Same in Denmark, we pretty much had to install one when building our house, to make up for energy loss from the large window area we wanted. We didn't have it properly calibrated at first, but once that was (professionally) done it has worked perfectly and kept a pleasant indoor-climate ever since.

The old-and-trusted brand here is https://www.genvex.com/en (ours was supplied by Ecovent though https://ecovent.dk/?lang=en )