Hello everyone,
some background on my questions:
I am currently exploring the possibility of converting our house from a gas heating system to a heat pump. It might sound completely crazy for a house that is just under 7 years old, but this could be funded and financed as an “energy renovation project” together with a photovoltaic system through KFW 261. That could actually make it economically very attractive.
I am still in the evaluation phase and have started initial discussions with heating and solar experts.
This immediately raised some questions for me, because the first offers are quite contradictory to the principles I often see discussed here in the forum:
The insulation level of the house is about KFW 55 standard; however, the overall standard was not met back then due to the gas heating system. The heating demand is around 12,000-13,000 kWh for a total of 270 square meters (2,900 square feet). There is underfloor heating throughout, including the basement.
Best regards,
Andreas
some background on my questions:
I am currently exploring the possibility of converting our house from a gas heating system to a heat pump. It might sound completely crazy for a house that is just under 7 years old, but this could be funded and financed as an “energy renovation project” together with a photovoltaic system through KFW 261. That could actually make it economically very attractive.
I am still in the evaluation phase and have started initial discussions with heating and solar experts.
This immediately raised some questions for me, because the first offers are quite contradictory to the principles I often see discussed here in the forum:
- Buffer tank (heating water) – Question: What exactly is the purpose of this and when does it make sense? So far, no seller has been able to clearly answer this, although the technical answer is simple: it should act as a hysteresis to reduce short cycling of the heat pump. The general idea is understandable, but I don’t really see how 100 liters (35 gallons) of buffer tank help when just the volume of my underfloor heating system already exceeds 200 liters (70 gallons), plus the large mass of screed acting as thermal storage. The current gas heating system works fine without a heating buffer tank.
- Heat pump capacity and modulation – the first quotes naturally come with absurdly oversized heat pumps because they only consider the total heated area of 270 square meters (2,900 square feet). When I point out that 12 or even 16 kW seems excessive, the answer is always: “It can modulate down from 3 to 12 kW.” That’s fine, but exactly this modulation is often warned against. So question: why is modulating down performance considered a problem? Is this the short cycling that people warn about? Technically, modulation means the entire system, including the compressor and all components, runs slower. But then the question arises how efficient it still is.
The insulation level of the house is about KFW 55 standard; however, the overall standard was not met back then due to the gas heating system. The heating demand is around 12,000-13,000 kWh for a total of 270 square meters (2,900 square feet). There is underfloor heating throughout, including the basement.
Best regards,
Andreas
R
RotorMotor5 Nov 2023 19:46Karlsson schrieb:
What would be your recommendation then?We have a 300l (79 gallons) tank. It works well. However, in hindsight, I would have preferred to use a fresh water station or an appropriate storage tank. The issue with Legionella bacteria is quite annoying and could have been managed much better with that.
Hello everyone,
I have now received a reasonably well-founded assessment. So:
It is indeed possible to finance both a heat pump and photovoltaic system through the KFW 261 program. Depending on the achieved efficiency class, there is a 15-25% subsidy and for the remainder, a loan with 0.24% (!!) interest. This is quite interesting.
But:
If the photovoltaic system is financed through a KFW loan, you no longer receive feed-in compensation. Therefore, it makes little sense (as is often demanded in a well-known photovoltaic forum) to “fill the roof to the maximum.” Instead, the system should be designed to maximize self-consumption.
I am still calculating. The loss of feed-in compensation is obviously painful, but it’s less dramatic than it first appears. The ROI shifts from 11-12 years to about 13-14 years. Still significantly better than a photovoltaic system financed with own funds, which hardly ever achieves an ROI below 20 years.
Best regards,
Andreas
I have now received a reasonably well-founded assessment. So:
It is indeed possible to finance both a heat pump and photovoltaic system through the KFW 261 program. Depending on the achieved efficiency class, there is a 15-25% subsidy and for the remainder, a loan with 0.24% (!!) interest. This is quite interesting.
But:
If the photovoltaic system is financed through a KFW loan, you no longer receive feed-in compensation. Therefore, it makes little sense (as is often demanded in a well-known photovoltaic forum) to “fill the roof to the maximum.” Instead, the system should be designed to maximize self-consumption.
I am still calculating. The loss of feed-in compensation is obviously painful, but it’s less dramatic than it first appears. The ROI shifts from 11-12 years to about 13-14 years. Still significantly better than a photovoltaic system financed with own funds, which hardly ever achieves an ROI below 20 years.
Best regards,
Andreas
Hi,
Interesting idea. So far, I have only read that you are not allowed to take the feed-in tariff. There was no mention of direct marketing. It would still need to be clarified whether that is allowed, since in the end it is also a form of feed-in remuneration, right? I definitely can’t reach 30 kWp; on the house roof I can get a maximum of 16-17 kWp, and maybe another 5-6 on the carport. That’s it.
Best regards,
Andreas
Tolentino schrieb:
direct marketing?
I read somewhere that from 30 kWp there are partners with whom you can then make direct supply contracts.
Interesting idea. So far, I have only read that you are not allowed to take the feed-in tariff. There was no mention of direct marketing. It would still need to be clarified whether that is allowed, since in the end it is also a form of feed-in remuneration, right? I definitely can’t reach 30 kWp; on the house roof I can get a maximum of 16-17 kWp, and maybe another 5-6 on the carport. That’s it.
Best regards,
Andreas
Feed-in tariff is a form of support because it guarantees you a fixed price per kilowatt-hour for 20 years.
Direct marketing is a regular business transaction. I produce electricity, you buy it from me. Terms are freely negotiable (although for very small suppliers, like single-family home users typically are, you are dependent on the direct buyer partners).
Check with EnbW for information; apparently, it is available from 15 kWp (15 kilowatts peak)...
Direct marketing is a regular business transaction. I produce electricity, you buy it from me. Terms are freely negotiable (although for very small suppliers, like single-family home users typically are, you are dependent on the direct buyer partners).
Check with EnbW for information; apparently, it is available from 15 kWp (15 kilowatts peak)...
Hello,
here’s a quick update:
The tip about direct marketing was great, thanks!
But: While the idea sounds excellent in theory, it now seems to be failing in practice. For the planned measures, we would need around 55,000 euros minus the repayment subsidy, so about 43,000–45,000 euros KfW loan. However, banks won’t do that. My main bank clearly said they don’t grant KfW loans under 75,000 euros, and even brokers like Dr. Klein confirmed this. They told me that most banks want to provide an initial 50,000 euros loan on their own terms before issuing KfW loans.
Hmm… difficult. Does anyone know a bank that passes on the KfW terms directly?
Best regards,
Andreas
here’s a quick update:
The tip about direct marketing was great, thanks!
But: While the idea sounds excellent in theory, it now seems to be failing in practice. For the planned measures, we would need around 55,000 euros minus the repayment subsidy, so about 43,000–45,000 euros KfW loan. However, banks won’t do that. My main bank clearly said they don’t grant KfW loans under 75,000 euros, and even brokers like Dr. Klein confirmed this. They told me that most banks want to provide an initial 50,000 euros loan on their own terms before issuing KfW loans.
Hmm… difficult. Does anyone know a bank that passes on the KfW terms directly?
Best regards,
Andreas