Is it worth paying the extra cost for KFW55 or not?

I have to say that I love my ventilation system. I don't want to do without it anymore. Especially during larger events in the house, I notice it clearly. The neighbors have window rebate ventilation with some strange motor. When they had the kitchen installation and a lot of sweaty craftsmen were bustling through the ground floor, it was running at full speed, which could unfortunately also be heard in the living room. I don't know if it was just set incorrectly, but it was not a pleasant experience.

I never hear him in the [WZ]. And besides, how do the neighbors feel about the thing? That you don’t like this cheap solution as much as your expensive solution is humanly understandable. Karsten

I never hear it in the living room. And besides, how do the neighbors perceive the thing? That you don’t find this cheap solution as good as your expensive solution is humanly understandable. Karsten

I wouldn’t call it a cheap solution. The unit (meaning the complete solution) was almost as expensive as our ventilation systems. They currently have the thing turned off. They have only been living in the house for 2 weeks. When the kitchen was installed, they were shocked at how loud the unit was under high load. A real humming noise, which could also be heard from the hallway. But as I said, it could also be that something isn’t set up correctly.

We deliberately chose KfW55. The additional cost for us was €5,000, exactly the amount you get in subsidies. We wanted a controlled residential ventilation system anyway because of the fan noise and humidity in the house. For €5,000, we had to increase the insulation by 2 cm all around, that was all that was necessary. We heat with gas including solar thermal energy. I wouldn’t take an air-to-water heat pump; with the humming noises, no one can sleep anymore.

We deliberately chose KfW55. The additional cost for us was €5,000, exactly the amount you get in subsidies. We wanted a controlled residential ventilation system anyway because of the ventilation and moisture in the house. For €5,000, we had to increase the insulation by 2cm all around, nothing more was necessary. We heat with gas including solar thermal. I wouldn’t take an air-to-water heat pump; with the buzzing noises, no one can sleep anymore.

What buzzing noises? I mean, it would also be stupid to put that thing next to the bed.

Our neighbor has such a system. Air-to-water heat pump installed indoors. I can hear the humming very clearly at night. We sleep about 10-15m away... I hear the noise clearly. Not for sensitive natures. I am already looking forward to our new home... no air-to-water heat pump all around.