Maintaining your Heat Recovery Ventilator

Your heat recovery ventilator (HRV) can help make your house a clean, healthy living environment. It improves air quality by removing stale indoor air and continuously replacing it with preheated outdoor air.

An HRV can give many years of trouble free service. All it takes is a little bit of time to keep it running smoothly. The following maintenance schedule is easy to do and takes only a few minutes.

Before performing any maintenance always turn off the HRV and unplug it.


1. Clean or Replace Air Filters: Dirty or clogged filters reduce air flow and ventilation efficiency and should be cleaned about every two months. Open up the front panel and remove the filters. Clean with a vacuum cleaner then wash with mild soap and water before replacing. Older units may have replaceable filters.

2. Check Outdoor Intake and Exhaust Hoods: Check that the outside vents of your HRV are not blocked. Remove leaves, waste paper etc. During winter, clear any snow or frost buildup blocking outside vents.

3. Inspect the Condensate drain: The condensate drain is usually a pipe or plastic tube coming out of the bottom of the HRV. Slowly pour about two liters of warm, clean water in the drain inside the HRV and watch to see that it is flowing freely. If there is a backup, clean the drain.

4. Clean the Heat Exchange Core : Check your HRV owner’s manual for removing and cleaning the heat exchange core. Vacuum and clean with mild soap and water.

5. Clean Grilles and inspect the ductwork: Once a year, remove and inspect the grilles covering the ends of the ducts leading to and from the HRV. Vacuum if necessary.

6. Service the Fans: Make sure the unit is unplugged. Gently brush and remove dirt that has accumulated on the fan blades. Check your manual to see if lubrication is recommended. Older models may require a few drops of lubricating oil whereas newer models are designed to run continuously without lubrication.

7. Arrange for Annual Servicing: Your HRV should be serviced annually by a qualified technician accredited by the Heating, Refrigeration and Air Conditioning Institute of Canada (HRAI)


Turn your HRV off in April or May by either turning the dehumidistat control to HIGH setting or OFF
Turn your HRV back on in September or October and reset dehumidistat to 40% to 80%

New codes for furnace and hot water vents

In Ontario, beginning on August 2007, the Technical Standards and Safety Authority (TSSA) has adopted new national code requirements regarding the installation of plastic venting systems for gas burning appliances such as water heaters, boilers and furnaces.
PVC, CPVC or ABS piping has been used for many years but there have been reported cases of failure due to cracking, melting etc. causing potential unsafe conditions as a result of carbon monoxide leaking into the home. To address this situation the national installation code for natural gas and propane appliances has been revised. The new code stipulates that only plastic piping certified as gas vent (standard ULC S636) can be used for all installations of new and replacement natural gas and propane appliances.
Existing applications will not be affected unless there is a safety issue or the existing vent has deteriorated.

What this means to home owners is that the replacement of any furnace, water heater or boiler whether owned or rented will require upgrading of the plastic venting system. The existing vent will not be permitted to be reused. The cost of replacement and any work necessary to access the piping will be the responsibility of the homeowner.
In special circumstances, customers may apply to the TSSA for a variance, however note that this process will also require additional fees for testing and ongoing inspection in order to qualify. Additional information is available directly from TSSA at http://www.tssa.org/



Orange labels on pipe and fittings are required by
ULC S636 And clearly distinguish a certified gas
venting system from everyday uncertified pipe