Couldn’t find anything in the datasheets now. Maybe there’s something like that to retrofit...? But now one of the [Kontrollierte-Wohnraumlüftung] experts would have to answer.
One often reads that without a heat exchanger the air can become very dry, especially during the heating period, with [Kontrollierte-Wohnraumlüftung]. Whether that is true, no idea, we simply added it and will hopefully know just before Christmas how it "feels to live" with it. But thanks for your report. It reinforces our feeling that we made a good investment.
11,000 kWh per year is roughly 30 kWh per day. No matter what technology is installed, that is way too much, even with a server, air conditioning, controlled residential ventilation, etc. I already feel like a heavy consumer as a single person with about 3,000 kWh. But that also includes a home office with two computers and monitors, the large waterbed, and a lot of cooking.