How a Heat Recovery Ventilator Works
Heat recovery ventilation systems allow R-2000 homes to maintain high indoor air quality without excessive additional energy costs.
As shown in the diagram below, a heat recovery ventilator (HRV) consists of two separate air-handling systems – one collects and exhausts stale indoor air; the other draws in outdoor air and distributes it throughout the home.
Components of a Heat Recovery Ventilator
At the core of an HRV is the heat transfer module. Both the exhaust and outdoor air streams pass through the module, and the heat from the exhaust air is used to pre-heat the outdoor air stream. Only the heat is transferred; the two air streams remain physically separate. Typically, an HRV is able to recover 70 to 80 percent of the heat from the exhaust air and transfer it to the incoming air. This dramatically reduces the energy needed to heat outdoor air to a comfortable temerature.
Maintaining Your Heat Recovery Ventilator (HRV)
Your heat recovery ventilator (HRV) can help make your house a clean, healthy living environment, while keeping fuel bills down. But your HRV can't do all this without your help.
It only takes seven simple steps to keep your HRV happy…
The Seven Steps to a Happy HRV
Step 1: Turn Off Your HRV
First, turn off your HRV and unplug it.
Step 2: Clean or Replace Air Filters
Dirty or clogged filters can lower ventilation efficiency. Try to clean your filters at least every two months. Filters in most new HRVs can be easily removed, cleaned with a vacuum cleaner, then washed with mild soap and water before being replaced. Older units have replaceable filters. If your HRV is easily accessible, this is a five-minute job.
Step 3: Check Outdoor Intake and Exhaust Hoods
Remove leaves, waste paper or other obstructions that may be blocking the outside vents of your HRV. Without this vital airflow, your HRV won't function properly. During winter, clear any snow or frost buildup blocking outside vents.
Step 4: Inspect the Condensate Drain
Check to see if your HRV has a condensate drain — a pipe or plastic tube coming out of the bottom. If it does, slowly pour about two litres of warm, clean water in each drain pan inside the HRV to make sure it is flowing freely. If there's a backup, clean the drain.
Step 5: Clean the Heat Exchange Core
Check your HRV owner's manual for instructions on cleaning the heat exchange core. Vacuuming the core and washing it with soap and water will reduce dust that can build up inside the core.
Step 6: Clean Grilles and Inspect the Ductwork
Once a year, check the ductwork leading to and from your HRV. Remove and inspect the grilles covering the duct ends, then vacuum inside the ducts. If a more thorough cleaning is required, call your service technician.
Step 7: Service the Fans
Remove the dirt that has been accumulated on the blades by gently brushing them. Most new HRVs are designed to run continuously without lubrication, but older models require a few drops of proper motor lubricating oil in a designated oil intake. Check your manual for complete instructions.
Your HRV should be serviced annually. If you are not comfortable doing it yourself, contact a technician accredited by the Heating, Refrigeration and Air Conditioning Institute of Canada (HRAI). Make sure the technician you call has been trained by the manufacturer of your HRV.