How to efficiently plan heating for a new building?

What variants are there? Or what do you calculate per person?

For example, a fresh water station that works like an instantaneous water heater. Or classic hot water storage tanks that keep the drinking water directly at temperature. As a family with child(ren), I would always go directly for 300 liters. Smaller for a couple or single (200 liters).

Unfortunately, I couldn’t edit anymore. I still don’t quite understand the heat pump. How exactly is the water heated to 60 degrees, for example? Does this happen in the hot water storage tank then with electricity? Because the heat pump runs at 30 degrees. Or am I making a mistake here?

By the heat pump heating the heating water to e.g. 60 degrees, which then, via the 3-way valve, no longer circulates in the heating circuit but heats the DHW storage tank and returns through the return line to the heat pump.
Apart from that, in a single-family house, you normally go for about +/- 50 degrees.

The setup could look something like this. In this case, it is a monoblock; with split devices, there is an indoor part where the DHW storage tank may already be included – but in principle, it’s the same.

1. correct calculation of the heating load according to your wishes. For example, with a flow temperature of max. 30 degrees and your desired temperature in the house

By heating the heating water with the heat pump to, for example, 60 degrees, which then no longer circulates through the heating circuit via the 3-way valve, but heats the domestic hot water tank and returns to the heat pump through the return line.

Do I understand this correctly? The heat pump runs at 30 degrees when heating and briefly at 50 when the domestic hot water falls below a certain value? And the 3-way valve is controlled by the heat pump? That is the point I still don't really understand.

Do I understand this correctly? The heat pump runs at 30 degrees when heating and briefly at 50 when the hot water falls below a certain value? And the 3-way valve is controlled by the heat pump? That's the point I still don't really understand.

Exactly. And with most heat pumps you can also set, for example, blocking times when the heat pump is allowed to produce hot water and when not. Very useful for L/W heat pumps to shift hot water production to the time when most electricity comes from photovoltaics and outdoor temperatures are higher.

It would also be important that the heating circuit lengths are similar. Then the heating works more efficiently and don’t forget the wall heating in the bathroom.

Do I understand this correctly? The heat pump runs at 30 degrees when heating and briefly at 50 when the hot water falls below a certain value? And the 3-way valve is controlled by the heat pump? That’s the point I don’t really understand yet.

Where is my answer? I had written that the questions are formulated as statements, the answers are. Yes, the heat pump first heats and then switches to a hot water mode (when the temperature in the storage falls below a predetermined threshold). For this, it switches the valve and then heats the hot water tank.

By the way, it may be that the Heizi does not want to operate without a buffer due to manufacturer specifications. However, he should choose the buffer as small as possible and connect it in series to the return flow. That way, you have the least efficiency losses.

Hello,
my recommendation is towards a ground source heat pump. It should be somewhat more efficient than the air source heat pump.
However, you need a ground borehole for that. Possibly, if feasible, worth considering. It operates just like an air source heat pump.
Only that you don’t need a separate outdoor unit.