Is a buffer tank useful in a heat pump?

Maybe I overlooked that it MUST be repaired.

The compressor is defective and therefore no heating (at most heating element).

The compressor is defective and therefore no heating (at most heating element).

The heating element works only moderately. Hot water is at 32°.

A electric heating element should always keep the thing running at least, is there more wrong?

Anyway, such a replacement is done by 2 people in 1.5 days if they know what they're doing. It also always depends on the region where you are and how arrogant the plumbers are at the moment.

In your case, I would choose a different concept. Heat pump as a solo device, 280 l domestic hot water storage tank, that's it. In a single-family house you have enough throughput, so you normally don't have to worry.

Costs: I replaced an air pump half a year ago, costs are similar, it was 18 all-in gross. Whether you get by with a 4 kW pump, you have to calculate that exactly, it's already quite a bit cheaper.

Hmh, on closer inspection one could also come to the conclusion that a new heat pump increases efficiency, and then you’re dealing with the kfw, which suddenly makes it more interesting... there is a leaflet on heating subsidies for private individuals – residential buildings

Annual performance factor: 4.6

Hmm, on closer inspection one could also come to the conclusion that a new heat pump increases efficiency,

Phew, that will be difficult...
I don't know how that could be seriously justified.

Whether a 4kW pump is sufficient, that needs to be calculated precisely, it is already quite a bit cheaper.

For the area, 4kW heating capacity is certainly not enough. He himself mentions a heating demand of 7-8kW. Otherwise, I think that during the transition period it is quite acceptable to intervene in the control and, in a spring thaw like this week, turn off the heating for a few days. With 13-15 degrees during the day and substantial solar gains, the heating demand is so low that every heat pump cycles.