ᐅ Combination of Heat Pump and Ventilation System – What to Consider?

Make sure that the heat pump generates the heat, not the decentralized ventilation system.

Great, thanks for the feedback. I thought there might be something specific to set. I’ll just sit back and let the automatic system take care of it :-D

However, not every ventilation system includes a bypass. In some cases, it is only available as an optional extra for an additional cost.

Due to limited space, our ventilation system will now be changed to a ceiling-mounted model (Climos F200). This one does not have a bypass. I have tried to find information but there is hardly any available, and no real user experiences. I assume this is because it is intended mainly for small houses, which few people build like this. Since we have little choice, I just hope it will do its job and that we won’t overheat during the summer. I chose this system specifically to avoid having to ventilate manually.

Adjusting settings in winter without a bypass is not an issue because the ventilation system preheats the cold outside air, reducing the load on your heat pump. However, in summer it gets hot without a bypass: the ventilation system cannot automatically deactivate its heat recovery. This causes problems if your heat pump has a cooling function, as the heat pump tries to cool while the ventilation simultaneously brings heat back into the house.

Zehnder states that for the Climos F200, the bypass can be simulated using the "supply air only" mode. If you have a TFT control unit, you can set this via the option "summer ventilation without bypass."

Our heat pump does not have a cooling function.
I had seen the note about "supply air only mode" and rechecked it yesterday. However, it says that when this function is active, the exhaust air room windows must be opened.
I’m not going to open these windows every evening and go to the unit to activate the function.

We didn’t expect noticeable cooling from a ventilation system, but it shouldn’t heat up the house either.

Perhaps the heat recovery is mainly in an unnoticeable range during summer.
We actually wanted to retrofit air conditioning, but this is not allowed for KfW40-standard homes (energy-efficient homes). The heat pump could even be retrofitted with a cooling function, but we were told this would very likely not be approved for our KfW40 bungalow. That didn’t matter to us since the cooling function was too expensive anyway. The issue with air conditioning is more frustrating.

Bierwächter schrieb:

We originally planned to retrofit air conditioning, but with KfW40 standards, this is not allowed.

We also have KfW40, and with the air conditioning, a different calculation method was used, which then worked without any problems. In my experience, energy consultants often have rather limited knowledge, especially in this area. I contacted several energy consultants in my federal state about our planned heating concept, and all of them immediately declared it impossible. In the end, I found an engineering firm that apparently implements various concepts nationwide and has proven to be very competent.