What Is That Switch Above Your Thermostat?

November 16, 2019
Ever wondered what that switch is for above your thermostat?

Air To Air Exchange Systems

If you live in a home in Alberta that was built after 1998, you will have an air to air exchange system. These systems exhaust stale air and bring in fresh air to improve your home’s indoor air quality. These systems are now a requirement of the building code. LSM installs two types:

  • Exhaust fan (like a bath fan) could be located in your furnace room or hallway and in conjunction with your furnace system, work as an air to air exchange. The switch to activate this fan is usually in the hallway, near your furnace thermostat. This fan is wired to your furnace fan, so when the switch is turned on, it activates your furnace to circulate air which then brings fresh air into your home through your fresh air intake (a duct from the outside that goes directly into your ductwork). When this system is running, it could feel like your furnace is blowing cold air – this is normal.
  • Some homes may use an HRV (Heat Recovery Ventilator) – a unit designed specifically for air to air exchange. In a new home this unit is usually installed to take stale air from the bathrooms and kitchen replacing the bath fans and kitchen exhaust. It will draw fresh air directly from outside and warms it with the exhausting stale air (heat transfer via intersecting tubes) and delivers it directly to the rooms it draws from. This unit can be activated by a switch in the bathroom, like a bath fan switch.

It is recommended that you run your air to air exchange system several times per day, leave them on for 15 to 20 minutes and turn them off again. It’s also a good idea to run this system if you have excess amounts of humidity, cooking odours, and when other indoor contaminants are present (e.g. cleaning supplies). Leave this system off during your vacations or extended periods where the house will be vacant.

Check the outside of your home for the intakes and exhausts (they usually look like large dryer vent hoods). Keep these clear of any storage, debris, shrubs, and snow.

For more information, call our Residential Division at 780-532-4418.