Controlled residential ventilation or photovoltaic system? Seeking decision support, pros and cons

New houses are indeed designed and built with decentralized fans.

Each variant has its advantages and disadvantages, and everyone has to weigh what fits best for them. One person finds full automation great, another prefers to have as much control and options as possible.

Mold formation is definitely an issue in modern airtight houses, but it is important to know which variants exist when making a decision. Besides decentralized devices, there are other ventilation concepts that do not require complete piping throughout the entire house: For example, the option to install exhaust air in the kitchen and bathroom(s) and provide fresh air supply in the other rooms (without a fan). This is then a so-called exhaust air system, a third variant practically alongside central ventilation and decentralized ventilation. In any case, I recommend everyone to inform themselves thoroughly and weigh the options before installation.

To come back to the original question: Regardless of the form, I would prefer ventilation over photovoltaics.

Hello everyone,

thank you very much for all the opinions.
And sometimes a decision just has to be made without thinking for days or weeks.
I previously commissioned my plumber for a controlled residential ventilation system. It will be a Zehnder Comfoair Q450 enthalpy. Cost around €14,000. Since the decentralized fans are omitted, an "additional cost" of around €11,000.

For me, there is even another big gain in comfort:
Thanks to the controlled residential ventilation, I can run my Bora system as a recirculation instead of an exhaust system and don’t always have to keep a window open while cooking.

Regards
gnom

From my side, thank you for the info (I always find it good when a decision is made at the end of discussions (ideally followed by a report of experience later )).

Best regards

For me, there is even another great convenience gain: Thanks to the controlled residential ventilation, I can operate my Bora system as a recirculation instead of an exhaust system and don't always have to keep a window open while cooking. Regards, the gnome

I don't quite understand the context now. What would have stopped you from using a recirculation extractor hood without controlled residential ventilation? Opening windows with an exhaust extractor hood is initially only necessary if a room air-dependent combustion appliance (gas boiler or wood stove) is in use. This serves pressure equalization and is meant to prevent exhaust gases from being drawn into the living space.

If you have a heat pump and no chimney, opening windows is initially not necessary. Only proper operation of the exhaust extractor hood makes this necessary.

However, this only has a secondary connection to controlled residential ventilation. With controlled residential ventilation, an open window or wall vent is recommended with an exhaust extractor hood in order not to shift the pressure relationship between inside and outside and to ensure the proper operation of the controlled residential ventilation. But only for the time the extractor hood is on.

Apart from that, your decision in favor of controlled residential ventilation is absolutely right. We installed the Zehnder Q350. I would definitely recommend getting the version with the enthalpy exchanger. It costs 500-1000€ more but brings enormous benefits for the indoor climate, as you don't constantly have the typical problems with overly dry air.

If necessary, this could also be easily retrofitted on the device.

The Zehnder Q450 is a very good choice

Opening windows with a ducted exhaust hood is initially only necessary when a room air-dependent combustion appliance (gas boiler or wood stove) is used.

In new buildings, exhaust hoods are always tricky because of the building's airtightness. Such an exhaust hood can really push a lot of air outside; where is the air supposed to flow in from? A chimney would of course be really bad, but even without one, this remains a problem.

But yes, I still don’t understand why this is less of a problem with controlled residential ventilation. Controlled residential ventilation is not a replacement for an exhaust hood (but it helps with odors).