Controlled residential ventilation system - decision support

Hello everyone,

we have decided to build with GÜ and the start of construction is now imminent. We now have to decide on a specific controlled residential ventilation system.

The single-family house has three floors (KG, EG, OG), and the floor area of each floor is about 80 sqm. The controlled residential ventilation is planned only for the EG and OG, not for the basement.

We now have the choice between two controlled residential ventilation systems, the Zehnder Comfoair Q350 and the Wolf CWL-300. The Wolf system would be overall (including pipes, installation, etc.) 1,700 euros cheaper.

As far as I can see, the Comfoair 350 is the newer system, has lower noise emissions and a higher heat recovery rate. In addition, it is naturally designed for 50 m3 higher capacity than the CWL-300, which might affect operation in that it could be run at a lower setting and thus operate quieter and more economically.

Now we have the following considerations: Do the lower measured noise values actually make a difference in real life (or only under laboratory conditions)? How about the sizing of the system: Theoretically, 300 m3 max. capacity would be enough for us, but would 350 m3 not be better for practical reasons? Ultimately, the Comfoair Q350 is certainly the better system, but we are asking ourselves whether the 1,700 euro premium is worthwhile for our house...

Which controlled residential ventilation system would you recommend as experts? It is quite difficult as laypersons to make the right decision here.

Thank you in advance!

Also consider the filter Price and whether there are, for example, expansion options for cooling.

I would take the Wolf. I am also rather an advocate of preferring something bigger rather than too small, especially for the reasons you mention. But I wouldn't pay 1700 more just because of the 50cbm. Is the basement hermetically sealed off from the rest of the house or why is it not ventilated?

Hello everyone,

we have decided to build with GÜ and construction is about to start soon. Now we have to decide on a specific controlled residential ventilation system.

The single-family house has three floors (basement, ground floor, upper floor), and the floor area of each floor is about 80 sqm. The controlled ventilation system is planned only for the ground floor and upper floor, not for the basement.

We now have the choice between two controlled ventilation systems, the Zehnder Comfoair Q350 and the Wolf CWL-300. The Wolf system would be 1,700 euros cheaper overall (including pipes, installation, etc.).

As far as I can see, the Comfoair 350 is the newer system, has lower noise levels, and a higher heat recovery rate. In addition, it is dimensioned about 50 m3 higher than the CWL-300, which might mean in regular operation it could run at a lower setting, thus operating quieter and more economically.

We now have the following considerations: Do the lower measured noise values even make a difference in real life (or only under laboratory conditions)? How about the sizing of the system: Theoretically, 300 m3 max. performance would be enough for us, but wouldn’t 350 m3 be better for practical reasons? Ultimately, the Comfoair Q350 is certainly the better system, but we wonder if the 1,700 euro extra cost is worth it for our house...

As experts, which controlled ventilation system would you recommend? As laypeople, it's pretty difficult for us to make the right decision.

Thanks in advance!

We also have basement, ground floor, and upper floor with 85 sqm and the Zehnder Q350. But I can’t provide any experience yet. I can’t say anything about the second system. Have you already had everything calculated and planned?

Why didn’t you include the basement? Is it unheated?

Mycraft: Ok, but what about the noise development of the Wolf? According to measurements for exhaust air, the Comfoair produces 39 dB(A) at 273m3 capacity, whereas the Wolf already produces 59 dB(A) at only 235 m3 capacity. I don't know if you can actually notice the difference in practice, but the measured values alone differ quite significantly.

The basement is mostly storage (except for an occasionally used office/guest room). We have also considered including the basement, but then we would have to size the system larger. The finished room is heated, the rest is not.

What do you think, what additional costs would be reasonable if the basement (84sqm floor area, including one finished living space) is included in the ventilation concept after all?

What exactly is the difference between the equipment. The devices themselves are all quite similar in price. Mostly it is the accessories that are more expensive. I think the fans and silencers will be qualitatively different. The Zehnter should also be enough for your basement. It is enough for us. The question is only about the cables and pipes as well as working hours. But we did not have any offer without basement.