The article mentions "Heat recovery ventilation", which means things like air exchangers [0] which pre-heat or pre-cool incoming air. It is an active ventilati

The article mentions "Heat recovery ventilation", which means things like air exchangers [0] which pre-heat or pre-cool incoming air. It is an active ventilation though, so you better run it periodically, even if you do not need heating/cooling. Your thermostat will have special setting for that, don't turn it off. [0] https://www.productcleaningsolutions.com/blog/what-is-an-air-exchanger https://www.productcleaningsolutions.com/blog/what-is-an-air...