Hello everyone,
Even though the topic of the "right" building services technology and its various advantages has already been discussed extensively, I still cannot answer the general question of whether a KfW 40 plus house is truly advantageous for me.
In many parts of the forum, it is mentioned that, purely for economic reasons, the standard according to the Energy Saving Ordinance (EnEV) is recommended and that the additional costs for a KfW house generally do not pay off. I find this hard to understand.
We are currently planning the construction of a new single-family house built with solid construction, without a basement, with approximately 200 m² (2,150 sq ft) of living space and underfloor heating. Without going too much into detail (although general and undetailed comparisons are always difficult), I would like to present the following simplified calculation:
Additional costs for KfW 40 plus compared to the Energy Saving Ordinance standard:
Ground source heat pump (deep drilling): €12,000 (€20,000 instead of a gas boiler with solar system for €8,000)
Ventilation system with heat recovery: €12,000
Photovoltaic system with storage: €15,000
Total additional costs: €39,000
Subsidies:
Repayment waiver through KfW 40 plus: €15,000
BAFA subsidy for geothermal energy: €4,500
Remaining additional costs: €19,500
Is it really the case that these additional costs of €19,500 do not pay off over a reasonable period? (There are further costs for KfW 40 plus, for example for construction supervision; however, these are largely also subsidized, e.g. through the KfW 431 program).
Furthermore, a low-interest loan (currently 0.9%) of up to €100,000 can be obtained from KfW, and other banks do not treat KfW loans as regular loans, which additionally improves one’s creditworthiness.
Would you still say that, based on these figures, a KfW 40 plus house is not economically viable?
Thank you very much for your insights!
Even though the topic of the "right" building services technology and its various advantages has already been discussed extensively, I still cannot answer the general question of whether a KfW 40 plus house is truly advantageous for me.
In many parts of the forum, it is mentioned that, purely for economic reasons, the standard according to the Energy Saving Ordinance (EnEV) is recommended and that the additional costs for a KfW house generally do not pay off. I find this hard to understand.
We are currently planning the construction of a new single-family house built with solid construction, without a basement, with approximately 200 m² (2,150 sq ft) of living space and underfloor heating. Without going too much into detail (although general and undetailed comparisons are always difficult), I would like to present the following simplified calculation:
Additional costs for KfW 40 plus compared to the Energy Saving Ordinance standard:
Ground source heat pump (deep drilling): €12,000 (€20,000 instead of a gas boiler with solar system for €8,000)
Ventilation system with heat recovery: €12,000
Photovoltaic system with storage: €15,000
Total additional costs: €39,000
Subsidies:
Repayment waiver through KfW 40 plus: €15,000
BAFA subsidy for geothermal energy: €4,500
Remaining additional costs: €19,500
Is it really the case that these additional costs of €19,500 do not pay off over a reasonable period? (There are further costs for KfW 40 plus, for example for construction supervision; however, these are largely also subsidized, e.g. through the KfW 431 program).
Furthermore, a low-interest loan (currently 0.9%) of up to €100,000 can be obtained from KfW, and other banks do not treat KfW loans as regular loans, which additionally improves one’s creditworthiness.
Would you still say that, based on these figures, a KfW 40 plus house is not economically viable?
Thank you very much for your insights!
R
robin19884 Apr 2019 08:19RotorMotor schrieb:
I think you have overlooked some important points here, such as the increased planning effort and the building envelope with insulation, windows, etc. For a house this large (200m² (2,150 sq ft)), I would estimate an additional cost of at least €20,000. Thank you for your assessment. In our specific case, however, the planning effort should be relatively low. According to the first calculation, the insulation only needs to be increased by about 15% (for example, by insulating beneath the concrete slab). The windows are already up to the required standard (we have good contact with a window manufacturer).
It still seems likely, though, that the payback period will be quite long.
Away from the economic topic:
A Tesla isn’t economical either, yet they sell like hotcakes.
With a KfW40+ house, or even a plus-energy house, you are part of the solution, not part of the problem.
A new build that only meets the energy regulations is basically a newly built old house.
And back to the economic aspect: Thanks to photovoltaic solar panels, my heating and hot water costs yesterday for 300m² (3,230 sq ft) of living space at 22°C (72°F) and three people taking showers were: 3 cents.
A Tesla isn’t economical either, yet they sell like hotcakes.
With a KfW40+ house, or even a plus-energy house, you are part of the solution, not part of the problem.
A new build that only meets the energy regulations is basically a newly built old house.
And back to the economic aspect: Thanks to photovoltaic solar panels, my heating and hot water costs yesterday for 300m² (3,230 sq ft) of living space at 22°C (72°F) and three people taking showers were: 3 cents.
G
Grantlhaua4 Apr 2019 08:38We basically chose everything without paying much attention to the energy saving regulations and ended up with something better than KFW55. Going any lower would have caused significant additional costs for us, as you’ve already broken down nicely. Even with KFW, it never would have paid off within a reasonable timeframe. KFW was never really an option for us anyway, since the bank’s interest rates last year were much higher than KFW’s, and unfortunately, no special repayments are allowed with KFW anymore. (Over the loan term with KFW, we would have more
A photovoltaic system with a battery storage for 15,000 would also be quite challenging. Install a photovoltaic system on your roof for self-consumption and feeding electricity back into the grid (the power grid is still the best storage option anyway) and wait 10 years until decentralized storage might possibly become profitable.
Do you have a stratified buffer tank or what kind of configuration do you use?
A photovoltaic system with a battery storage for 15,000 would also be quite challenging. Install a photovoltaic system on your roof for self-consumption and feeding electricity back into the grid (the power grid is still the best storage option anyway) and wait 10 years until decentralized storage might possibly become profitable.
fragg schrieb:
And back to the economics: Because of the photovoltaic system, my heating and hot water costs yesterday for 300m² (3,229 sq ft) of living space at 22 degrees and 3 people showering were: 3 cents.
Do you have a stratified buffer tank or what kind of configuration do you use?
R
RotorMotor4 Apr 2019 08:40fragg schrieb:
Putting economics aside for a moment:
A Tesla isn’t cost-effective either, yet they sell like hotcakes. Unfortunately, that doesn’t mean it makes ecological or economic sense.
fragg schrieb:
With a KfW 40+ house, or even a positive energy house, you are part of the solution, not part of the problem. The same initially applies here.
Production involves higher energy consumption at first, including the transport of additional materials, and so on.
Are there detailed calculations showing whether this energy is recouped within 30 years?
The costs are always individual.
- What does "already included" mean? If you are planning a controlled residential ventilation system anyway, there are no additional costs that need to be considered.
- Photovoltaics pay off on their own; energy storage does not.
- Are the additional costs reasonable? Adding a bit more insulation isn’t expensive, but if you build with a general contractor who charges a premium for it, that can ruin the budget. Those who build with timber framing basically have the "KfW 40" wall as standard. Monolithic construction requires thicker walls and therefore loses space due to the bulky structure.
- An air-to-water heat pump is also an option; it doesn’t have to be a ground-source (geothermal) heat pump.
- If the overall concept is coherent, a ground-source heat pump can be cheaper since the drilling depth may be shorter.
- Are the KfW loan conditions attractive? The conditions were poor for the last two years but are now good again, sometimes even better than bank loans.
- Do you expect rising heating costs regardless of the energy source? If your consumption is low, these increases don’t matter much. The resale value can also benefit—starting in 2021, only passive houses qualify, and KfW 40+ standards are very close to that today. Check listings on real estate platforms for new builds from five years ago: look at their energy ratings and compare them to current KfW 55 standards—this influences buyers’ perceptions significantly.
- What does "already included" mean? If you are planning a controlled residential ventilation system anyway, there are no additional costs that need to be considered.
- Photovoltaics pay off on their own; energy storage does not.
- Are the additional costs reasonable? Adding a bit more insulation isn’t expensive, but if you build with a general contractor who charges a premium for it, that can ruin the budget. Those who build with timber framing basically have the "KfW 40" wall as standard. Monolithic construction requires thicker walls and therefore loses space due to the bulky structure.
- An air-to-water heat pump is also an option; it doesn’t have to be a ground-source (geothermal) heat pump.
- If the overall concept is coherent, a ground-source heat pump can be cheaper since the drilling depth may be shorter.
- Are the KfW loan conditions attractive? The conditions were poor for the last two years but are now good again, sometimes even better than bank loans.
- Do you expect rising heating costs regardless of the energy source? If your consumption is low, these increases don’t matter much. The resale value can also benefit—starting in 2021, only passive houses qualify, and KfW 40+ standards are very close to that today. Check listings on real estate platforms for new builds from five years ago: look at their energy ratings and compare them to current KfW 55 standards—this influences buyers’ perceptions significantly.
Similar topics