Comment by gilbertbw

This is called MVHR (mechanical ventillation with heat recovery) in the UK. We're looking at putting it in, but have a fairly poorly insulated house, so it's not clear if the heat recovery is worthwhile. There is also PIV (positive input ventillation), which blows fresh air into a property (normally the hallways), but does not recover heat, or duct air from the rooms. So it's much simpler and cheaper to buy and install. It relies on the natural 'leakiness' of the property to vent stale air out.