When building an extremely well insulated and tightly sealed home it is imperative that a ventilation system be included in the design. Such a system runs continuously bringing in filtered fresh air from outdoors while exhausting an equal amount of stale air from the house. Rather than waste the energy in the conditioned air that is being sent out of the home, an ERV (Energy Recovery Ventilator) extracts this energy and transfers it to the fresh air entering the house. We have selected the Zehnder 600 Q to serve this purpose in our new home and it is able to recover up to 95% of that energy. Because of extended lead times, I placed an order for our system today so that it will be here in time for the HVAC work, currently planned for November.