Is a buffer tank useful in a heat pump?

Exactly the same points are going through my mind:

- Ask neighbors and compare what is different
- Carry out hydraulic / thermal balancing

Just no combi-storage, another forum is full of unhappy owners of a combi-storage...

Just no combi storage tank, another forum is full of unhappy owners of a combi storage tank...

Due to the small domestic hot water tank of 165 liters, I tend to prefer a storage tank with an internal domestic hot water coil.

Of course, I would prefer if a fault (dirt trap heating circuit/brine circuit, temperature sensor, overflow valve, ...) is found that caused the many starts/stops, which can be fixed, so that I do not need any buffer tank at all to solve the problem.

There is nothing against a larger hot water storage tank with or without a fresh water station. For this, no stratified storage tank/combination storage tank is required. These are then also installed as a hydraulic separator.

There is nothing against a larger hot water storage tank with or without a fresh water station. For that, you do not need a stratified storage tank/combined storage tank. These are also installed as a hydraulic separator.

We were recommended a buffer tank for the heating system to prevent the many cycles. If I now only take an expansion of the hot water storage tank, I would be ignoring this recommendation.

My thought was to take a combined storage tank because
- many cycles can also occur in hot water preparation.
- the hot water storage tank with 165 liters is very small for 5 people.

Or do you think one should take a buffer tank AND (separately) an expansion of the hot water storage tank?

- the hot water storage tank with 165 liters for 5 people is indeed very small.

I wonder anyway how you managed with that in the past. When I shower extensively with my three children (which takes a while with three girls with long hair), our 300l tank is almost empty or down to 25 degrees.

I just finished reading the thread completely. Actually, only a properly large buffer tank for the heating remains as a solution for a messed-up heating planning. With a 3kW lower modulation limit for the well-insulated house, the heat pump has no choice but to cycle heavily, so you can almost watch it age rapidly (keyword compressor starts).

I would actually work with two separate tanks and as soon as the heat pump needs to be replaced, switch to a significantly smaller unit and disconnect the heat pump buffer again.