ventilation & air quality
Goal: a building that is comfortable to live in, doesn't smell, and supplies its occupants with constant fresh air
We lose roughly a third of the heat in our house through leaks and unwanted convection. Some of us like to sleep with open windows in winter- how can one system take care of all this?
It's the passive house faction that really understands energy efficiency, ventilation, and air quality; these buildings are recommended for those suffering from allergies, respiratory illnesses or immuno-compromised persons, because the constant supply of fresh air is filtered thoroughly. Ditto city-dwellers.
A mechanical ventilation system that recovers the heat leaving your building is a low-tech, high-yield investment. Modern HRV systems retaining in excess of 90% of the energy from the air leaving the envelope.