Quality windows - lower heating costs

How to choose the right window to save money on heating?

Questions for Mr. General Manager Albo

Demands for thermal insulation are increasing, and it is not only the external walls that are important for the envelope of a house. How are window manufacturers responding to the tightening conditions?

Manufacturers are trying to respond by reinforcing window frames and sashes, which themselves have better thermal parameters and can be fitted with triple glazing of greater thickness with better Ug parameters. For example, we offer the ALBO strong 3+ window profile in 92mm thickness with Uw=0.71 and the altrend passiv wood-aluminium window with Uw=0.65.

Is it still possible to find innovations in frame construction? Is it still possible to reduce the U or R factors at all?

I think it is certainly possible to reduce Uw in the future. However, at the moment we have standardized some window types to meet the standards for passive houses, yet they are no longer just a matter for the top ten thousand. Nowadays, window types with Uw below 0.5 have been developed, but their purchase price is still high.

In many cases, the discussion about windows is limited to a discussion of frame materials. In terms of suitability for energy-efficient houses, can any of the materials be discussed as the material of the future?

Yes, in this respect, wood-aluminium is clearly the material of the future; it perfectly meets all the requirements of today's customers - e.g. very good insulation properties, high durability thanks to the aluminium cladding on the exterior, beautiful natural wood on the interior, etc.

And what is the path of custom glazing - what are the trends in glazing?

A very interesting innovation is insulating glass with higher solar gains, the solar gain is referred to as g in insulating glass. In my opinion, the customer should always check not only the U parameter of the insulating glass (the lower the better, of course), but also the solar gain parameter g. Some manufacturers already list not only the U parameter but also the g parameter in their price offers. Just for comparison, for standard triple glazing in these windows the value of g=50% (i.e. 50% of the sun's radiation passes in). Unfortunately, we have also encountered triple glazing with Uw=0.4 on the market, but g was only 36% for these glasses! In this case, the customer is buying windows with amazingly low Ug glass, but in autumn, winter and spring he will have to heat much more even if the sun is shining, because the glass with g=0.36% really does not let much sunlight into the house. Nowadays, triple glazing with g=63% can be found on the market, which will allow the interior of the house to warm up nicely just from autumn to spring, so customers will save money on heating during these periods. For the summer period, these insulating triple glazing units must be supplemented with an integrated inter-glazed blind or an external blind or roller blind to prevent the interior from overheating. For the south and west sides of the house I would definitely recommend these windows with higher solar gains, because the return on investment in these windows is very quickly recovered due to the fact that the house is heated significantly more during the day by solar energy and therefore we do not have to heat as much. Interestingly, abroad it is common to see not only the Uw parameter but also the g parameter in the design of windows. In the Czech Republic, this value is somewhat forgotten and the glass parameter g is often not addressed at all.