Warm bedroom in the house with ventilation including heat recovery

Without air conditioning and controlled residential ventilation: When we go to the bathroom in the evening to get "ready for bed," I first pass through the bedroom and dressing room and open the windows wide in both rooms so that air flows through both rooms. Overnight, the window usually remains slightly open. In the morning, everything is aired out nicely again and everything is fine.

Hi, why don’t you sleep with the window open overnight and the bedroom door closed?
Best regards, Barossi

Not everyone is lucky enough to live at the edge of the forest
If you live in the city, you just have noise, dirt, and exhaust fumes in the bedroom. (Welch schrecklicher Gedanke).

Not everyone is lucky enough to live on the edge of the forest

Being an allergy sufferer isn't always lucky either

My wife and I are both quite strong allergy sufferers, I don't notice much of a difference between the city and home, and the ventilation actually seems to be quite good (probably filters out quite a bit).

and the ventilation actually does good (probably filters out quite a bit)

Also a reason why we installed a controlled residential ventilation system with an F7 filter in our home. I'm curious to see what it brings during pollen season.