Reliability of an energy calculation for KFW55, too high?

Hello everyone,

for our new building with 2 full floors and a cellar, we have now received a calculation for the entire Kfw application, but it seems to me that the values are calculated quite high, or even incorrectly.

A few data about the house:

[*]Specifications from the architect's plan living area ground floor 75sqm & upper floor 70sqm (air space hence the difference)
[*]Clear height ground floor 2.7m & upper floor 2.5m
[*]Cellar not heated, air-water heat pump in the cellar.
[*]Attic not developed
[*]Air-water heat pump with ventilation system with heat recovery
[*]The expert appraiser comes to 277sqm usable area, that seems very high to me! He then continues to calculate based on that for electricity consumption and comes to a final energy demand of 4860kW/a

Is that the electricity consumption I will need or am I misunderstanding something? That seems very high to me!

Thank you very much in advance.

4860 kW/a !? Do you mean 4860 kWh per year heating demand or primary energy demand or final energy demand? Heating demand would be very low, primary energy very high.. Final energy at 22 cents per kWh would mean 90 € per month - for hot water and heating including the basement not so unlikely. Could you possibly anonymize the report and upload it? As it is, there is a lot of guessing involved.

Hello, this topic is very complex and a layperson can hardly explain it to you. But, purely theoretically and assuming the given factors, you need 4,900kWh heating energy or more or less. It does not say where you get this heating energy from and how it is generated. However, if you calculate with a COP of 3, you should get by with 1,600kWh of electricity. Or 1,500 or 1,800 or whatever. Initially, it will be even higher anyway. This consideration is very theoretical and does not reflect reality. But I don't find it quite unrealistic for the [house size].

As already mentioned, I mean the final energy demand of 4860 kW/a.

The basement is not heated and not inhabited.

The calculated annual primary energy demand Q according to the Energy Saving Ordinance for the new building is 31.6 kWh/sqm.

Built-up area is 11x9 m!

Solid construction.

All data see [Anhang]. I do not understand the calculation of the usable area, the basement is not heated!!!

The heating must be inside the insulated envelope, is it?

Is the basement ceiling insulated or the basement floor? What about the basement walls?

At all: What belongs to the thermal envelope?

The heating is in the basement, which is insulated according to Kfw55. Is the basement counted as living space in the consumption calculations even though there are no radiators or underfloor heating there?? The usable area just seems very large to me!