ᐅ Is Moisture Recovery Useful in Controlled Residential Ventilation?

Hello everyone,

Does moisture recovery in a mechanical ventilation system with heat recovery make sense? I have read different opinions on this. Without moisture recovery, the air can be too dry in winter, especially for allergy sufferers. On the other hand, some say that in timber frame houses, it is better to keep the moisture outside and that the additional cost for moisture recovery can be avoided.

What is your opinion on this? Thank you

Whether wood or stone... in winter, humidity drops to around 30% with controlled mechanical ventilation.

If you can live with that, then you can use controlled mechanical ventilation without humidity recovery. However, if my system back then had included humidity recovery, I would have definitely chosen it.

When choosing a mechanical ventilation system with heat recovery, I was advised to start with a standard heat exchanger (mainly to remove construction moisture). If the air gets too dry in winter, I can still retrofit a humidity recovery unit later. If I keep it installed all year, it would also recover very humid air in summer, which I actually want to avoid.

That doesn’t make sense... retrofitting is more of an emergency solution and shouldn’t be the standard approach... most systems cannot be retrofitted anyway, which means your options are basically limited to just a few models... and the price for a heat exchanger with moisture recovery is roughly half the cost of the entire unit.

In summer, it doesn’t really matter what type of heat exchanger you have installed... the air won’t become more humid than it already is, nor significantly drier... because moisture absorption is limited.

In winter, on the other hand, these systems tend to dry out homes simply due to the large temperature difference between inside and outside, to put it simply... it’s a complex topic, but unfortunately you were given incorrect information...

I discussed the topic of humidity with a building services engineer – a Visionair controlled residential ventilation system was planned. He said that having damp flower pots is enough to maintain humidity levels. Are there any experiences with this? Could someone please share their insights if they operate a controlled residential ventilation system without moisture recovery?

merlin83 schrieb:
I brought up the topic of humidity with a building services engineer – a Visionair controlled mechanical ventilation system was planned. He said that moist flower pots are enough to maintain the humidity. Are there any experiences with that? Maybe someone who operates a controlled mechanical ventilation system without humidity recovery could share their experience?

We don’t have any moist flower pots (and I don’t think they really help), but we do have a controlled mechanical ventilation system without humidity recovery.

The dry air doesn’t bother us – humidity problems in the house are unimaginable with the controlled mechanical ventilation. BUT in winter, the humidity is only about 30% (+/-), which might be uncomfortable for some people (e.g., dry eyes, coughing, etc.). Even lots of cooking only helps for a very short time. The ventilation system runs at level 3 out of 8.