Building a single-family house in NRW

Hi,

Why not? It's a controlled residential ventilation system with heat recovery, right?

Sure, with heat recovery.

But:

50 watts running 24/7 amounts to about 110 euros in electricity costs per year. Plus the cost for changing filters twice, we're easily at 200 € per year.

Plus financing costs of 100-150 € per year (financing around 10,000 euros at 1-1.5%).

So costs of about 300-350 € per year.

Estimated heating demand (derived from the old house, which was less well insulated) around 15,000 kWh. These currently cost about 600-700 €.

The controlled residential ventilation would have to cut heating costs in half to be economical, and it never does that!

Regards,

Andreas

My question about the costs only referred to the matter of energy efficiency, not so much to the investment costs. With 50W/h we are at 1.2kWh/day. And with 1.2kWh I can exchange the entire air in my house twice at 0°C AT, and that completely without [Wärmerückgewinnung] through the windows.

Hi,

exchange the entire air 2x at 0°C AT,

We have about 670 m^3 to ventilate and exchange the air every 3 hours, so 8 times a day.

Best regards,

Andreas

... but the horror scenarios here are absolutely far-fetched.

You do have ventilation with the window frame ventilator, so you don’t need to ventilate manually.
Just seal them all airtight and validate your statement that the sensors only go off after showering.
If that’s the case, I’ll believe you too.

Why should one do that? Such an investigation is only done when needed, which I don’t see here.

I can’t see germs and certainly not what happens inside the pipes.
And that is exactly a major argument of the opponents. Everyone philosophizes about possible germs but no one has ever proven it. It would be really great information for future generations.

No one disputes that a controlled residential ventilation system is not economical.

However, we all agree that ventilation is necessary, no matter how?! And if one says manual ventilation is enough, then one must also be honest with oneself and do it properly, or get a notification via sensors—I even find being notified via app quite practical.

With 50W/h we have 1.2kWh/day. And with 1.2kWh can

However, this does not take into account the aspect that, for example, a Zehnder with heat recovery has an ηWRG,eff of 84%.

If you ventilate, the 1.2kWh is simply lost. Thanks to heat recovery, it is not. This aspect should not be overlooked.

Between 10-20% energy losses that a normal house has typically arise from classic ventilation.

We have about 670 m^3 to ventilate and exchange the air every 3 hours, so 8 times a day.

I have to say that at first we didn’t want the controlled residential ventilation and only included it because we could completely do without windows in two basement rooms and also save the solar thermal system on the roof. This almost completely offset the cost of our controlled residential ventilation, since I only purchased the materials and installed the system myself. It’s not a big deal.

It has only been in operation for a few weeks now and I am surprised myself how pleasant it is. Pleasant air and comfortable humidity everywhere. No windows that I forget to close after airing out. And also significantly less campfire/fireplace smell in the house than with open windows.

We had already lived in the house for almost 3 months before I finally got the ventilation running. It was quite a bit of effort to keep the humidity in the house below 50%, especially in rooms where no ventilation/cross-ventilation was possible. And always these discussions: “There’s a draft, the child will get sick, etc...”

Annoying!

Now with controlled residential ventilation we have a constant humidity of between 40 and 45% throughout the entire house without opening a window.

We now see the controlled residential ventilation as a pleasant “background ventilation.” After showering or cooking marathons, a window is still opened. But much shorter and less often than before.

Best regards,

Andreas