> If outside air makes up a significant fraction, the energy use can be enormous. This is what ERVs are for, conditioning incoming air from outdoors with the e

> If outside air makes up a significant fraction, the energy use can be enormous. This is what ERVs are for, conditioning incoming air from outdoors with the exhaust air. Enthalpy wheels are the most effective. https://en.m.wikipedia.org/wiki/Energy_recovery_ventilation https://en.m.wikipedia.org/wiki/Energy_recovery_ventilation > The article assumes buildings are air sealed. Which... they typically are not New buildings typically have a sealed building envelope/vapor barrier (excluding doors, obviously) and the HVAC system is balanced to account for pressure differentials. Commercial buildings typically don’t have operable windows, either.