Current requirements regarding windows are extremely demanding. They have to be energy-efficient, beautiful and they have to ensure high safety level.
Round, colorful, wooden, plastic, with or without grilles. When we decide to buy a new window, the choice is never easy. We need to remember that the window has to be pretty and, above all, it should protect our house against external factors. Therefore, we need to know which parameters should be taken into account when choosing a window and what to ask the seller before we make the final decision.
There are numerous window parameters. The profile is important, since it determines the window stability and correct operation, as well as the seal system. Thermal and acoustic insulation is also crucial because it shows if the window will protect the house against heat loss and noise. What matters is also resistance to wind load, water tightness and air permeability – these parameters are decisive in keeping the house dry and warm even during heavy downpour and strong gale.
Profile made of prime material- quality
The basic parameter that characterizes the window profile is class. A-class is the highest possible. It means that the external visible window walls are at least 2.8 mm thick and the internal chambers are at least 5 mm wide. It guarantees high stability and durability, as well as better protection against noise and thermal changes. If we opt for high-class window profiles, we will avoid problems arising from profile deformation or window buckling. It is important to make sure the window is made of 100% prime material, since it significantly improves its quality! We need to ask about certificates and confirmations because they determine the usage comfort in the future.
Seal – thermal insulation
According to the calculations of the Polish National Energy Conservation Agency, up to 35% of heat loss occurs through windows. How can we avoid that? Buying energy efficient windows. Thermal insulation of the window is defined by U the heat transmittance coefficient. The lower it is, the less heat loss occurs. Currently in Polish market the requirement is U coefficient lower than 1,1 W/(m2K). However, there are windows that are head and shoulder above this parameter!
One example is Iglo Energy PVC window from Drutex S.A –the biggest European producer of windows and doors, where heat transmittance coefficient is only at Uw=0,6 W/(m2K)* level, which is 100% better result than the market requirement! Thanks to such low parameters the window may be applied also in energy efficient and passive buildings.
High-quality glass - perfect silence
It is a good solution to buy windows with glass characterized by enhanced acoustic insulation. Rw coefficient given in decibels determines how the window will insulate the room from external noise. It is worth considering if our house is near busy streets, railway tracks or an airport. We need to choose then windows with sound-proof glass with Rw at 36, 39, 40 or even 50 dB level. However, if external noise does not exceed 60 dBA, it is enough to fit windows of Rw = 30 dB. Glass also constitutes an investment in energy efficiency. DRUTEX is fully aware of that, therefore it is the first company in Poland to have applied, in cooperation with Saint-Gobain, new generation glass packages which guarantee high thermal insulation.
Structure strength – Resistance to wind and rain
The measure of window resistance to wind load is the structure deflection to wind. The feature is defined by A1 to C5 classes, where the higher the class, the more resistant the window is to wind load. This factor is important for owners of flats in high-rise buildings or in the mountains.
Water tightness is one of the parameters that are most difficult to achieve by producers. It is said that this parameter determines the actual quality of the woodwork. Water tightness is expressed in 1A to 9A scale. The lowest 1A scale means that the window will leak even in no wind conditions. The almost highest 9A scale guarantees tightness even in a storm with 600 Pa (that is 112 km/h) pressure. – In this difficult category our Iglo Energy window achieved 1200 Pa result, which confirms the great properties regarding the window tightness in all weather conditions, including heavy downpour – says Bogdan Gierszewski, production director at DRUTEX S.A. – We worked on this product for months, and our R&D department analyzed each millimeter of the new structure.
In conclusion – before you buy the window, remember to ask the seller about tests, certificates and technical attestations that confirm the parameters declared by the producer. It is important because the window will serve us for years to come.
*for a window of 1230mmx1480mm according to the CSI in the Czech Republic