Air-Water Heat Pump - Experiences

We would like to use a geothermal heat pump, the problem is that our general contractor cannot guarantee a fixed price for the drilling, nor can the drilling company. So, on top of the current extra cost of €7,500 (geothermal heat pump + drilling - subsidy), something else could quickly come up that we cannot calculate.

Although I am not convinced of a geothermal heat pump in a single-family house, it does surprise me that the drilling company does not want/cannot specify exact costs. They must have experience values, right...? So far, in all the offers from drilling companies available to me, I always find a fixed price, as well as a tolerance of "x" drilling meters, contractually guaranteed. Rhineland regards

"With a heating load of 10 kilowatts, the air-to-water heat pump costs around 13,000 euros, and the operating costs are about 1,100 euros. For comparison, the gas condensing boiler costs around 4,500 euros with annual operating costs of 1,800 euros. The additional investment must be offset by the heating cost difference of 700 euros per year. That means the system pays off after about twelve years, although the interest on the additional investment is not yet taken into account."

In addition to the interest, compensation measures required by law must also be considered. The gas connection can also possibly be omitted. In our case, according to the builder's information, the "gas" option would have been about the same or more expensive than the air-to-water heat pump option (this refers to the investment costs -- of course, this can be different in other cases with other providers). If the air-to-water heat pump then really has lower operating costs (who knows), then everything will be just fine.

The website "Heizungsvergleich" lists many types of heating systems and clearly distinguishes between investment costs and operating costs and also considers the "cheapest" option over time. Take a look there.

So we will also build with an air-water heat pump since there is no gas in the street. Therefore, I have no experience yet. A colleague of mine has been living for 1 1/2 years in a house with a Stiebel Eltron with 9.7kW output for over 200m² of living space (without controlled residential ventilation) and comes to around €80 costs for heating and hot water without solar thermal or photovoltaic. It all depends on the appropriate sizing and fine-tuning. With an air-water heat pump, a precisely selected and then properly adjusted system seems to be the most important thing.

"The payback period of the heat pump depends on the individual case, a comparison: "With a heating load of 10 kilowatts, the air-to-water heat pump costs around 13,000 euros, with operating costs of about 1,100 euros. By comparison, the gas condensing boiler costs about 4,500 euros with annual operating costs of 1,800 euros. The difference in heating costs of 700 euros per year must cover the additional investment. That means the system pays off after about twelve years, with interest on the additional investment not yet taken into account."

A brine/water heat pump as well as a water/water heat pump have lower operating costs; however, the initial investment is higher. So if electricity prices become high, choosing the heat pump was the wrong decision.

Rhenish regards

Hello Bauexperte,
I ask you for your advice or opinion.

Our situation is as follows:
New build according to the Energy Saving Ordinance 2016, hollow brick, no basement, 155m² living area, underfloor heating and pellet stove in the living area, 2 adults, 1 child (possibly a second one to come).

1. Viessmann gas condensing solar package Vitodens 343 F11 incl. 2x Vitosol 200-FM for domestic hot water support (Energy Saving Ordinance 2016) incl. commissioning and gas tank (alone 2700,- euros since no connection is available).
12,800 euros gross
or:
2. Viessmann Vitocal 222-S air-to-water heat pump incl. Vitotronic 200, Vitoconnect 100 as well as Vitocell 100-E SVP (46L), without solar thermal, without ventilation:
9,200 euros gross.
Air-to-water heat pump thus 3,600 euros cheaper in initial investment, plus elimination of chimney in the utility room, lower maintenance costs, interest etc.
Actually a clear decision, isn’t it??

Am I overlooking something? OK, the small 160L hot water tank of the air-to-water heat pump worries me a bit as well as the noise of the "outdoor unit" (as usual).

You see, I’m certainly no expert, all information given to the best of my knowledge and belief.
Thanks in advance!