ᐅ The heating options – air-to-air heat pump, air-to-water heat pump, or gas?

Wood, stone, or concrete?

Wall construction?

Primary energy demand?

In my opinion, unless you build significantly below the KfW-70 standard, gas offers the best cost-performance ratio in our region...

We also have a KfW-70 house and saved around 10,000 on the extra cost of a heat pump, so we can heat for a while with that...

In my opinion, most people are best advised to use gas.

There are now providers whose concept "cannot live without gas" (the primary energy demand often does not comply with the typical KFW 0815 label). In this case, an air-to-water heat pump might be acceptable. Adding photovoltaics is not entirely unreasonable. However, investment costs are somewhat higher than with gas plus a small storage tank – operating costs are roughly the same (of course, this depends on the size of the photovoltaic system).

There are also concepts for the air-to-air heat pump. An air-to-air heat pump can be a solution with relatively low investment costs when used in the right house. The solutions become more robust against planning errors from bottom to top.

Regarding the points you raise:

• Low operating costs come at the price of high investment costs.
• The possibility to install "modern" (i.e., low supply temperature?) heating systems via underfloor heating is also available with gas – nothing prevents you there from using short pipe spacing and low supply temperatures. However, the "most modern" type of heating system is the air-to-air heat pump – which currently doesn’t require underfloor heating at all ;-)
• I unfortunately cannot comment on indoor comfort as I have never lived in a house with ventilation heating (at least not in one that was anything but extremely poorly insulated).

I agree with the previous comments: A bit more information about the construction method and the intended KfW standard would be great. 😉

We use gas for heating. Our underfloor heating was installed in tight loops to allow the possibility of switching to a different heating system later on. However, we had considered a brine-to-water heat pump for a long time.
Because we didn’t invest in the brine-to-water heat pump, we will be able to heat with gas for a very, very long time. 😉

Choosing the heating system is also a matter of gut feeling and personal preferences.

Mycraft schrieb:
Wood, stone, concrete?

Wall structure?

Primary energy demand?

In my opinion, if you don’t build well below the KfW-70 standard, gas offers the best cost-performance ratio in our regions...

We also have a KfW-70 house and saved about 10,000 euros (around $10,000) by not choosing a heat pump, so we can heat for a while now...

I cannot understand the 10,000 euro (around $10,000) extra cost you mention.
An air-to-water heat pump (with a 200-liter (53-gallon) hot water tank) costs about 10,000 euros (around $10,000) for equipment (roughly 5-9 kW capacity), but a condensing boiler (without a water storage tank) also easily costs at least 2,000 euros (around $2,000) if you choose a branded unit. On top of that, there are probably at least 1,000 euros (around $1,000) additional costs for air intake and exhaust ducting (you can clarify the exact costs, or others can, since I no longer have gas).
Additionally, there are the gas connection costs, which vary widely depending on the city, but overall you’re likely to spend another >1,000 euros (around $1,000).
If you don’t already have a mechanical ventilation system with heat recovery planned, or if you aim to build beyond the requirements of the Energy Saving Ordinance, you’ll quickly need solar thermal systems, which also add significant costs.
All in all, the savings at construction are limited. Heating with gas is obviously not much cheaper than with an air-to-water heat pump.
So you should decide not based on finances alone, but according to your situation: starting with the most important point — “is gas even available?” (our plot was offered and sold as “with gas,” but during connection after purchase, the utility company told us it wasn’t worth it because there was no gas — I would have liked to cook with gas). Then, of course, ideology comes into play (do you want “fire”? Do you prefer only “renewables” and opt for an air-to-water heat pump with “green” electricity, etc.). Also consider location and surroundings — where are you building? (Please don’t put an air-to-water heat pump up in the Alps, for example) — and so on.

Nobody can really explain the deals with the GÜs (general contractors) and their additional charges... a price is simply given, and there is little to nothing you can do except accept it or leave it.

For us, the difference between a gas boiler with solar thermal system and a full air-to-water heat pump was 10,000 (ten thousand) euros.

So, we invested around 1,500 euros in the gas connection and that was it... effectively saving almost 10,000 euros.

The mechanical ventilation system was supposed to cost 12,000 to 14,000 euros, but in the end, we installed one for half that price through an external ventilation company that we hired ourselves.

If the heating system is properly planned and installed, it is actually one of the easiest things to get right. The potential savings on heating costs in new construction are now very small—around 100 or 200 euros per year! This should hardly be a concern for anyone who can afford to build a house. In other words, you can fully focus on your existing conditions when choosing the heating system.

If the builder or energy consultant offers an air-to-water heat pump, it will fit the concept well, so just go with it. If they prefer gas, they have likely had good experience with it, so that’s fine too.

If you are not choosing an off-the-shelf solution, then look at your specific conditions: basement yes/no, gas connection available, possibility for pellet storage, noise constraints at the installation site, KfW guidelines (German development bank), and so on, and then select a suitable system.

In short, the economic factor regarding operating costs is your least concern ;-)