Air-water heat pump, water-based pellet stove, and photovoltaic system

Hello everyone,

We are starting the earthworks for our new house next week and still have a technical question. My husband would like to have a pellet stove in the living room that is water-connected and can thus support the air-to-water heat pump. The reason is the pleasant warmth and of course the energy consumption.

We are also planning a photovoltaic system with or without storage; we will decide on that later.

Our air-to-water heat pump is subsidized by BAFA, and the pellet stove might also be subsidized by BAFA, but we are not sure if BAFA supports both things simultaneously for new buildings. Do you have any experience with this?

What are your opinions on this topic? Of course, I don’t want to bring unnecessary technology into the house, but retrofitting later is very difficult.

Key data: 177sqm solid construction city villa 4 people (2 children) Estimated electricity demand with air-to-water heat pump 7000 kWh per year Underfloor heating and no ventilation system Normal (rather economical) water consumption, rarely bathing etc.

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

If the air-to-water heat pump is subsidized by BAFA, it has an annual performance factor of over 4.5. Even in practice, it's still around 4. That means you would convert 1 kWh of electricity into 4 kWh of heat with the air-to-water heat pump. I consider the 7000 kWh totally exaggerated; depending on your house's energy demand, I would expect less than half of that. Purely economically, it won't be worthwhile with pellets.

If the air-to-water heat pump is BAFA subsidized, it has an annual performance factor of over 4.5. Even in practice, it is still around 4. This means you would convert 1 kWh of electricity into 4 kWh of heat with the air-to-water heat pump. I consider the 7000 kWh totally exaggerated; depending on your house's energy demand, I would calculate with less than half. Economically, it will not be worthwhile with pellets.

Thank you for the answer. Our Energy Saving Ordinance calculation specifies a consumption of 4000 kWh for the air-to-water heat pump. I have submitted a total of 7000, including regular electricity consumption. My understanding is also that the stove is not worthwhile but rather a gimmick, especially since we are going to install a photovoltaic system.

The stove is a gimmick. You would need a large buffer storage for it, which makes no sense with heat pumps. The additional cost of the stove, the necessary piping and control is so much more expensive that nothing will be saved with it.

Bafa for air-to-water heat pump is rare. The annual performance factor must be proven, and an air-to-water heat pump with >4.5 is quite an art.

If you still need data, just let me know.

Just out of interest: Energy Saving Ordinance 2016 or better? I wouldn’t necessarily count on the Bafa subsidy now and would rather be pleased if it should work out...

Purely out of interest: Energy Saving Ordinance 2016 or better?

I wouldn’t necessarily count on the Bafa subsidy now and would rather be pleased if it works out...

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