HRV – Lungs for your House

Stale air, lingering odours and high humidity can happen in the best of homes and sometimes, simply opening a window can bring relief. When it’s mild outside and there is a breeze, opening a window can be beneficial. However, in Canada’s hot and cold climate this is not always practical or possible. Leaving a window open in mid-winter will add to your space heating costs, cause uncomfortable drafts and the window may freeze open.

Fortunately, there is another way of bringing fresh air into your home that is energy efficient, secure and highly effective – a heat recovery ventilator (HRV). HRVs are suitcase-sized appliances that typically have one fan to bring in outdoor air and another fan to push out the stale air. Heat is transferred from the outgoing air to the incoming air by passing the two air streams through a heat-exchange core, helping to reduce heating costs. As the two air streams are kept separated, only the heat is transferred to the incoming air. In a sense, an HRV can act as the lungs for your home.

In houses with baseboard or radiant heating, the fresh air from the HRV is delivered directly to the bedrooms and the main living areas through a dedicated duct system. At the same time, the HRV draws stale air from the kitchen and bathrooms and sends it outside. In houses with furnaces, it’s not uncommon to find HRVs connected to the furnace ductwork system.


Although you can buy an HRV at some home improvement stores, it may be preferable to have it designed and installed by a qualified contractor certified by the Heating, Refrigeration, Air Conditioning Institute of Canada or other training organizations in accordance with current building codes and standards. It is very important to measure and balance the supply and exhaust airflows to ensure the HRV does not create dangerous house depressurization or pressurization problems. This should be carried out when the HRV is first installed and be checked regularly afterwards by a qualified contractor in accordance with the manufacturer’s instructions. Look for units with lower energy usage and high energy efficiency in the heating season, preferably choosing from those with an ENERGY STAR® rating.


HRVs require minimal annual maintenance to ensure energy efficient and safe operation. At the beginning of each heating season, clean the filters and heat recovery core, and ensure the drain pan and pipes are clean and clear. Inspect and clear the screens in the outdoor intake and outlet hoods. Check the manufacturer’s literature for requirements.

While there will always be times when opening a window to allow a refreshing breeze to air out your home is desirable, HRVs offer an effective and efficient way to get the ventilation you need.

For more information on sustainable technologies and practices for new housing and renovations, visit CMHC’s website at, or call Tom Levesque, Manager, Communications & Marketing, at 902-426-1811



Canada Mortgage and Housing Corporation (CMHC) is Canada’s national housing agency. Established as a government-owned corporation in 1946 to address Canada’s post-war housing shortage,