ᐅ KfW 70 | Requirements for Basement Windows?

Hello!

We own a semi-detached house that is currently under construction. We want to meet the KfW 70 standards.

According to our architect, single-glazed windows in the basement are standard, so we as the builders would have to cover the extra costs for double- or even triple-glazed windows ourselves.

Now I would like to know what the requirements are for the basement windows. Do they not have to be double- or triple-glazed to meet KfW 70?

Best regards

Architect???? I’m reading: "extra übernimmt".... Or are you building with a general contractor or developer?
Was the house’s energy performance not calculated in advance and the windows specified accordingly?
All of that is settled before construction starts (specifications and costs for energy efficiency programs)....

slavik schrieb:


According to our architect, single-glazed windows in the basement are standard, so double or even triple glazing would have to be covered by us as additional costs.

Now we want to know, or rather I want to know, what the requirements for basement windows actually are. Don’t (!) they have to be multi-glazed to meet KFW 70 standards?

Best regards

Single-glazed windows are standard? Even at a hardware store, you would have trouble finding such windows nowadays, as they are considered rare.

As for KfW 70, this should be evident from your energy performance certificate. The main parameters should have been calculated there.

Hello,

slavik schrieb:

Now I would like to know what the requirements are for basement windows? Do they have to be double-glazed to meet KFW 70 standards?

Your architect probably referred to "basement light wells," right?

These are nowadays usually prefabricated elements with double glazing and are perfectly sufficient for a utility basement. If you plan to create living spaces in the basement, then—besides appropriate insulation (also for an individual room used as a residential unit within an otherwise utility basement)—regular windows must be installed; emergency escape routes must also be considered.

Whether you have to cover the costs for the double-glazed basement light wells depends on the specifications in the offer from your trusted supplier.

Regards, Bauexperte

@slavik, is there any update?

We have masonry light wells with triple-glazed windows installed, just like everywhere else in the house. Since the basement rear wall cannot be insulated from the outside, double-glazed windows were not an option. It was an expensive choice; the windows are relatively small, and paying nearly 500 euros for a 70cm x 90cm (28in x 35in) window was quite painful. In hindsight, it probably could have been left open...