ᐅ Energy Saving Regulation Certificate vs. Energy Saving Regulation Certificate + KfW 70 Certificate

Hello everyone!

When an energy consultant performs an energy performance calculation for a new build, is preparing the KfW 70 certificate still considered additional work that justifies extra costs?

Does anyone have cost estimates for energy consultant fees for a single-family house with 146 m² (1572 ft²) of living space plus 73 m² (785 ft²) of basement, once for just the energy performance calculation and once for the energy performance calculation plus the KfW 70 certificate?

The house has the following features:
- 17.5 cm (7 inches) calcium silicate brick, 20 cm (8 inches) insulation
- Geothermal system (brine-water heat pump with deep drilling, with a calculated annual performance factor of at least 4.5)
- Central controlled residential ventilation with heat recovery
- South-facing orientation

It should definitely meet the KfW 70 standard.

Best regards

jx7

20 cm (8 inches) insulation? Why so much? Have you calculated what the additional insulation really gains you? We have the same setup with 14 cm (5.5 inches) insulation and achieve a KFW56 rating...

Of course, there are more factors involved, but roughly speaking, this setup would easily reach KFW70. I would always consider the extra cost of the additional insulation and what you would save annually.

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

Thanks, Lexmaul. Do you know how much of the 500 € plus VAT was for the energy saving regulation and how much was for the KfW program? Do you also have geothermal energy and controlled residential ventilation with heat recovery?

150 euros was for the KfW loan - and yes, we have both of them as well.

We had to pay an additional 500 € surcharge, but this included not only the preparation of the KfW calculation before construction, but also the necessary construction supervision and any work required during the building process.

Our construction method (17.5 cm (7 inches) calcium silicate brick, 20 cm (8 inches) insulation, 10 cm (4 inches) insulation under the floor slab, triple glazing, geothermal energy/deep borehole, controlled ventilation system with heat recovery, 146 m² (1570 ft²) living space plus basement) has resulted in the following values:

Annual primary energy demand
Q_p = 34.5 kWh/(m²·a) => 54% of the reference building

Heat transmission loss
H'_t = 0.305 W/(m²·K) => 79% of the reference building

For KfW-70 certification, Q_p must be less than 70% of the reference building and H'_t less than 85%, so these requirements are met.

For KfW-55 certification, Q_p must be less than 55% and H'_t less than 70% of the reference building, so these requirements are not met.

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

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

2) KfW-55 requires higher energy consultant fees due to stricter verification.

3) We have little incentive to invest in further costly building measures to reach KfW-55 because with geothermal energy, we can produce heat very economically, and the savings potential from additional insulation, better windows, etc., does not seem significant to us.