Controlled residential ventilation yes - heat recovery no - justification in the text!

Guddi, then calculate 5x 10 minutes = 50 minutes per day for ventilation. In a year, that is 304 hours. Multiply that by your personal hourly rate (how many euros per hour do you work) and then compare it with the capital cost for the ventilation. Possibly also include depreciation of the system. I am quite sure that the controlled residential ventilation pays off.

One more question about the BluMartin - is it a directional switch? How do you prevent odors from the kitchen or bathroom from being periodically blown towards the living room?

That is a bit exaggerated, I would say. After all, I don't wait until I can close the windows again, but can do other things at the same time.

For example, I don't vacuum daily like some do. With your example, I also wouldn't be allowed to shave or would have to drive short distances under 2km by car instead of walking.

That is a bit exaggerated, I would say. After all, I don't wait until I can close the windows again, but can do other things in the meantime.

Well, in principle, you can take care of the other windows in the meantime. With us, there would be 10 windows to open in various rooms. By the time you’ve rushed through the whole house and picked up flying leaves, you can start closing the first window again (after 10 minutes). As has been mentioned often enough here in the forum, if someone is not actually at home for most of the day, the ventilation will be neglected. Then you don't spend 300 hours a year ventilating, but at best half of that, and with a bit of luck, you don't get mold. Then you can pat yourself on the shoulder and say you did everything right. However, the risk cannot be dismissed and exists in every new building without controlled residential ventilation.

We live in an apartment and have mold because we cannot properly ventilate and heat. Or in other words, because we cannot please the apartment. For the future, I have decided that it is more important to me to live healthily, not have any stench in the place, and above all that the house serves me. That there is a heat recovery system is a nice side effect that saves me from solar thermal energy.

This is what it looks like and you are literally throwing money out the window when airing...even though air is a poor energy carrier...nevertheless, when manually airing, you quickly have a few cubic meters of warm (e.g., 23°) air outside and bring in the same amount of cold air (e.g., -10°)...the temperatures are currently here with us...

This results in a difference (delta) of 33° which has to be compensated by the house/heating and repeatedly several times a day...

With my central controlled residential ventilation with heat recovery, I have a delta of barely 3° under the same conditions, if I can trust the temperature sensors, and I always have fresh air in the house...