. That is, condensation will form on objects with a surface temperature of 16.2 °C and below. You can notice a trend: the higher the humidity indicator, the closer the TC is to the actual temperature in the room.

If the dew point exceeds 20 °C, a person begins to experience discomfort as it becomes stuffy. And situations when the temperature approaches 25 °C pose a serious danger for people suffering from heart and respiratory diseases. Therefore, it is not recommended to visit countries with tropical climates with such diseases.

Various dew point indicators are perceived by humans as follows:

< 10 °C – slight feeling of dryness;
10-15 °C – comfortable;
16-17 °C – possible feeling of humidity;
18-20 °C – uncomfortable for most;
21-24 °C – very stuffy;
25 °C and above is extremely uncomfortable and life-threatening for heart patients and asthma patients.

For your information! The highest dew point of 35 °C was recorded on July 20, 2012 in Iranian Jask. On this day, the air warmed up to 36 °C, and the relative humidity was 95%.

Dew point is the most important indicator not only for human well-being, but also for construction projects. If this parameter is calculated incorrectly, condensation will form on the surface, which will accelerate the corrosion of the material. Therefore, builders are required to take the vehicle into account when insulating or painting a structure.

Condensation is the main problem of insufficiently insulated construction projects

Some good advice

What product can be used to prevent or reduce window fogging?

We recommend watching a video about effective methods of combating window fogging.

There are also other folk remedies:

For 4 liters of water take 1 tbsp. l. table salt, stir, strain. Apply the solution to the glass and let dry.
Mix glycerin and alcohol in a ratio of 1:10. Apply the mixture to the glass and let it dry.
Use special chemicals against “crying windows”.

Why windows on balconies or loggias fog up, and how to fix it once and for all

The cause of condensation and fogging of windows on double-glazed windows occurs after the installation of new plastic or wooden glazing. To solve the problem, you need to identify condensation and fogging, and then eliminate it. It is also necessary to understand the nature of the origin of the condensate itself.

In our article we will find out why the windows on the balcony sweat and find an effective solution to this problem.

Forced ventilation of the loggia

Back in Soviet times, there were exhaust fans that were mounted in the vents of window frames. They had a low-power, noisy motor and a thin plastic plate - a plug that perfectly let the cold through even when closed. With the variety of modern ventilation devices, proper ventilation of the loggia is not problematic.

The simplest models of forced ventilation are the same wall or window flow valve, equipped with a simple fan. More expensive models can operate in two modes: exhaust and pressure. In addition, they are equipped with protective and inertial grilles and filters. The most expensive models of forced ventilation systems are equipped with recuperators. These devices extract warm air and release it outside while drawing in cold outside air. Inside the device, both air flows enter the heat exchanger, where, without mixing, warm air from the room heats the cold air coming from the street. Such devices have a wide range of functions and have a number of undeniable advantages:

ease of installation. The main work does not differ from the installation of a large-diameter supply ventilation wall valve;
actively filters external polluted air;
low noise level;
additional heating of the air flow;
Loggia ventilation fan with flap
additional anti-frost function (option not included in basic supplies and must be ordered additionally);
automatic rise in temperature of the heating element by 3-5 degrees C at night;
efficiency;
Ease of use. There is a built-in speed and temperature controller and a remote control programmer.

Flaws:

high price;
Requires connection to an electrical outlet.