Controlled residential ventilation - Does the smell spread throughout the house?

Hello,

I was at my brother-in-law's yesterday, who built in 2007, with controlled residential ventilation and an air-to-water heat pump. All combined in the LWZ 303 unit from Stiebel Eltron.

No matter where you are in the house, dust can be found everywhere (e.g. on the wardrobe). If you pick it up with a finger and smell it (don’t sniff), it always smells like detergent. The room itself does not smell like that. Except for the utility room/HAS. Where the washing machine and the LWZ are in the same room. According to him, it sometimes also smells like his wife’s hairspray, but I couldn’t verify that.

From what I have researched, the heat exchanger in the LWZ is a cross-counterflow heat exchanger. As I understand it, supply and exhaust air are hermetically separated from each other, so no odors can transfer.

However, my brother-in-law is quite sure that the airflows directly touch each other. After some research, I came across so-called regenerative systems, which are rather used in decentralized ventilation and alternately blow or suck supply air and exhaust air through the same device in synchrony.

One suspicion of mine was whether the intake might be leaky and also be drawing air from the utility room?

Another suspicion now is whether odors from washing might be escaping through the air duct to the outside and being drawn back in directly. That would mean the air duct is leaky?

What does this sound like to you?

After a planning error.

The point is that the odors from these rooms like bathroom or laundry room are extracted. If they are then actually sucked back in outside, it is a air short-circuit = planning error.

If I find dust in the wardrobe and it smells like detergent, I would consider whether I used too much detergent... the smell doesn't seem to be in the air. Why is your brother-in-law sure that the air currents touch? That would be rather unusual.