ᐅ Energy Saving Regulation Certificate vs. Energy Saving Regulation Certificate + KfW 70 Certificate
Created on: 1 Jul 2015 12:41
J
jx7
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
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
S
Sebastian798 Jul 2015 13:33I find these figures quite interesting because they show that significantly more insulation doesn’t really make much difference...
We also have sand-lime brick walls with 14cm (5.5 inches) of mineral wool insulation and no insulation under the slab-on-grade foundation. Everything else is identical, with just under 200 m² (2150 sq ft) of living space including the basement (240 m² (2580 sq ft) total).
Annual primary energy demand
Q_p = 38.04 kWh/(m²·year)
Heat transmission loss
H'_t = 0.305 W/(m²·K)
It’s good to have a basis for comparison.
We also have sand-lime brick walls with 14cm (5.5 inches) of mineral wool insulation and no insulation under the slab-on-grade foundation. Everything else is identical, with just under 200 m² (2150 sq ft) of living space including the basement (240 m² (2580 sq ft) total).
Annual primary energy demand
Q_p = 38.04 kWh/(m²·year)
Heat transmission loss
H'_t = 0.305 W/(m²·K)
It’s good to have a basis for comparison.
The wall structure was specified by our construction company. I’m not sure if the windows and the front door are comparable between your place and mine. Apart from the description "triple glazing" for the windows, I have no further details. But in both your case and mine, the values are quite solid.
S
Sebastian798 Jul 2015 14:02The transmission loss is considered too high by some insulation enthusiasts. Our wall construction is just slightly below the energy saving regulations, but it’s sufficient for me, and I agree with you that it is perfectly adequate.
Have you already calculated the heating load?
The total windows have a U-value of 0.9, and the front door was calculated with about 1.1, but we will be getting a better one.
Have you already calculated the heating load?
The total windows have a U-value of 0.9, and the front door was calculated with about 1.1, but we will be getting a better one.
S
Sebastian798 Jul 2015 15:47No, it definitely needs to be properly calculated – I also specified the temperatures of the rooms and hallways instead of using the standard DIN values (which are much too low).
We have 8.1 kW – a calculation is highly recommended, especially when using a heat pump.
We have 8.1 kW – a calculation is highly recommended, especially when using a heat pump.
We are getting a modulating heat pump, which doesn’t just operate at a fixed kW output but can be smoothly regulated. This means that for half the heating demand in autumn or spring, it doesn’t cycle on and off like an 8 kW pump running at 4 kW, but instead modulates down to 4 kW. Does this actually make a difference? No idea. Our only guarantee is that the calculated seasonal performance factor will be above 4.5, so we qualify for the BAFA subsidy.
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