7 tips on how to insulate plastic windows with your own hands

8 min

Why insulate plastic windows? This reasonable question arises, for sure, for all owners of modern sealed structures, because the manufacturers sold us a perfect product with perfect thermal insulation. Installation errors, improper operation, house shrinkage and time can play a cruel joke even with the highest quality windows. Do not rush to change the entire structure – you can try to insulate plastic windows with your own hands. It is simple and short-lived. We deal with the weak points of modern windows and learn how to eliminate them.

# 1. Why do plastic windows need insulation?

In the first years, well-made and installed plastic windows will certainly be a reliable barrier to cold air, drafts and noise. Over the years, of course, problems can appear, and often the user himself is to blame. In case of improper installation, various defects can make themselves felt in the first season.

The most common reasons for additional thermal insulation of plastic windows:

  • installation performed in violation of technology;
  • shrinkage of the building, which is especially typical for new buildings;
  • wear of rubber insulation. Responsible manufacturers and installers inform the user about the rules for caring for the rubber seal, but few follow the rules and regularly inspect the condition of this structural element. Lack of proper care leads to an accelerated process of thinning and drying out of rubber, the appearance of microcracks in its structure, the result is a decrease in the density of adhesion to the frame and deterioration of thermal insulation;
  • incorrectly set slopes.

A window of poor quality or with technical characteristics inappropriate to climatic conditions will also not be able to provide normal thermal insulation, therefore it is so important to be able to choose the right plastic window and immediately decide on a suitable glass unit.

# 2. Identifying Weaknesses

In order to effectively insulate plastic windows, you must first figure out where the tightness is broken. Immediately from the list of suspects, only the frame can be deleted: multi-chamber plastic is a good heat insulator, it does not dry out, unlike wood.

Cold air can penetrate such structural elements:

  • clamping elements that tend to loosen over time;
  • the detached glazing bead that holds the glass unit;
  • worn out seal;
  • polyurethane foam, if it was applied in violation of technology;
  • windowsill;
  • slopes.

A double-glazed window rarely causes a violation of thermal insulation (the exception is its depressurization), but it can also be additionally insulated. “Extra” warmth in winter will not hurt.

It is easy to identify leaking elements of the window – just hold your palm along and across the entire structure, and you will feel that it blows decently in some places. Some people advise using a lighter for this purpose. If you light a flame and hold it around the perimeter of the window, keeping a safe distance, then it will tilt in those places where there is even a slight draft. Be extremely careful with this method!

As a rule, work on the insulation of a plastic window can be done by hand. The exception is when it is necessary to insulate the slopes from the outside, and the apartment is located above the second floor. It is necessary to be prepared that complex insulation may be needed if several zones of warm air leaks are found, but first things first.

No. 3. Debugging the pressure mechanism

Shrinkage of the house and weather factors can lead to slight distortion of the window sashes and slight deformation of the sealing gum. This leads to a deterioration in thermal insulation, but in this case, the return of the former tightness is a matter of a couple of minutes, however, knowledge of the design of a plastic window and skills in working with tools will be needed.

The regulation of the clamping mechanism can be carried out using special eccentrics located along the perimeter of the flaps. In order for the sash to fit more tightly, the eccentric must be turned clockwise using a 4 mm Allen key. Focus on the serif located on each such element. When it is directed towards the street, the clamp is weakened, towards the sealant – it is strengthened. The video shows everything well.

Sometimes a simple regulation of the hinges, which also have their own mechanism responsible for the pressure density, helps to insulate a plastic window. Here the regulation is carried out using a hexagon. One should be guided by a simple rule: if the tongue is strongly extended, then the sash fits well. To pull it out, you need to turn the hexagon counterclockwise if the hinges are on the left, and clockwise if on the right.

The situation is even simpler with glazing bead. It is enough to pry the old gone glazing bead with a thin spatula, and replace it with a new one, which can be bought in the same company that sold and installed the windows for you.

After adjustment, check if the tightness of the structure has improved with the palm of your hand or a lighter. If everything is done correctly, and the draft still walks, then you will most likely have to change the seal.

No. 4. Replacing the seal

Ideally, a rubber seal can last long enough, but certain conditions must be met. According to the rules for the operation of plastic windows, the seal must be regularly lubricated with special substances, but which of us does this? So it turns out that after 5 years the rubber dries up and starts to let the cold breeze from the street. The problem may be in the seal, which is located under the glass, or in what is along the contour of the sash. Replacing the seal in a plastic window is not so difficult as it is responsible. If in doubt about your skills, it is better to call a specialist.

Procedure for replacing the glass gasket:

  • removing the glazing bead;
  • dismantling the lining and glass unit;
  • dismantling a worn seal;
  • installing a new seal through the groove. It is better to cut the tape, which is 3-5 cm longer than the required length, in advance. The new seal is put in place, while acting as carefully as possible and not pulling the material. Surplus is carefully cut off. If desired and for guarantee, the seal can be additionally fixed with an adhesive;
  • installation of a glass unit, linings and glazing beads. Glazing beads are a fragile part, so they must be removed and installed with extreme care so as not to break. Otherwise, you will have to buy new ones.

The seal, which is located along the contour of the sash, may also need to be replaced. In this case, it is better to remove the sash. First, the decorative overlays are dismantled from the hinges, and then using a mounting handle or a screwdriver, the pin is pulled out of the hinge. It remains to carefully remove the sash, and only then it is very easy to remove the old seal from it. It is better to start installing a new seal from the top of the sash, gently pressing it, but not stretching it. It is better to secure the beginning and end of the sealing tape with glue. All! It remains only to hang the sash back: the pin can be installed with bare hands, and then the decorative strip can be replaced. The video shows and describes everything very well.

No. 5. Window sill insulation

Installation of a plastic window is often associated with decent destruction, they are especially significant in the area between the wall and the window sill. Some installers throw cement and debris into the cracks. No comment here. It is better, of course, when the space under the windowsill is filled with polyurethane foam, but this option is not ideal either. The foam can shrink or even dry out over time, forming decent cracks through which cold air enters the house.

To insulate a plastic window, you will have to get rid of the old foam and fill in a new one. Keep in mind that it tends to expand as it solidifies. The surplus is cut off after complete solidification; some builders recommend additionally filling small cracks with silicone sealant. This is followed by plastering and decorative coating.

If possible, the window sill area can be additionally insulated from the outside. For this, polyurethane foam is also used, but sometimes foam is also used. From above, everything is plastered on a grid and finished.

No. 6. Insulation of slopes

Today, often during the installation of plastic windows, slopes are additionally installed, smooth, beautiful, made of dense plastic. It often happens that there is a large crack between the decorative strip and the wall, which perfectly conducts cold and wind into the apartment, therefore, to improve the thermal insulation of plastic windows, it is recommended to insulate the slopes from the inside or outside.

The procedure is as follows:

  • dismantling unnecessary parts of polyurethane foam;
  • if the surface is very uneven, you can plaster it;
  • treatment of the slope with a primer, you can use antibacterial compounds to prevent the development of mold;
  • a fragment corresponding to the slope is cut out of the foam. In order for it to better adhere to the surface, it can be slightly scratched on the back side. It remains to apply assembly glue and press firmly against the surface of the slope, to guarantee you can install several dowels;
  • it remains to mount the corner, putty the surface and fix the platband.

No. 7. What else can be done to insulate a plastic window?

The above methods will allow you to reliably insulate plastic windows and get rid of all the cracks, but there is an opportunity to make the structure even warmer – it will not only not let cold into the apartment, but will also prevent warm air from escaping from the apartment. This is not magic, but reality, which is achieved through the use of:

  • heat-saving film;
  • electric heating of windows;
  • woolen blinds and curtains.

Heat-saving film is a thin transparent material that does not change the optical properties of glass, but reflects heat energy back into the apartment. The effect is achieved due to the presence of a thin metal layer. Of course, when it comes to plastic windows, it is better to use a special heat-saving glass unit – its efficiency is several times higher than any film, but if a regular glass unit is installed in the existing windows, then additional insulation will not be superfluous.

You can easily handle the installation of the film yourself:

  • glass surfaces and frames are thoroughly cleaned;
  • double-sided tape is glued around the perimeter of the box;
  • the necessary fragment is cut from the roll of film, it is better to cut with a margin;
  • the film is glued to the previously attached double-sided tape, its surface is blown with warm air from a hair dryer. It is necessary to act slowly so that the result is neat, there are no distortions and bubbles. Correctly glued film is almost invisible.

It is already more difficult to equip electric glass heating, it is better to do this even at the stage of installing windows, but most window companies can install such a system already on an installed window. Heating is carried out by means of an electric heating coil mounted in the glass.

Well, and finally, the most banal, simple and universal ways to make the window a little warmer. These are thick curtains and wool blinds. The latter can be done by wrapping ordinary blinds with woolen fabric.

It is better to carry out work on insulating plastic windows on a warm, dry day, since it is no longer possible to work with many materials at temperatures below + 5 … + 100C, and you can let the cold into the apartment. In order to face the problem of warming a modern window as late as possible, it is worth taking the choice of a window manufacturer as seriously as possible, paying attention to the selection of optimal technical characteristics, focusing on the climate of the region. It is also important to choose a responsible installer and not forget about the need to properly maintain the window.

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Passionate about DIY for over 10 years and all the new tools, I give you through this blog all my advice, tips, tests in all areas: carpentry, electricity, masonry, gardening, home automation ...


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