ᐅ Is a ventilation system cost-effective? Does it save money?

nordanney schrieb:

Living in the countryside, I can confirm this. There is much less dust inside—otherwise, you do notice when the tractors are out in the fields and/or when straw and hay are being harvested.

That means you have to keep all windows and doors closed during summer. That would be unimaginable for us.

LarsBr80 schrieb:

Thanks for all the answers. I already suspected that the payback period of 10 years was quite overestimated. But if the craftsman meant the cleanliness and dust buildup in my lungs, he’s probably right. So it seems the investment does pay off financially to some extent over time, and there are additional positive side effects that can’t really be quantified. So why doesn’t everyone do it? Sounds like a great investment...

Because there are people (like us) who love to keep windows and doors open as soon as the weather allows. Because it expands living space, creates openness and freedom. Who love sleeping with an open window—not only for the fresh air but also for birdsong and other natural sounds, like the croaking of frogs in our pond.
Because it requires upfront money (either savings or financing) and space. Because it probably would never pay off financially for people like us.
Because it can sometimes cause air that is too dry.

motorradsilke schrieb:

That means you would always have to keep all windows and doors closed in the summer. That is unimaginable for us.

Of course, plenty of fresh air enters the house in summer—through the ventilation system. Why would I need to keep all windows and doors open? There is no (rational) reason for that. If you feel better with open doors and windows, then do so.

motorradsilke schrieb:

but also because of the birds and other natural sounds, for example, the croaking of frogs in our pond.

Even more reason to have a ventilation system. Who seriously wants to listen to croaking frogs all night because you can’t fall asleep? Unfortunately, that’s the usual case.

motorradsilke schrieb:

Because it costs money to install

Yes.

motorradsilke schrieb:

It takes up space

Not really, especially not decentralized systems.

motorradsilke schrieb:

Because it probably would never pay off for people like us

It barely does for new builds anyway.

motorradsilke schrieb:

Because it can partly cause air that is too dry.

That depends on the specific model. But even without a system, it’s not much different—the laws of physics can’t be bypassed.

But as I said, it’s an individual choice. Favoring open windows is emotional. Favoring controlled mechanical ventilation is a rational choice with many advantages.

nordanney schrieb:

Of course, in summer a lot of air enters the house through the ventilation system. So why should I have all the windows and doors open? There is no (rational) reason for that. If you feel better with open doors and windows, then go ahead.

Another reason to have a ventilation system. Who really wants to listen to croaking frogs all night because they can’t fall asleep—that’s unfortunately quite common.

Not really, especially not decentralized systems.

They hardly come into play at all with new builds.

It depends on the specific model. But it’s not much different than without a system—the laws of physics can’t be bypassed.

But as I said, it’s individual. Favoring open windows is emotional. Favoring controlled ventilation is rational, with many advantages.

The comfort factor should be quite important in a house, at least for us. Many decisions when building a house are not rational but based on personal comfort. For example, a shower is more practical than a bathtub for rational reasons.

Right now, I’m sitting in the living room with the patio door open (it’s still too cold outside), listening to the birds and the sound of the waterfall in the pond. I wouldn’t want to miss that.

By the way, the pond is far enough from the bedroom, so we can sleep well despite the frogs. But of course, that is subjective.

Decentralized ventilation systems have already been essentially ruled out as not very effective for new builds. And a central ventilation system requires about 1 m² (10.8 sq ft) of space.

And no, when you ventilate by opening windows, you only bring in dry air temporarily, but with a ventilation system it is continuous. That’s why dry air can be more of an issue with a system.

You can reduce the problem of dry air with ventilation systems that have enthalpy heat exchangers.
Opening windows is also possible when you have a ventilation system.
In our home, windows and doors are open despite having a ventilation system—when we want to, not because we have to.
Who ventilates manually enough during winter anyway? Especially for those sensitive to the cold, even in old houses, you often notice it’s time to air out. At least twice a day for 5 to 10 minutes of quick airing by fully opening windows, not just leaving the guest bathroom window tilted; if you’re at home, even more often—which very few people actually do.

I also love hearing birdsong from bed in the morning, and when the church bells ring loudly, it’s time to get up quickly. In our bedroom, the window is tilted or open despite having a ventilation system—unless a party is going on at a neighbor’s three houses away.

nordanney schrieb:

But as I said, it is individual. For open windows, the argument is emotional. For controlled ventilation systems, the argument is rational with many advantages.

This interpretation of “rational” is completely detached from real life. By that logic, it would be rational not to have children, since from a rational perspective they have measurable disadvantages: they require huge amounts of time and money, create mess, and reduce air quality. Totally inefficient.

What is rational is measured by achieving the desired goals. Different goals sometimes require different solutions.

It is rational, when designing and building your own house, to do so in a way that best supports your own life priorities. Different technologies can be effective for this. Framework conditions must be taken into account.

haydee schrieb:

You can reduce the problem of dry air with ventilation systems that use enthalpy heat exchangers.
Opening windows is still possible when you have a ventilation system.
Here, we often keep windows and doors open despite having a ventilation system—when we want to, but it’s not mandatory.
Who ventilates manually enough, especially in winter? Even in old houses, those sensitive to the cold often notice it’s time to air the rooms. At least twice a day for 5-10 minutes with intensive ventilation, not just leaving the bathroom window tilted when you’re at home—most people rarely do this.

And I also love hearing the birds chirping in the morning while still in bed, and when the church bell rings loudly, it’s a clear signal to get up quickly. Here, despite the ventilation system, the bedroom window is tilted or open—unless there’s a party going on three houses down.

Sure, but the heat exchanger is an additional cost.
In our almost four years of experience, we’ve developed a good routine for ventilation: in the morning, open the shutters, windows for a few minutes, then close them again. In the evening, the reverse. During the day, we open doors frequently anyway (cat going in and out, walking the dog, going to the garage, trash area, shed, leaving...) so this is completely sufficient, maybe not in theory, but in practice.
I’m not against controlled mechanical ventilation. The question was just why people build houses without it.