Energy Saving Ordinance Proof vs. Energy Saving Ordinance Proof + KfW-70 Proof

Hello everyone!

If an energy consultant carries out an energy saving ordinance calculation for a new building, is the creation of the KFW-70 certification still relevant additional work that may be associated with extra costs?

Does anyone have cost estimates for energy consultant fees for a single-family house with 146 sqm living space plus 73 sqm basement, once only energy saving ordinance certification, once energy saving ordinance certification plus KfW-70 certification?

The house has the following characteristics:
- 17.5 cm lime sand brick, 20 cm insulation
- Geothermal (brine heat pump with deep drilling with a calculated annual performance factor of at least 4.5)
- Central controlled residential ventilation with heat recovery
- South orientation
So it should definitely be KfW-70.

Best regards

jx7

20 cm insulation? Why so much? Have you calculated what that extra insulation really brings you? We have the same combination and 14 cm insulation – and achieve KFW56...

Of course, there are more values involved, but roughly speaking, you can easily reach KFW70 with that. I would always look at what the extra insulation costs you and what you would save per year.

We paid 500 euros plus tax for the energy saving ordinance and KFW calculation.

Thank you Lexmaul. Do you know how much of the 500 € plus VAT was for the Energy Saving Ordinance and how much was for KfW? Do you also have geothermal energy and controlled residential ventilation with heat recovery?

150 euros was for KfW - and yes, we have both.

We now had to pay an additional €500, but that included not only the creation of the KfW calculation before construction, but also the necessary construction supervision and work during the construction, whatever else needed to be done.

By the way, with our construction method (17.5 cm sand-lime brick, 20 cm insulation, 10 cm insulation under the floor slab, triple glazing, geothermal/deep drilling, controlled residential ventilation with heat recovery, 146 sqm living area plus basement), we ended up with the following values:

Annual primary energy demand
Q_p = 34.5 kWh/(m^2a) => 54 % of the reference house

Transmission heat loss
H'_t = 0.305 W/(m^2 K) => 79 % of the reference house

Required for KfW-70 are Q_p < 70 % of the reference house and H'_t < 85 % of the reference house, so this is met.

Required for KfW-55 are Q_p < 55 % of the reference house and H'_t < 70 % of the reference house, so this is not met.

For various reasons, it does not bother us that we do not have KfW-55:

1) Our bank Ing-Diba only mediates KfW-70 loans anyway.

2) KfW-55 requires higher energy consultant costs for the stricter verifications.

3) We have little incentive to reach KfW-55 through further cost-incurring construction measures because with geothermal energy we can generate heat very cheaply and the savings potential from additional insulation, better windows, etc., therefore does not seem high to us.