ᐅ KfW 55: Choosing the Heating System – Gas vs. Air-to-Water Heat Pump
Created on: 21 May 2021 18:29
G
Gerddieter
Hello everyone,
we recently spoke with the general contractor about the quote for a KFW55 single-family house.
We’re uncertain about the heating system. According to the contractor, for the subsidy we need either an air-to-water heat pump or a gas boiler combined with a ventilation system and solar thermal.
The contractor couldn’t clearly explain the pros and cons, only that the air-to-water heat pump is more commonly used and the gas combination with ventilation is more expensive (but then you do get ventilation and solar thermal).
We would prefer to avoid having the air-to-water heat pump unit installed in the garden, but are generally open.
Could you please share your opinions on the advantages and disadvantages?
Thanks,
GD
we recently spoke with the general contractor about the quote for a KFW55 single-family house.
We’re uncertain about the heating system. According to the contractor, for the subsidy we need either an air-to-water heat pump or a gas boiler combined with a ventilation system and solar thermal.
The contractor couldn’t clearly explain the pros and cons, only that the air-to-water heat pump is more commonly used and the gas combination with ventilation is more expensive (but then you do get ventilation and solar thermal).
We would prefer to avoid having the air-to-water heat pump unit installed in the garden, but are generally open.
Could you please share your opinions on the advantages and disadvantages?
Thanks,
GD
nordanney schrieb:
I’m just saying CO2 tax. I’m just saying: This issue has been going on for decades, and strangely, electricity prices haven’t decreased either.
nordanney schrieb:
The demands from SPD and the Greens will make gas significantly more expensive than before. Demands versus reality... well, you can imagine the rest.
nordanney schrieb:
Why does everyone always say that gas is so cheap to install, and heat pumps are so expensive? Because the listed online price isn’t the whole story, and for gas it’s really just a little extra... but for heat pumps, it’s somewhat more (actually much more).
S
Strahleman21 May 2021 22:02Mycraft schrieb:
With today’s regulations and construction methods, always use mechanical ventilation with heat recovery.That’s exactly what I meant to imply. Our energy consultant told us that when building to KfW55 standards, you must use mechanical ventilation with heat recovery. Since we planned to use this type of ventilation anyway, I didn’t question it further, and I’m not sure if it’s actually mandatory.Mycraft schrieb:
Wishes and reality... well, you can imagine the rest.Well, the energy price increased by 20% at the beginning of the year due to the CO2 levy. The price hikes for the coming years are already set, and even the CDU is currently pushing for a faster increase of the levy. You’d have to be blind not to see that...
A gas boiler is certainly initially cheap as a device, plus the connection, the flue pipe, and solar thermal systems to cover the renewable portion. As a complete system, the investment difference isn’t that large.
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pagoni202021 May 2021 22:07Strahleman schrieb:
That’s exactly what I wanted to imply. Our energy consultant told us that for KfW55 standards, you have to build with controlled mechanical ventilation. Since we wanted to have controlled mechanical ventilation anyway, I didn’t question it further and don’t know if it’s really required. It is definitely possible to build without controlled mechanical ventilation. However, if you plan to include it anyway, it also makes sense because it positively affects the KfW calculation.
Therefore, I think it’s reasonable to implement what you want to install anyway and then see where the KfW calculation leads you. The statement “we are building a KfW house” doesn’t make much sense to me. In the end, it could even result in KfW40, or not.
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nordanney21 May 2021 23:29Mycraft schrieb:
a little more is involved, and with gas it really is very little... Except for the gas connection, which must be run from the street to the house. The chimney. You don’t need any of that with the heat pump. It’s not just the online price of the gas boiler. There’s quite a bit more involved.
In the end, both systems are quite similar in initial costs.
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