Which heating system is currently the best?

Why "everything"? This is happening to me for the first time. My PC and the forum here seem to have not yet synchronized ( I have been intensively involved in the topic "house + heating" since 2005 ...for the purpose of broadening my horizons. And I have already realized a nice practical project ...with permanently affordable energy costs and a high feel-good factor ...affordable! )

Well, if I had my own wood, I would probably have done that too. So I just burn a few logs every now and then (about 2 cubic meters/year).

If you have to buy wood, I think it is no longer profitable (unless you have a secure source with "super cheap" prices).

I think for a new single-family house, you will most likely have to decide between geothermal energy and gas. Or if it’s heading towards a passive house, possibly an air heat pump or solar coverage.

Do you think that a nowadays standard energy-saving house 55-70 as a timber frame prefabricated building with an air heat pump plus additional support from a wood stove and controlled ventilation including a 6kWh producing photovoltaic system is the right choice for a new building? That's how I have planned it now. What do you think about it?

What do you say about this?

First of all, the actual demand (power, energy) for heating, hot water, ventilation must be determined here! Building, climate location, and user behavior are directly related. A one-sided and separate consideration usually leads to avoidable, excessive consumption and investment costs.

Best regards.

You ask for our opinion ... here is mine: - Kfw70 is the renovation case for the day after tomorrow ... I advise at least KfW55# - I like timber frame prefabricated construction, because achieving more insulation effect is also very easy there ... mostly you can simply take the external insulation thicker (e.g. 100mm instead of 60mm); moreover, this construction type has a low wall thickness with high insulation effect - saves space and lets more sun in. - Air-source heat pump depends on the region and is usually not so great with KfW70 ... but it also depends on a few other factors (e.g. where you live, how "winter-cold" it is there, whether well planned). - Controlled residential ventilation/heat recovery is in my view a "must be" today; I would consider FRG (moisture recovery/regulation) with it and definitely a soil-air heat exchanger. - Photovoltaics is not part of the heating/warmth concept in my view, but rather an investment to be considered separately (investment). (PS: 6kWh is nothing ... 6kW system output is something, it delivers about 5,500-6,000kWh/a) Question: Would geothermal work for you and if yes why didn't you choose it? Regards -Martin-

Try to summarize...

An air-to-water heat pump is not suitable as heating for a Kfw 70 house located in the Alps or Harz. Where temperatures often fall below -15°C in winter, an air-to-water heat pump (depending on the winter) could be borderline (but still cheaper than gas, although the advantage of the air heat pump is significantly reduced). Actually, it can only be operated without problems in the climate-favored areas of Germany.

Unfortunately, the last winters have been somewhat colder, making air heat pumps less efficient, which the air heat pump manufacturers probably did not expect (because of global warming).

As far as consumption costs are concerned, an air-to-water heat pump still seems to have enough leeway compared to a gas heating system (1/4 lower consumption costs in central Germany). Taking into account the additional acquisition costs + possibly accruing loan interests, screed drying, etc., an air heat pump (130 sqm house) only pays off after more than 10 years.

Therefore, an air-to-water heat pump is best suited in a passive house or Kfw40 house and can be safely operated throughout Germany.

Can we leave it at that? Correct me if I’m wrong...