ᐅ Controlled residential ventilation with decentralized fresh air supply!?

Hello forum,

My original plans for my single-family house included a mechanical ventilation system with heat recovery and central supply and exhaust air.

However, a plumber has now recommended a different system:

Central exhaust with heat recovery through the ground-source heat pump (though I still prefer a gas boiler for now) and decentralized supply air through openings in the roller shutter box.

My concern is that the unheated supply air could be very uncomfortable in winter, especially in the bedroom.

The advantages mentioned for this system were the price, no sound transmission between rooms via the supply air ducts, and hygiene (no contamination of the supply air through ductwork).

I think the hygiene argument is nonsense.

What are your overall thoughts on this? Especially regarding the comfort impact of cold supply air?

Hello,

FWIng schrieb:
...My concern is, however, that the unheated supply air in winter could be very uncomfortable. (Especially in the bedroom)

The concern is quite justified. With centrally preheated supply air through heat recovery, the supply air temperature is only a few Kelvin below the room temperature and depending on the planned (required) air volume, it is hardly noticeable.
-15°C (5°F) directly from outside is definitely more noticeable ;-)

Best regards

A few degrees below room air temperature would probably still be desirable – especially when I think of an otherwise airtight sealed bedroom, with heat input from two people and a waterbed.

Only very cold drafts from the decentralized ventilation would then have the "comfort" of a tilted window... and avoiding exactly that was actually one of the reasons in favor of controlled residential ventilation for us.