Install an energy recovery ventilation system[1] [2]. If you have the money. 1. https://en.wikipedia.org/wiki/Energy_recovery_ventilation https://en.wikipedia.

Install an energy recovery ventilation system[1] [2]. If you have the money. 1. https://en.wikipedia.org/wiki/Energy_recovery_ventilation https://en.wikipedia.org/wiki/Energy_recovery_ventilation 2. Schematic picture: https://www.panasonic.com/nz/hvac/products/energy-recovery-ventilator.html https://www.panasonic.com/nz/hvac/products/energy-recovery-v...