Useful to know

Aknakoda / Useful to know

Useful to know

The selection of different plastic windows is wide. The most important aspects in case of windows are the thermal performance, opening possibilities and colour. 

With the following we will try to be of assistance to you by giving simple recommendations for making the best choices and submitting a price enquiry in the ,,Submit a price enquiry’’ module. 

Thermal performance 

We make plastic windows with different thermal performance and therefore need to know for which building the windows are intended. The thermal performance of windows is measured with a U-value*. The lower the value, the greater the thermal performance of a window. If you need windows to be installed in a non-heated room or into rooms with low thermal demand, an excellent thermal performance of windows is not important. For that purpose we recommend our Standard window (70 mm profile and double glazing with selective glass* – Uw=1.4W/m2K). If you need windows for a properly insulated building, our recommendation is the SYNEGO profile system (80 mm profile and triple glazing with two selective glasses – Uw=0.88W/m2K). In case of a passive house we recommend the GENEO profile system (86 mm thick profile and triple glazing with two selective glasses – Uw=0.78W/m2K).

A few explanations:

1) U-value* shows how many W (watts) of thermal energy per hour transfers from a room through one square metre of window space. The Uw (window) values of windows have been indicated above. In order to comprehend the essence of the specified numbers in more detail, here are a few examples:

 a) U-value of an uninsulated large-panel building wall = 0.5 to 0.7 W/m2

 b) U-value of an insulated large-panel building wall = 0.3 to 0.5 W/m2

 c) U-value of buildings from modern materials = 0.2 W/m2

* the given numbers are average indicators, and different buildings have certainly somewhat different thermal performance indicators.

NB! As a rule the thermal performance of windows is lower than the thermal performance of walls of a building but the difference in the performance could be smaller if possible – you just need to choose the windows with the best indicators! 

SYNEGO profile system gives you the best price to quality ratio.

2) Selective glass* – bright glass with a thin layer of metal applied on the internal side of the glazing which reflects the indoor heat (thermos effect).

 Opening possibilities                                                                                                    

Windows can be made as non-opening and opening (opening inward as a rule). You need to make your choice according to the need. Certainly, non-opening windows are cheaper than opening windows but your choice should not be based on that alone. Window opening possibilities are as follows:

a) Turn position – the window opens from the side

b) Tilt position – the window only opens ca 10 cm above for ventilation

c) Turn and tilt position – the window can be opened completely and put in the ventilation position as well

When choosing windows, in addition to the need to ventilate, you should also account for the need to wash i.e even if you don’t need to open the window for other reasons, you still need to wash them.

Colour of windows

As a rule, a window is white from the inside and outside. However, the colour range of windows is extensive. As on the computer screen the colours seem somewhat different from the actual, our recommendation is to make the final decision on the colour by examining the samples with our sales representative. You may choose the colour in the price enquiry and change it later if necessary.                                                                                                                                                  

To conclude:

Now that the basic things concerning windows have been explained, you need to think about the works connected with the installation of windows. The whole process includes the following works:

1) Removal of old windows and installation of new ones.

2) Finishing of external window jambs – new corner flashings will be installed or something else depending on the specific nature of the object. It will be specified in more detail on site.

3) Installation of new internal window sills.

4) Finishing of internal window jambs (e.g plastic enclosures)

5) Utilization of old windows and other construction waste.

The works specified above can be ordered in aggregate or in parts.

Of course you will have other questions relating to the selection and replacement of windows (security glasses, special-shape windows, insect nets etc.), but these can already be discussed with our sales representatives in more detail or you can list your requests under the field ,,Additions, special requests” at the end of the price enquiry. 

The above should suffice to understand the offered products and services and to make your initial selection.

Now you can submit us a price enquiry after which we shall be in contact with you. 



Submit a price enquiry

When the window glasses are wet (condensation)

Probably everyone has experienced the occurrence of condensation on windows at some point. It may have occurred either on the internal or external window glass. This condensation does not separate from the window but the occurrence thereof on the glass has certain physical reasons. We will try to explain the problem as easily as possible and without complicated terms and propose the possible solutions.

Condensation on the internal glass (as a rule at the bottom of the window at the edge of the glass)


  • The thermal resistance of windows (glazing) is bad e.g double-glazed windows (UW 1.3W/m2K or higher)
  • The amount of humidity in the room is higher than allowed (55-60% or more) – the ventilation of the room is deficient or lacking altogether
  • The outside temperature is low (minus degrees, the lower the worse) and air humidity is high
  • The room temperature is lower than the normal temperature (+18 degrees or lower), e.g the heating period has not started yet
  • Normal (free) movement of air does not reach the window glass. The windows are covered with thick curtains or blinds (the room temperature may be +20 degrees and more but the temperature at the window behind the curtain is considerably lower and even ice may form).
  • Damages the interior finish of window soffits within time, mould may occur



  • Windows should not be covered with thick curtains or blinds. By doing so, the temperature between the window and curtain/blind is considerably lower and there is no movement of air and condensation occurs on the glass. A gap of at least 20 cm must be left between the curtain/blind and window sill so that the air could get between the curtain/blind and the window (the air moves and the temperature at the glass is thereby higher
  • If the humidity is higher than normal, a ventilation system must be built or the windows must be opened regularly to ventilate the room
  • The room temperature must be at least +20 degrees
  • To achieve the best result in case of windows with poor thermal resistance (UW 1.3W/m2K or higher) we recommend replacing the windows with new ones with sufficient thermal resistance.


Condensation on external glass (majority of the glass surface is covered with condensation and looking out the window is difficult)


  • The thermal resistance of windows is very good (UW is 1.1 W/m2K or lower) and thereby the external glass surface is cold
  • Relatively quick increase of temperature early in the morning at sunrise
  • High air humidity outside


  • There is no reasonable solution what a person could control him/herself. Your windows have sufficient thermal resistance (saving energy i.e the heat is ensured) and the potential occurrence of condensation due to the aforesaid reasons is inevitable. Condensation disappears from the external glass within a couple of hours after the temperature on the glass reaches the equal level with the air temperature and external air humidity reduces.


  • If the thermal resistance of windows is good, the heat from the room does not reach the external (outside) glass and the external glass is cold (which is good as we save the room heat). If there is high air humidity early in the morning and the outside temperature increases relatively quickly (sunrise), condensation occurs on the cold glass surface (temperature of the glass is lower than the air temperature). In case of windows with not so good thermal resistance, the room heat transfers outside through the glass and thereby keeps the external glass at higher temperature (thermal loss takes place) and there is no condensation on the external glass as a rule.

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We offer the finest PVC windows and doors in Estonia. We believe we can meet even the most demanding client's wishes and expectations. Send us a price inquiry, and we will find the best solution for you.
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