LWW, gas or geothermal operating cost experiences

We also had a long discussion about whether to choose an air-water heat pump or gas. Even geothermal energy was considered for a short time. After we had already decided on an air-water heat pump, we switched to gas. And I have to say, that was absolutely the right decision and I have not regretted it.

With 250m² of space, we used a good 11-12m³ of gas per day when it was -18 degrees. That’s 4€ on the coldest day. By the way, without exterior plaster at that time, just moved in. Currently, we are at half that. I am sure the neighbors with their air-water heat pumps stood nervously in front of their electricity meters during that time... I have heard of costs of 150€ per month.

For us, the air-water heat pump would never have paid off. The air-water heat pump would have cost us 1800€ more despite the gas connection. Converted: in the next 15 years I will not make that money back with the air-water heat pump, which by the way has a service life of about 6-7 years. Most do not last longer because the compressor breaks down earlier -> cost several thousand €. Of course, something can break with the gas heating as well, but consider: the technology has existed for decades, is mature, and a completely new gas condensing boiler costs 4000€. No KFW55 with gas is also nonsense! Just search for Stiebel Eltron Energy Saving Ordinance system consultant... there you will see that you can manage that with gas. You just need a bit more insulation or more collectors. And I would rather invest the money in better insulation than in technology that will break down... sooner or later.

Geothermal energy alone would have cost us almost 10,000€ for the drilling. You will never ever get that back. That is purely for idealists. Great idea, but economically total nonsense.

And note: with the air-water heat pump you don’t get any subsidies, only with geothermal. Some will now shout... but that’s wrong. I called BAFA at the time and have it in writing that a subsidy for the air-water heat pump is only granted (1500€) if the air-water heat pump achieves an annual performance factor of 4.5 or higher. Unfortunately, no air-water heat pump achieves that. You barely achieve that with geothermal.

And one more thing: our chimney sweep only has to come every 3 years... so that is no longer really an argument today.

Have fun with the decision... I know how tough it is and I am glad to have it behind me and to have made the right decision for me.

And note: with the air-to-water heat pump you do not get any funding, only with geothermal energy. Yes, some will now shout... but that's wrong. I called Bafa back then and have it in writing that funding for the air-to-water heat pump is only granted (1500€) if the air-to-water heat pump achieves an annual performance factor of 4.5 or higher. Unfortunately, no air-to-water heat pump achieves that. You can only barely manage that with geothermal energy.

Unfortunately a false statement. We have a funding approval here from BAFA for our air-to-water heat pump. So ours has, at least theoretically, and that is the decisive factor for the funding, an annual performance factor of 4.5.

Unfortunately a false statement. We have a funding commitment for our air-to-water heat pump from BAFA. So ours has, at least theoretically, and that is the decisive factor for the funding, an annual performance factor of 4.5.

Okay, that may be. But for many, it is not enough. It depends on the device.

As far as I know (but I am not yet fully informed because we are not quite that far along), you cannot get KfW55 funding (or better) with fossil fuels but at most KfW70. That should perhaps be taken into consideration. But, as I said, I am happy to be corrected

That is not correct. We are building a house to KfW55 standard and are using only a gas condensing boiler without solar. Instead, we have preferred to invest a bit more in insulation.

That's not correct. We are building a house according to the KfW55 standard and are only using a gas condensing boiler without solar. Instead, we preferred to invest a bit more in insulation.

Where does the renewable share come from? Biogas? Controlled residential ventilation with heat recovery?

Controlled residential ventilation with heat recovery
I should have added that, sorry.