ᐅ Centralized vs. decentralized ventilation systems

Hello everyone,

We are currently planning the construction of our single-family home and are considering whether to install a decentralized or centralized ventilation system. According to a preliminary quote from a general contractor, there is a cost difference of about 8,500 euros (cost for decentralized) versus about 13,000 euros (cost for centralized), which I had expected to be higher. We are currently living in an apartment with a decentralized ventilation system and are dissatisfied with it. Mainly, we are bothered by the noise of the fans themselves and the external noises that come through because of that.

Therefore, I wanted to ask you which option you chose. Are you satisfied with it? Would you choose the same again?

Choose a central system. We have just made this decision ourselves. I know two people with central systems and two with decentralized ones. The noise is definitely annoying with at least one decentralized system. I always felt that decentralized systems provide better ventilation.

Just try using the search function. ;-)

In my opinion, decentralized systems are used mainly to fulfill some standards just for the sake of it or because it’s not possible to do otherwise with existing buildings. In new construction, it should always be centralized without exception. Just make sure that it is planned and designed properly, and that an enthalpy exchanger is installed or can be replaced.

At the time, we had some reservations about central systems (expensive central unit, pipes that are inaccessible afterward), and since the general contractor praised the Inventer fans so highly, we chose a decentralized system. It’s acceptable, but I wouldn’t do it again. The lower settings are inaudible during the day, but the nominal ventilation rate of 0.4 air changes per hour is only reached at about 60% power. I find setting 3 (50%) still fine during the day; it usually runs at setting 2 (33%, about 5 air changes per day). At night, we pause the fans upstairs for 8 hours.

The problem is less the noise while the fan is running and more that it always cycles off after a minute, pauses briefly, then starts again. When you're lying in bed and have trouble falling asleep, that is really annoying. In terms of noise insulation, I think the oscillating fans are acceptable, but the exhaust fans in the bathroom are not good. On the west side, we also have the problem during strong winds that gusts push air into the fan. Since installing the hood, it’s better, but you can still hear it. There are special wind inserts for this, but of course, they cost extra.

RotorMotor schrieb:
In my opinion, decentralized ventilation is used mainly just to meet certain standards superficially or because it’s not possible otherwise in existing buildings. In new construction, it’s always central, no ifs or buts. (...)

You clearly don’t know much about this. You don’t need to keep showing it.

With decentralized ventilation, I can control each room individually if I want, or at least separate the upper floor and ground floor. For example, at night I set the downstairs to level 2 or 3. Nobody is disturbed. In the morning and evening, when everyone is in the living room, I set the upper floor to level 3. Nobody is disturbed.

A central mechanical ventilation with heat recovery (MVHR) system doesn’t allow room-by-room control, at least not at the price normally charged for single-family homes.

And if a fan breaks, I just replace it. Costs about 500 EUR (approximately 530 USD) including the heat exchanger. How much does the central fan for an MVHR system cost? 😉

Oh, and you also save on ventilation ducts running through the entire house. They don’t stay clean forever either…

WilderSueden schrieb:

At the time, we had some reservations about central systems (expensive central unit, ducts that you can never access again), and because the general contractor was so enthusiastic about inverter fans, we opted for a decentralized system. It’s fine, but I wouldn’t do it again. The lower settings are silent during the day, but the rated ventilation rate of 0.4 air changes per hour is only reached at about 60% power. I find level 3 (50%) acceptable during the day; usually, it runs at level 2 (33%, around 5 air changes per day). At night, we set it to an 8-hour break on the upper floor.

The problem is less the sound while the fan is running and more that it always cycles off after one minute, pauses briefly, then turns on again. When you’re lying in bed and can’t fall asleep easily, that’s really annoying. Regarding noise protection, I find the oscillating fans acceptable, but the bathroom exhaust isn’t great. On the west side, when there are strong winds, we always have the problem of gusts pushing back into the fan. Since installing the hood, it’s better, but you can still hear it. There are special wind inserts for that, but those cost extra.

Yes. Sensitive individuals might have trouble with this. We ran the fans at 100% for the first few weeks after moving in, and everyone slept well.

The ducts you can never access again can become a major issue.
Think about it. If you have mold in a room... where does it go? And how do you remove it completely from the ducts?