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!
G
Grantlhaua5 Apr 2019 12:57I think this is a very good solution! It's a pity that KFW wasn't an option for us last year... you could then invest the 5,000€ in a pool table or something else nice :P
robin1988 schrieb:
I want to briefly share the concept we will most likely implement:
A gas condensing boiler combined with solar thermal energy and mechanical ventilation with heat recovery. Additionally, we will adjust the building components to meet the reference values required for KFW 55 certification. Solid planning without major experiments.
We are building exactly the same way.
We obtained KFW 55 certification without any problems.
M
Mottenhausen5 Apr 2019 14:13robin1988 schrieb:
I want to briefly share the concept we will most likely implement:
Gas condensing boiler with solar thermal system and controlled mechanical ventilation with heat recovery. Additionally, the building components will be adjusted to achieve KfW 55 standard based on reference values.
Exactly like us! After the thermal bridge calculation by the energy consultant, the insulation thickness could even be reduced. We now have 24cm (9.5 inches) hollow bricks and 12cm (5 inches) external thermal insulation composite system (ETICS), resulting in a standard 36cm (14 inches) wall thickness with thermal transmittance as low as that of an almost twice as thick monolithic wall...
H
hampshire5 Apr 2019 16:41robin1988 schrieb:
Would you still say that a KFW 40 plus house based on these values is not economically viable? Hello Robin,
I really like your question because it sets financial considerations aside for a moment and allows us to focus on other criteria.
I assume you want to live in your house. Therefore, consider at least four criteria and prioritize them:
1. Indoor health
2. Living comfort
3. Ecology
4. Cost-effectiveness
What does your ideal energy supply for heating and electricity look like?
We arrived at a solution outside the KFW standards, implemented with modern methods, CO2 neutral, and permanently affordable for us in operation (10kWp photovoltaic system with solar tiles, 2 wood stoves, 1 masonry heater, a few infrared heating panels, wood regrows on the property faster than needed, 2 instant water heaters, and 1 hot water heat pump with storage). We did not calculate the return on investment for construction costs because this solution also includes aesthetic elements, which makes comparison difficult. How do you price a stove? You don’t usually evaluate the cost-effectiveness of a piece of furniture or a wall covering either.
hampshire schrieb:
10 kWp photovoltaic system with solar roof tiles@hampshire may I ask which solar roof tiles you are using?
H
hampshire5 Apr 2019 22:01I don’t think I’m allowed to say, as I received a negative point for it in one of my first posts.
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