Supplement to my previous scope:
I have read that some people in the forum have experience with the air-to-air heat pumps (Proxon) from Zimmermann. Maybe someone can help me with my two questions:
The heat pump also heats the drinking water in the connected hot water storage tank. For the 300-liter hot water tank, there is an optional boost function. In this case, the heating element is replaced from 1.5 kW to 4.5 kW in order to heat the water faster if needed. The heating element is switched on when the heat pump’s capacity is not sufficient to bring the water to a certain temperature (or if it is turned on manually).
This function was recommended to us since we are building with a granny flat.
We are a family of two, and in the granny flat, presumably two more people will live.
Now my question is whether this boost function really pays off for us.
The second question concerns the cooling function of the system. Here, too, the question arises whether it can be dispensed with. It will probably have to run for a long time to have any effect at all and will accordingly consume a lot of electricity.
In addition, the cooling function in our offer says in brackets “Effizienzhaustandard beachten!”.
That means if we decide on this function, we also have to install more photovoltaic modules on the roof to balance the consumption again, otherwise we will no longer be eligible for KfW40 funding.