Is controlled residential ventilation in this case sensible or not?

Hello construction expert,

...If it stays within the minimum range (i.e., max. 3 panels), then yes; otherwise rather not.

Why?

...I do not have to calculate it myself, for that I commission external experts with whom I collaborate, who, however – as you have unfortunately often demonstrated – seem dubious to you.

Apparently not without reason, since no solution to the OP's problem was presented, only a manufacturer was criticized.

..., you still suspect advertising.

It would be quite easy to refute such "suspicions."

... It repeatedly shines through that you trust no one except yourself.

Completely correct, as long as counter-arguments are solely based on advertising.
Therefore, I fundamentally advise every builder to be critical before deciding on rather high investments based on questionable glossed-over calculations.

... What you should reconsider, however, is your unpleasant manner of increasingly discrediting me and reducing me to a brochure regurgitator. That is not only bad style, it is simply injurious to honor.

Apparently, you find an interlocutor unpleasant especially when your own position falters due to lack of technical arguments.
Certainly, I sometimes provoke, but insulting anyone's honor is not intended and should not be understood as such.

Likewise, Merry Christmas

nana Christmas, so love :)

I think, as always, there is more than one truth. And maybe the calculated difference in reality is smaller than one assumes beforehand.

We also have a gas boiler + solar thermal system (6 sqm) and did not negotiate on that, because you can't insulate every house on the walls anymore. Lower U-value would be 0.
In the end, it also depends on user behavior. Someone who only washes their hands with warm water will certainly not use the solar thermal system as much as they could. But my wife is a water baby who takes long warm baths and does not just let the water run once. I like to shower for a long time. And my son is slowly starting to enjoy longer splashing around. We are aware that all this is not efficient and offers savings potential. The fact is, the system saves us real money. And since in our case we had no additional costs (certainly these were somehow calculated in the base price) and we also get 2,500 from the Kfw because of it, it fits well.

The only negative aspect I could see in a solar thermal system: technical equipment that can break down, and maybe there is no space left then for a photovoltaic system.

Surely this is only the opinion of a construction layperson who nevertheless feels well advised. Calculation tricks aside. I'm sure we could have done many things better, but at some point, as a builder, you are overwhelmed. Experts constantly talk at you, and you no longer know who is right. It's like in my profession... java or c++ ... pure matter of faith, which can certainly also be bombarded with facts.

... you’re still suspecting advertising.

This seems to be a kind of witch hunt here in the forum.
Like in the Middle Ages.
Whoever accuses others of advertising gets burned... I mean deleted, regardless of whether it’s true or not.
Except if it’s the Inquisition itself, which, of course, stands above it... Compliance at its best.

We have also consciously decided against solar. Our consumption is so low that payback is only possible very late.
Either the energy price has to rise significantly again, or the efficiency of solar systems must become significantly higher, then it pays off again.
But in the end, it’s also a matter of opinion. Some people try to think ecologically for themselves and accept the additional costs.

If you naturally ask a solar salesperson whether solar or not, the answer shouldn’t surprise you.

Hoping that my post will not be deleted by the Inquisition, pardon, the administration, I remain

with Christmas greetings

Hello,

This seems to be a kind of witch hunt here in the forum. Like in the Middle Ages.

not only here, enlighteners are mostly witches and are persecuted by the inquisition, since one questions the profit interests of some ;-)

I actually didn’t want to, but since Bauexperte demands very concrete examples, I rummaged through my documents again:

Example 1:
Construction project near Dortmund, year of construction 2008, KfW 40 according to the definition at that time, high-end provider:
- Hot water demand according to proof => 2544 kWh/a, theoretical solar thermal system coverage rate 62%
The system should have delivered 1577 kWh/a accordingly.
Results of subsequent yield measurements using a heat meter: 83.5 kWh (5.3%) !!!!

Example 2:
Construction project near Berlin, year of construction 2010, KfW 55
- Hot water demand according to proof => 2315 kWh/a, theoretical solar thermal system coverage rate 60%.
The system should have delivered 1388 kWh/a.
Results of subsequent yield measurements using a heat meter: 167 kWh/a (12%) !!!
This could be continued indefinitely.

One could also choose another title:Beware of swindlers, con men, and charlatans.

...We also consciously decided against solar. Our consumption is so low that amortization is only possible very late.

Completely the right decision, because the actual energy demand for hot water has absolutely nothing to do with the definition according to the Energy Saving Ordinance/KfW.
In addition, the actual utilization rate! (not efficiency), is significantly worse than generally assumed.

...But ultimately it’s also a matter of opinion. Some try to think ecologically for themselves and accept the additional costs.

Correct, fundamentally every kWh of fossil energy saved is valuable.
However, the vast majority of builders initially assume an overall economical solution for themselves.
Sometimes the green interest is only discovered afterwards, when nothing can be changed retrospectively about the actually existing shortcomings. ;-)
That is of course also known by the sellers, because after completion of a construction project the builder's wallet is usually empty.
Often the possibilities to assert one’s own rights are then missing, not to mention whether it was even noticed that one was taken for a ride.
Prevention is always cheaper than subsequent attempts at cure.

...If you naturally ask a solar seller whether solar or not, the answer should not surprise you.

Also correct, if you let yourself be advised by systemically biased sellers, objectivity regarding an overall economical solution for the builder is rather an alien word ;-)
On the other hand, this is quite legitimate, because those who don’t inform themselves in time rather fill the wallet of others than protect their own. ;-) This certainly also benefits the general public, e.g. in the form of financed VAT. ;-) Unfortunately mostly without an equivalent direct benefit for the individual builder.

Best regards

...Even if the stuff gets through the service life without hail damage or other damage (which according to the manufacturers hardly ever happens), the efficiency of the cells steadily decreases.

Do not confuse photovoltaics with solar thermal systems! These are two completely different things. Especially the storage of thermal energy is a major problem with solar thermal systems. This is not the case with photovoltaics, since the electricity is usually fed in directly and the storage of the "public grid" is used. That advertising here, e.g. via links, is not welcome should basically not be a problem, as long as it is about the issue itself. Moreover, this whole matter now hardly has anything to do with the original question of the OP anymore, so it should actually be discontinued here. best regards