Janet Thompson 
Have you ever dreamt of a well-lit house, all glazed, with a breathtaking view of the ocean or mountains?
You have certainly been enchanted by the idea of a large balcony or terrace window, which is a kind of frame for a beautiful picture, which would be your exquisite garden. Let’s think how this vision, straight from modern Californian or Mediterranean houses, will look like when confronted with our climate.
Along with the development of construction, there is a fashion for connecting living rooms with the garden by means of glass windows on the terrace or balcony. Large windows, from the floor to the ceiling, make the room brighter and optically larger, enhancing the impression of open space. In addition, the large windows add a touch of modernity and luxury to the interior. Many will say that only the rich can afford large windows, because of the cost, heat loss, and the fact that you need a lot of money to heat such a house. Let’s see if that’s true.
Window types and prices XXL
When it comes to the prices of large windows or so-called terrace doors, everything depends on the construction and materials. Among the modern windows available on the market, we can distinguish three basic types: tilt and slide (PSK), lift and slide (HST) and folding (FST).
It is also important what materials they are made of. They can be wooden, wood-aluminum, aluminum, PVC + aluminum, or PVC only. Prices also depend on the size of the windows, e.g., terraces can be 30-70 percent more expensive than ordinary windows.
PVC windows will be the cheapest. Let’s compare prices. You will pay twice as much for windows with insulated aluminum frames as for PVC versions and up to three times as much for wooden ones.
As far as the construction is concerned, the cheapest are tilt and folding windows, tilt and slide windows are in the middle price zone, and the most expensive are lift and slide models. The price is also influenced by the glazing surface and glass thickness — the bigger the glass, the more expensive the window. In addition, the cost of installation, which usually ranges from 3 to 15 USD per meter of window circumference, but when installing large windows sometimes you have to use heavier equipment and then the cost doubles.
It should also be noted that it is worth buying roller blinds, blinds or awnings for such windows – they will be very useful in summer. If you are afraid of theft, you should equip yourself with anti-burglary roller blinds.
Large windows and heat losses
Before buying windows, please pay attention to their parameters. The one we are interested in due to possible heat loss is the heat transfer coefficient (UW).
Currently, the standard is 1.3 UW, but one should rather choose a model with a ratio of 1.1 UW. Windows considered to be energy efficient have a coefficient from 0.8-0.9 UW downwards. Nowadays, it has become very fashionable to build so-called passive houses, which distinguishes very low energy demand and very high insulation standard. For such houses, one buys windows with a coefficient of 0.6-0.7 UW.
The heat transfer coefficient consists of the frame coefficient (Uf) and the glass coefficient (Ug). The principle is that glass generally has a better heat transfer coefficient than a frame, so the larger the window, the better the heat transfer coefficient. In addition, the installation of glass with a low-emission coating (reflecting the heat radiation from inside the building) will further reduce the heat transfer coefficient.
To sum up: in order to reduce heat loss in autumn and winter and the cost of heating a house, it is necessary to invest in good equipment. It is also very important to install it because if the terrace windows are installed incorrectly, even the most energy-saving materials will not compensate for the loss of heat.
Large windows in summer
Apart from cold winters there are also very hot summers, and even if the loss of heat is stopped by using the best materials, there will be the issue of heating the interior of the house during the heat.
Usually, glazing with better thermal insulation lets less sunlight in. That’s the best option for summer. High solar transmittance factor (g) is a plus in winter because the room warms up, but in summer it will be too hot. Installing an air conditioning system is an additional cost and, in addition, a loss of energy. In such a situation, it is worth to think about additional accessories such as roller blinds, blinds, awnings, or hoods reducing radiation.
Advantages of large windows
Apart from the price of the window itself with the installation, it is worth considering the advantages of such an investment. Large terrace windows do not only bring more light to the room but also a beautiful view. In the case of a passive house, large windows located from the south can be a valuable source of energy, while remembering to install an external blind for the summer period.
Finally, a house with large terrace windows gains in value not only due to the increase in the market price but also due to the aesthetics of the building. Houses with large, modern windows are more likely to be bought, so when you decide on such a solution, you should think that it will be a great capital investment for your children and family.