ᐅ Decentralized Mechanical Ventilation with Heat Recovery + Wood-Burning Stove

Hello forum,

I am currently planning the upcoming renovation of our purchased house (solid bungalow, 120m² (1,292 sq ft), fully basement, built in 1975).

Planned renovations:
- Windows + roller shutters + front door
- Exterior insulation + ceiling insulation of the top floor ceiling
- Gas condensing boiler with solar support
- Wood-burning stove

Since I have read quite a bit about decentralized controlled residential ventilation with heat recovery, I am wondering if it is possible (and practical) to integrate this system. Energetically, it might not bring much advantage, but it should significantly increase comfort and especially improve the indoor air quality (keyword: fear of mold).

So far, the plan was:
- Wood stove without separate combustion air supply
- Exhaust range hood with negative pressure monitor (window contact switch is not an option for us)

My questions regarding the combination with decentralized controlled ventilation:
1. Is an exhaust-only range hood possible?
2. If not, when using a recirculating range hood + controlled ventilation, is a negative pressure monitor required?
3. Does the wood stove need to be room-air independent with its own fresh air supply?
4. Is the controlled ventilation system installed only in bedrooms (as I have read), or also in bathroom and kitchen?

So many questions...
Maybe one of you has experience with a similar setup. I would appreciate hearing about your experiences.

Regards

Gebuesch

Hello Gebuesch, regarding question 1: in principle, an exhaust hood is possible, but from a ventilation perspective it is not practical. These systems operate with an air volume of 300-700 m³/h (176-412 CFM). First, this wastes heating energy, and second, where will the replacement air come from? It is better to use a recirculating hood combined with an exhaust fan that only moves about 80 m³/h (47 CFM). Question 2: with a recirculating hood in combination with a controlled mechanical ventilation system, a pressure monitor is not required, only with a pure exhaust hood. However, if you install a wood stove, a pressure monitor is always needed to shut down the system in case of negative pressure (this is required by the chimney inspector). Question 3: the wood stove should ideally have a combustion air supply independent from the room air. Question 4: the decentralized controlled mechanical ventilation system is installed in all living spaces such as the living room, children’s and bedrooms, as well as offices, etc. Moisture-controlled exhaust should be installed in the bathroom and possibly in the guest toilet and kitchen (see question 1). Regards, HIGIL

1. A range hood is possible, but only with a window sensor. Unfortunately, this conflicts with the concept of controlled ventilation. The same applies to leaving windows open at night.
2. With recirculation, you don’t need a pressure sensor.
3. The stove should be room-air independent; otherwise, the same rules apply as with the exhaust hood. Whether you need a pressure sensor depends on the ventilation system itself and the installed stove. We have a Zehnder system and an Olsberg stove and don’t require a pressure sensor. There is a building code approval. However, since we open a window slightly when the stove is operating to prevent the living area from overheating, it doesn’t really matter.
4. The biggest advantage is that the humid air from wet rooms (boiler room, laundry room, kitchen, and bathrooms) is expelled from the house. Therefore, exhaust vents should be installed there, and supply vents in the living areas.