Is a buffer tank useful in a heat pump?

At 13-15 degrees during the day and with decent solar gains, the heating demand is so low that every heat pump cycles

3-4 cycles in 24 hours currently at up to 15 degrees during the day. But that is completely fine for the technology.

News: The neighbors, whose heating runs with 5 cycles per day instead of 25 cycles per day like ours, have a heating demand over the year that is 2.7 times higher. We have 12,740 kWh, they have 34,480 kWh. It is no wonder that their heating operates differently than ours. The size is fine for their needs, but not for us. The heat pump has a modulating capacity of 3-12 kW. A subsequent heating demand calculation for our house showed a heating demand of 6.3 kW. That would be an argument to completely remove the unit and install one of the appropriate size. Very annoying, this matter!

Brings you little, but why do the neighbors need so much more?

Can you still cancel the repair ordered for Tuesday?

4kW heating capacity is certainly not enough for the area. He himself mentions a heating demand of 7-8kW.

If you had read, with the data available to me, a heat load of 5 kW resulted (calculated without ventilation), with controlled residential ventilation even less. And then a 4 kW pump fits. So first it is necessary to clarify the 7-8.

Sorry, but with a 4kW heat pump you won’t manage even with controlled residential ventilation at a 5kW estimate. Longer periods with double-digit subzero temperatures are not as common anymore, but when that happens, will you then plug in the fan heater? For a house of that size, 5kW is also very optimistic.

- Data Energy standard: almost KfW-55 Annual primary energy demand Qp according to the energy saving regulation: 34.5 kWh/(m2a) specific transmission heat loss H'T: 0.305 W/(m2 K) Heated building volume 920 m^3 Living area: 220 m^2 Heated living area: 170 m^2 Controlled residential ventilation with heat recovery is available.

I bet someone roughly multiplied 220 * 34.5 and came up with 7-8. But that has not much to do with heat load calculation. And on the topic of better energy efficiency: well, I don’t need to be a great clairvoyant to know that if I install a modern pump according to today’s standards, it is more efficient than a 7-year-old box. If the new one is also properly sized (starting at 1 kW, not at 3), then I am definitely even more efficient.