kfw40 single-family house location dependency?

Hello everyone,

I have noticed that the orientation of the house plays a role in whether a house is considered a 40s standard or not.

From my point of view, that makes sense, since the energy consumption in a house in a sheltered location and mild temperatures is different from the identical house unprotected and in a colder environment.

Is that actually taken into account in the calculation? Or what exactly is meant by orientation?

I would be very happy if you could enlighten me, as unfortunately I cannot find anything about this on the internet. (Which is an indication that it is not the case :))

Best regards

A house consists of walls and doors and windows. If the large windows and patio doors from the living area face south, there are more thermal gains for the house. Therefore, the orientation is important for a KfW classification and calculation.

A house consists of walls and doors and windows.

… and of heating, ventilation, and insulation.

If there are mild, sunny winters, the house needs less energy; when it gets cold, more. The same applies to mild climates as well as harsh locations. We leave the calculations to the experts. However, they only calculate the house.

In fact, window sizes in the orientations play a role in passive houses alongside the U-values because other energy sources are taken into account. That is why a Kfw40 is not the same as a passive house, but a passive house is a Kfw40.

But basically, the rule is: whoever builds smartly, whether a 70er or a 40er, uses fewer and smaller windows facing north, and larger ones facing south.

Whoever builds smartly, whether a 70s or a 40s, uses fewer and smaller windows facing north, and larger ones facing south.

... and whoever builds nicely or can afford 3€ more heating costs per month installs reasonable window sizes everywhere regardless, to create beautiful and bright rooms ;-)

reasonable

… Of course, one can rack their brains about the meaning of "reasonable", especially when smaller auxiliary rooms such as storage room, WC, or freezer are planned to the north ;)

For large window fronts facing south, one should not be bothered if it is 25 degrees during lunch breaks on beautiful winter days. In terms of heating costs, solar gains and the worse U-value of windows compared to walls are likely to more or less balance each other out.