Heat pump vs. heat pump + domestic water heat pump

Hello everyone,

I would like to get one or the other opinion. We bought a wooden prefab house from 1977.

It has 8cm insulation in the exterior wall, as well as in the first floor ceiling and attic (floor).

We want to additionally insulate the basement ceiling and the floor of the attic better.

A heating load calculation will be done in advance.

We are a household of 3 people and in 2024 we consumed an average of 1.625m³ of hot water per month. So about 18L/day/person.

Now to the actual topic: We are faced with the choice of installing a heat pump or a heat pump and a domestic hot water heat pump.

The advantage of the latter is that the heat pump can be smaller and thus more efficient.

The disadvantage I see is that I have two devices that can break down instead of one?!

The advantage of the latter is that the heat pump can be smaller and thus more efficient.

No. You basically size the heat pump according to the heating load, since the heat pump does not heat during the domestic hot water preparation. So it does not do both at the same time. Two heat pumps mean double the cost in the end without added value. No advantage. Or are there special circumstances in your case?

Do you have an example of a special feature? I don't know of any special feature. Thanks to you first for the contribution. That helps me a lot.

Do you have an example of a special feature?

(Damp) warm basement. The domestic water heat pump is located indoors and needs heat. So it cools rooms and dries them in the process.

Ah okay, no the basement is unheated.

My neighbor is happy that his unheated basement is now much drier. Also four degrees colder but just no longer musty.