How to choose the right window according to the price/performance ratio

Questions for Mr. Albo, Chief Executive Officer

Windows are often referred to as "black holes" in the construction of energy-efficient and passive houses, where heat escapes. Is this still true?

Yes, it is true that in low-energy and passive houses, the windows in the envelope of these houses have slightly worse parameters than the walls of the houses themselves, but I would certainly not call them a black hole. Today's modern windows already achieve really good insulation properties. We have to remember that windows have undergone a lot of innovation in the last 20 years. High-quality timber and aluminium windows nowadays have a heat transfer coefficient Uw of less than 0.75 W.m-2.k-1 , which I think is a very good value indeed.

What solution would you recommend for a case where the architect proposes large glazing but at the same time maximum thermal protection is required?

I would definitely recommend triple glazing, it can be produced in large formats and guarantees very good insulation properties. Triple glazing with a heat transfer coefficient of Ug=0.5 w-m-2.k-1 and a solar gain of g=63% is ideal. It is also very advisable to fit a shading system at the same time as these glasses, especially if the south and west sides of the house are involved.

What is the relationship between the thermal protection of the glazing and the frame? Is it possible - in layman's terms - to add to the frame (more chambers, insulation) at the expense of the glazing, for example if I am counting on using exterior blinds?

The answer to this question is simple. Whenever you buy a window, look at the window's parameter - the thermal transmittance Uw - which gives you a clear indication of the overall insulating capacity of the window as a whole, i.e. the frame and the glass. Of course, the lower the Uw, the better the window insulates. Don't forget to also ask about the solar gain of the windows, referred to as g, it should definitely not be less than 50%. Where we want to have a healthy living with plenty of sunlight, it is advisable to install so-called super clear triple glazing with a solar gain of g=63% on the south and west sides of the house. For these windows with higher solar gains, shading is always necessary to prevent the house from overheating in summer.

Is there any way to choose the right window according to the "price/performance" ratio? Could you advise our readers what to look out for most?

Every customer has slightly different ideas about what is important to them in windows. However, I think that nowadays the most important aspects are - durability, maintenance-free, natural materials and high energy savings are also ideal. If you add up all these aspects, you will find that the ideal window for you is a wood-aluminium window that meets all these requirements. We have more than 5 model series of aluminium windows in our offer.