Summary of important characteristics when choosing windows


Possible classes and values in
descriptions of windows, to individual choice

The values most frequently chosen by the

Resistance to wind load

class A1-C6 B-3/B-4
Water resistance class 1A-9A 9A
Air permeability class 1-4


Acoustic properties specified value Rw [dB] in a noisy area Rw not less than 40-45 dB
Heat transfer specified value Uw

Uw no greater than 1.3 W / (m2 · K), the energy-efficient buildings 0.8-1 W / (m2 · K)

operating forces class 1-2 2
Mechanical strength class 1-4 4
Resistance to multiple
opening and closing
5000-20 000 cycles 10 000 cycles
Resistance to burglary class WK-1-WK-6 WK-2
light transmission percentage > 70%
Solar energy transmittance  percentage g factor energy efficient buildings over 45%
 *Its not worth to specify all the properties at the maximum level, such a window would be very expensive. Its wiser to invest in those in which we most care


Important parameters of windows - Continued

  • The heat transfer coefficient Uw - it indicates how much heat escapes through the window. Usually it has a value of 1,3-0,7. The lower it is, the better. When you purchase it is worth, however to make sure that the vendor asked about Uw does not give us the value calculated for the glass. It is always lower, but has not much in common with the insulation of the windows. In the whole window it is always higher than glass. The thermal insulation of windows informs Ug factor, and the insulation of the window frame - Uf.
  • Sound reduction index Rw - is given in decibels and tells you how well a window suppresses noise. The higher the value, the better. In this case also you need to distinguish between Rw for the window of Rw for the whole window. Because they have the same name it is worth to make sure twice that we are talking about the ratio for the window
  • Infiltration rate - the window is tighter, the better the protection against noise and transmits less heat. Glazed windows are installed so frequently in order to save on heating, but not paying attention entirely to the fact that they may interfere with proper ventilation of rooms. Tight windows, that is about the infiltration coefficient of less than 0.3, can be used only if the house will be equipped with mechanical ventilation supply and exhaust. In homes with traditionally used air pressure and unsealed window to be used for infiltration ratio of from 0.5 to 1.0.
  • Tightness class - 1A to 9A. The higher it is, the window is tighter. Window class 1A retain the tightness from rainwater for 15 min at a pressure of 0 Pa. Windows 9A will be sealed by the same time at a pressure of 600 Pa.
  • Class of wind resistance - from A1 to C6. It specifies at which  perpendicular wind pressure will be the maximum deformation of the window frame. The least rigid are the windows of the class A1, and most - C6. Aluminum joinery due to its stiffness is often C5 class.




Only from a good manufacturer

In the case of windows not only declared  properties are important, by where they were produced. Better to avoid the windows of unknown brands, the production of which may be base on methods bordering on cottage industry. Good companies provide reliable information about production models, have a credible and transparent certification warranty.


Features windows, evidence of their quality

  • The quality and number of gasskets - the windows are mounted two types of gaskets - glazing and resistance. They both do not allow the water to enter the interior of the window profile and led hardwere to rust. Seals resistance are further firewall for wind, dust and noise. There are always two gaskets - one from the outside, the other of the inner side of the window. Flexibility and resistance to changing weather conditions provides the material from which they are made or EPDM or TPS. Always make sure all the seals was not less than 4.
  • Type of glass - windows, both normal and balcony or roof uses insulated glazing. Search for those with the lowest Ug, it will best protect against heat leakage. Remember that the glass can also be reinforced thermally and by bonding foil (burglary). Consider whether you need such solutions because they increase the purchase price.
  • Functionality and quality fittings - fittings are responsible for it, as how You open and close the window. They are raised using the handle. Her turn makes the hardware unlock the wing and you can open, move to the side or tilted from the vertical. Good quality fittings ensure comfortable operation of the window. It is worth to pay attention to it, in which the company has been equipped with the fitting window. Avoid unknown brands.
  • The number of chambers and the thickness of the profile - it affects among other things, thermal insulation. The more chambers, the heat transfer coefficient is lower. Standard 70mm.
  • Profile width - profiles also differ in width. This is very important especially in the windows of larger dimensions and thick glass. Using Profile with appropriately selected rigidity will ensure the good work of the wings and increase the strength of the frame.


Basic information

Door and window joinery is one of the most expensive components of finishing the building. The choice of the windows is best well to examine before making a decision. Although the technology used by us has a huge impact on the properties of the windows, for you it should not mean much. To make the right choice it is important to get a certificate for whole window stating his actual performance and ensure that You pay for a product You really need.


When buying a window, we often engage in discussion about the details of their design, the advantages of their components and perfect attention to detail. In this way, we get caught in marketing trap - we do not choose the product on which we depend, but praised by the reseller. Meanwhile, a good choice is to buy such a window that fully meets our individual needs and is appropriate certificates. Warm window,  not only worm glazing. Safe, but not one that has a few anti - burglar caches. The windows, which in practice will be tight and easy to use, and not one that theoretically has a chance to be such, because it says the vendor. Without specialized survey product is not complete. The window consists of many small and large components and it goes a long road from the factory to be fixed in the wall. Its test certificates gives investors a guarantee of buying a product with the declared parameters. Then the technology does not matter, what matters is only the end result, that is why our products are equipped with all the necessary certificates and declarations of properties, so you know that you bought this exact product that you wanted.


What you get:

Energy-efficiency certificate:                                  Declaration of properties:                    Technical approval:

























Important parameters windows

By specified in the regulations and standards properties that must meet the joinery we can prepare for you a set of parameters that correspond to the data window, allowing you to choose the most suitable offer in not only price but also in terms of technical characteristics. It is important to include the most matter information for us. First, you need to specify the size of the window, choose its partition and functions of the hardware, for example the double window with a fixed bar with dimensions of 147 x 147 cm. These basics are usually defined in the project and do not make trouble. The more difficult is the further part when You to specify expectations for the characteristics of windows






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