ᐅ Is a Central Ventilation System Really Necessary?

The topic is highly charged emotionally. If you ask three homeowners, you’ll get five opinions.

So here is my view:
It’s not necessary. We use humidity-controlled supply air units (from aereco) and exhaust ventilation in the upstairs bathroom and the guest toilet on the ground floor. And no, in winter you won’t be sitting in cold drafts wearing a scarf and jacket. Our architect has been installing these for many years. So far, there have been no complaints from residents. No mold either. The initial investment costs are much lower than a balanced mechanical ventilation system with supply and exhaust ducts in every room. The ongoing costs (heating the cold incoming air with the described solution versus electricity, maintenance, and filters for a balanced mechanical ventilation system) will probably balance out.

klblb schrieb:
And no, in winter you will not be sitting in cold drafts wearing a scarf and jacket.

Unfortunately, that’s not the case... unless you are not sensitive to cold, consider 20°C (68°F) indoors as warm, or have enough money to keep the heating running constantly...

Hello,

Mycraft schrieb:
Your architect has no clue...

On the contrary, the architect finally seems to be someone with practical experience!

Katha28 schrieb:
We visited the energy consultant, and he strongly recommended a central ventilation system for our house (which will only be built starting next spring) because of mold issues. Our potential architect says that this is not absolutely necessary, and that ventilation in the bathroom and kitchen would be sufficient.....

For clarification: Your energy consultant recommends the central system because it makes it easier for him to provide the required documentation. Your architect is correct, as in reality—if at all—heat recovery only makes sense in the wet rooms and kitchen.

Whether central or decentralized systems are better is a matter of debate—I would always recommend choosing one option, especially if you cannot ensure multiple airings within the first two years. And don’t let anyone convince you that you will have drafts if you go with a decentralized system. We have been installing these occasionally for many years, and no customer has experienced constant colds or joint pain since.

Best regards, Bauexperte

[A central ventilation system is not only expensive but also somewhat complicated to install and difficult to clean. Over the years, it is likely to become very dirty and may develop an unpleasant odor.]

So these statements from the architect are simply nonsense... assuming the house is intended to meet today’s standards...

Hello,

Mycraft schrieb:
"A central ventilation system is not only expensive but also somewhat complicated to install and hard to clean; over the years, it will likely become very dirty and may start to smell."

The architect probably didn’t say exactly that, even though there is some truth to it.

Mycraft schrieb:

So these statements from the architect are simply nonsense... assuming the house is built to today’s standards...

I have told you several times already—a central system seems to be exactly the right choice for you. That doesn’t mean it has to be the best option for others, or that a decentralized system is worse, nor that a central system is free from potential issues.

You should visit some construction sites and see how some central systems are installed, what kind of residues you find on the plastic ducts, how quickly the screed spreads its silent layers, and so on. Then you will get a realistic picture. The idea that a system can also start to smell is not far-fetched either… in the first years, cleaning intervals are still maintained, then they gradually become less frequent until the system—quite often—is completely neglected.

Ultimately, it’s always a question of budget; there is no clearly better or worse system, just more or less comfort.

Best regards, Bauexperte

Bauexperte schrieb:
....To clarify: Your energy consultant recommends the central system because it makes it easier for them to provide proof later on....

Proof can be just as easily provided with a decentralized solution.

Bauexperte schrieb:
..., to decide on one option if you cannot ensure multiple ventilations in the first two years....

For construction drying, you don’t need to install an expensive controlled mechanical ventilation system!
Modern buildings are very well insulated, meaning the indoor air humidity levels are correspondingly high. This leaves little chance for mold to develop.
Decentralized controlled mechanical ventilation can be described as “half-baked.” It is often inefficient, frequently causes noise issues and/or condensation. Whether you really want such a device in the bedroom is definitely something to consider.

Best regards