ᐅ Air-to-water heat pump, hydronic pellet stove, and photovoltaic system

Hello everyone,

We will start the groundworks for our new house next week and have a technical question. My husband would like to have a pellet stove in the living room that is water-heated and can support the air-to-water heat pump. The reason is the comfortable heat and, of course, energy consumption.

We are also planning a photovoltaic system, with or without storage; we have yet to decide on that.

Our air-to-water heat pump is subsidized by BAFA, and the pellet stove might also be eligible for BAFA funding, but we are unsure whether BAFA supports both at the same time for new builds. Do you have any experience with this?

What are your thoughts on this topic? I don’t want to introduce unnecessary technology into the house, but retrofitting is quite difficult.

Key information:
177 sqm (1900 sq ft) solid construction townhouse
4 people (2 children)
Estimated electricity demand with air-to-water heat pump: 7000 kWh per year
Underfloor heating and no ventilation system
Water consumption normal (rather economical), rarely bathing, etc.

If you need any more information, just let me know. Thanks!!

If the air-to-water heat pump is funded by BAFA, it has an annual performance factor of over 4.5. In practice, it’s still around 4, which means you would convert 1 kWh of electricity into about 4 kWh of heat with the air-to-water heat pump. That’s why I think 7,000 kWh is completely exaggerated; depending on your house’s energy demand, I would expect less than half that amount. Economically, using pellets would not be cost-effective.

ares83 schrieb:
If the air-to-water heat pump is BAFA-subsidized, it has an annual performance factor above 4.5. In practice, it’s still around 4. That means you would get about 4 kWh of heat from 1 kWh of electricity with the air-to-water heat pump. So I consider 7000 kWh to be completely exaggerated; depending on your house’s energy demand, I would expect less than half of that. Economically, pellets wouldn’t be worthwhile.

Thank you for your response. Our energy saving regulation calculation specifies a consumption of 4000 kWh for the air-to-water heat pump. I included a total of 7000 kWh by adding regular electricity consumption. I also believe the stove isn’t worthwhile and would rather be a gimmick, especially since we still plan to install a photovoltaic system.

The stove is more of a gimmick. You would need a large buffer tank for it, which doesn’t make sense with heat pumps. The additional cost of the stove, plus the necessary piping and controls, is so high that it won’t save any money.

Grants from Bafa for air-to-water heat pumps are rare. The annual performance factor must be proven, and achieving an air-to-water heat pump with a value above 4.5 is quite a challenge.

DanielaS schrieb:
If you need any data, just let me know.

Just out of curiosity: Energy Saving Ordinance 2016 or newer?

I wouldn’t necessarily count on the BAFA funding and would be more pleasantly surprised if it works out…

ruppsn schrieb:
Just out of curiosity: Energy Saving Ordinance 2016 or even better?

I wouldn’t necessarily count on the Bafa subsidy either and would be more pleasantly surprised if it works out...

Unfortunately, I cannot see that in the file. However, I found that the annual performance factor is 3.3. The total consumption of the air-to-water heat pump is 4,300 kWh.