Performance calculation for heating

Does anyone know exactly how this works? According to the building application, we have a total nominal output of 10kW, but since our architect is the embodiment of incompetence and I have only planned a 6kW heating system so far, I would like to know what your experiences are with the outputs for heating in a detached small (120sqm) single-family house? We want to heat with geothermal energy and build at least to Kfw 70. Here the output is now decisive for the drilling depth. In the graphic it also says that since 2002, one calculates 5kW for 100sqm.

Well, you can't really answer that in a general way because there are simply far too many factors involved.

Starting with the wall and roof insulation, the amount of window areas and their insulation, the building structure and the ratio of exterior surface to room volume, all the way to the comfort factor.

For orientation: we have a totally crappy building structure with endlessly many exterior surfaces, but very good insulation and well-insulated windows, and we manage with a 125 sqm living area + utility room without a basement using an 8 kW heating system, including hot water preparation.

But without the calculation according to the [Energieeinsparverordnung], you won't get far; even better would be a heating load calculation taking your own temperature preferences into account.

Rather 4 to 6 kW - not 10. Go to Uwert, take your energy saving ordinance and tick it there.

According to which KfW standard did you build? When is the energy saving regulation calculated? We just submitted the building application.

How large is the heating load for a house with 150 m2 of heated area and thermal insulation according to the Energy Saving Ordinance 2009? From Table 31, the specific heating load for insulation according to the Energy Saving Ordinance 2009 is 30 W/m2. Thus, the heating load is calculated as: Q · 150 sqm x 30 W/sqm = 4500 W = 4.5 kW

If you build to Kfw70 standard, it is clear that you insulate well and the windows have a U-value of about 0.7. But somehow I have the feeling that heating systems are being planned too large, so I find it interesting how big your heating systems are for which sqm and which KFW standard?

A heating load calculation according to DIN costs about 200 euros – why wouldn’t you invest in something like that?

Calculating it yourself as a layperson is also bad advice – you, BeHaElJa, should know that by now

I hired someone who then designed the underfloor heating at 45°C supply temperature and ended up with 12 kW heating load in the individual room calculation.... that is the sad part. We have 190 sqm and a 5.3 kW brine-water heat pump. Generalizations like 30 W/sqm I consider questionable. As an approximation, fine...