Whole house ventilation – what does it mean?
As mechanical ventilation becomes a larger part of the high performance home building strategies, you'll hear a lot of talk about whole-house fan, whole-house comfort systems and so on. What does it all mean?
There are some distinctions that you should know to ensure your home has the correct style and amount of ventilation to ensure it meets building standards and provides a healthy and comfortable place to live.
You may hear Whole-House Fans, Whole-House Comfort Ventilators, and Whole-House Ventilation Systems. Unfortunately, these terms are used somewhat interchangeably, so it's confusing even to industry professionals. The Home Ventilating Institution offers some important distinctions between the terms:
Whole-house fan is the term properly used for the big fan that sits in the center of the top floor ceiling, between the house and the attic. It generally has louvers in the ceiling that are opened by the rush of air flow through the fan. The fan vents into the attic, pressurizing the attic and hopefully pushing the air out through the attic vents properly sized for the particular whole-house fan being installed. The purpose of the whole-house fan is to accelerate the natural cooling effect of bringing cooler outside air into the house through open windows and venting it out at the top of the house or the top of the “stack.”
Whole-house comfort ventilator is the term coined by the Home Ventilating Institute (HVI) to try to differentiate the whole-house fan from a whole-house ventilation system. A whole-house comfort ventilator is HVI’s term for a whole-house fan – they both essentially refer to the same product. The purpose of the whole- house comfort ventilator term was to distinguish a whole-house fan as a cooling product without implying that it is an air-conditioning system. Whole- house comfort ventilators and whole-house fans have no mechanical cooling element but rely on a natural temperature difference between the inside and outside of the home.
Whole-house ventilation system is a relatively new term for a mechanical system to move air through a house continuously at a relatively low flow rate. The purpose of a whole-house ventilation system is to provide a continuous air change for fresh air to maintain healthy living conditions for the occupants and the building itself, not to cool the temperature of the living space. So the purpose of a whole-house ventilation system is very different from the purpose of a whole-house fan or whole-house comfort ventilator.
Don't be confused by the very similar names for similar but different systems. It may take some questioning and explanation to understand the system that's right for your home, but it will help ensure your home performs as designed.
Find more home ventilation information here.