Split air conditioning and controlled ventilation with heat recovery

Hello everyone.

Does anyone have experience with a split air conditioner in combination with a central controlled residential ventilation system with heat recovery?

The basic question is whether the controlled residential ventilation can distribute the cold air from the air conditioner and how well or poorly that works.

My idea: Due to simplicity and short distances, I am considering a split air conditioner with 2 indoor units.
The outdoor unit would be placed on the garage and from there it is only about 50 cm through the wall into the bedroom upstairs and living room downstairs. Power supply is also available. I do not want to put in a lot of effort or lay long lines to actively cool all rooms. The children’s rooms are not so easy to reach. It would work via an external duct on the house wall, but for aesthetic reasons I do not want that.

The house was built in 2018 and exceeds the KfW 55 standard.
The primary energy demand is calculated at 42 kWh/m² and the values from recent years confirm this.
We have 178 m² of living space according to the Living Space Ordinance and about 212 m² of floor space. No basement and a gable roof. Hence the discrepancy.
A brine-water heat pump is used for heating, which is also equipped with a cooling function.
Cooling via underfloor heating works satisfactorily and keeps the temperature at about 24 degrees even in midsummer.
However, you have to consistently shade and follow the recommendations. Once the heat is inside, it takes several days for the cooling to lower the temperature again.
In 2022, we used 2169 kWh of electricity and generated 9408 kWh of heat for heating and hot water.
The building is therefore comparatively efficient when it comes to insulation.

We still want to get advice on the air conditioner. Both rooms are about 40 m² and the question arises whether to choose a more powerful air conditioner to have more cold air to distribute?

The controlled residential ventilation helps with this to some extent as well. In summer, it cools the outside air by a good 8 degrees.
The airflow rate is about 180 m³ of air per hour in the auto setting.

Would the controlled residential ventilation noticeably distribute the cold air from the air conditioner and cool the other rooms, or would we rather get climate zones in the house?

Thank you very much in advance.

No one has any experience? No one who has an air conditioning system and a [Kontrollierte-Wohnraumlüftung]?

A controlled residential ventilation does not distribute really well. The heat transfer is quite low. However, I do think that the temperatures will largely equalize, as with the heating as well. Because the house is only insulated on the outside and not between rooms.

A controlled residential ventilation system does not distribute heat very well. The heat transfer is quite low.
However, I do think that the temperatures will largely equalize, as with heating as well.
Because the house is only insulated on the outside and not between rooms.

If you heat only the ground floor with a wood stove, almost nothing reaches the upper floor. It will probably be no different with an air conditioner, even if the positive effect here is that heat only rises.

The controlled residential ventilation system helps very little with that. In the end, you need at least one air conditioning unit per floor.

If you heat with a wood stove only on the ground floor, almost nothing reaches the upper floor. It’s probably no different with an air conditioner, even though the positive effect here applies that heat only rises upward.

The controlled residential ventilation helps very little with that. In the end, you need at least one air conditioning unit per floor.

One air conditioning unit is planned per floor.
I will report back.

Controlled residential ventilation doesn't actually distribute air. It extracts air and blows in new air. Therefore, when cooling is running, the controlled residential ventilation should ideally be turned off or run only on a low setting.