Window difference Uw 0.67 to 0.74

Hello everyone,

slowly but surely I have gathered all the necessary offers. At the moment, I am a bit stuck with the windows.

I have a total of 3 offers from different manufacturers. Prices and appearance do not differ much in 2 offers (about 3000 euros). The Uw value is also quite similar, 0.69 vs. 0.67.

However, the 3rd offer is much cheaper, about 8000 euros. But the Uw value here is only 0.74.

Otherwise, the windows are the same (plastic/aluminum).

My question is whether you can notice the difference between 0.74 and 0.67? Or is it so minimal that it will never pay off?

Just based on feeling, I would tend to go for the best Uw value... but the question is whether it pays off or if it is just a design decision.

Thank you very much.

P.S.: The windows are not relevant for a KFW value. This is met by all windows.

My question is whether you can notice the difference from 0.74 to 0.67?

No, you don't notice it. Neither in feeling (perceived cold when sitting by the window) nor in a really measurable saving in heating energy. I would take the cheaper offer immediately. No ifs or buts. Unless you are building so high-quality anyway that the €8,000 doesn't matter.

Yes, the U-value is not decisive. I would take a look at/feel the offered plastic profiles. There are some that really seem high quality and others that, in turn, remind one of social housing.

The feel of the plastic profiles is clearly also a matter. The two "better" manufacturers are Josko and Internorm, and the "more affordable" one is a smaller manufacturer from a trade fair... here the windows do not appear as robust and elegant as those from the two Austrians.

What is the structure of the discs, please also pay attention to the sound insulation ....

There are (almost) no small window manufacturers anymore; behind them are usually (possibly white label) producers operating under Schüco or Kömmerling licenses. I strongly recommend never to look at windows individually, and to source product and installation from a single provider. The references should therefore be convincing in both aspects. Price differences (8000 euros is the difference, based on which reference value?) are often difficult for laypeople to understand. You can send me the offers informally—I don’t think private messages are working well at the moment, but I have the same username at GMX (de) email-wise.