Air-to-water heat pump sizing in new construction

not for geothermal energy?

Not up for discussion. Why and with what intention do you ask?

Not up for debate. Why and with what intention do you ask?

With us, the planning for the house construction is slowly approaching and I am pondering whether I should insist on geothermal energy or an air-to-water heat pump. The more you read, the more uncertain you become. The type of heating is not a decision you change daily. I can replace the model of the toilet every day for a few euros, but the heating will have to run for several years and planning errors here can become very quickly very expensive.

When we bought the plot, I contacted the responsible authority beforehand and inquired whether deep drilling was allowed. This was confirmed to me and I was informed that there was nothing against it. After that, we also chose our plot accordingly. It is pointless to buy a plot if the construction project ultimately does not conform to the development plan.

When I read up on the topic back in 2019, the problems with the efficiency of air-to-water heat pumps at low temperatures were repeatedly pointed out. The advantage of deep drilling is the constant temperature. But when I read here in the forum, I read 99% about air-to-water heat pumps or a trench collector. Also, in the new incentive program 2021, I no longer read anything about the funding of geothermal drilling.

We do not want the trench collector because we would have to pay too much attention to planting (root depth). Although the space with over 1000 m² would be given, currently I just can’t get enthusiastic about it.

I have completely ignored the problem of noise development of an air-to-water heat pump, since on two sides we have no neighbors, only fields. So that would not be a problem for us.

The disadvantage of deep drilling is precisely the higher costs.

But no one can predict the temperatures for the next 20-25 years. This winter in northern NRW we had -23°C and in 2012 we had -16°C. Unfortunately, no one knows what the coming winters will bring and I would rather not keep my winter warm with the "heating rod."

The trench collector is ideal for you. You don't have to worry about root depth there, the collector is laid at about 180 cm...

The trench collector is predestined for you. You don't have to worry about root depth there, the collector is laid at about 180cm...

1.8m??? :oops: I always thought that the collector is rather buried at about 1m. Do you have tips on what I should search for to educate myself on the topic?

Won't the whole ground be dug up and the layers (topsoil/fill soil) mixed then?

As of today, in my opinion, the air-to-water heat pump is the second cheapest heating option after the gas heating system, in terms of investment and economic operation. At the time, we deliberately wanted to decide only between gas and a heat pump.

The topic of geothermal energy is not approved by the water authority in our area. The topic of the trench collector was always interesting to me, but was discarded due to the then BAFA subsidy. It either was not possible or would have become too complicated due to the own work required for the trench.

With proper design of the underfloor heating (have the room-specific heat load calculated by a professional!) and selection of the right heat pump, operation and costs should be extremely favorable in the current climate. In OWL it is usually quite warm in winter (except this year), so that the electric heating element only has to help in exceptional cases. I assume that in the future there will be more warm than cold winters and the efficiency of the air-to-water heat pump will increase. If it turns out that the opposite is the case, I would consider the trench collector afterward. The technology is reasonably easy to replace if the underfloor heating is optimally installed. Very roughly estimated, you could get the trench collector + heat pump for the additional cost of the drilling.

Especially when using the collective intelligence on the internet, good and inexpensive solutions can be realized in reinvestment without involving the general contractor, if the air-to-water heat pump should be the wrong solution due to climate.

Best price-performance winner if you don't want gas: air-to-water heat pump

With us, the planning for the house construction is slowly approaching and I am wondering whether I should insist on geothermal energy or an air-to-water heat pump.

As always with such questions, my note:
More important than the heat source is the insulation of the house and the design of the underfloor heating and the heat pump.
If that doesn’t fit, even the best heat source is of no use.