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Indoor Air · MaintenanceHRV & ERV Cleaning & Balancing
HRV and ERV cleaning and balancing is a once-a-year service: filters, core, fans, drain pan and both outdoor hoods cleaned, then supply and exhaust airflow measured and set to within about 10% of each other. An HRV core is washed; an ERV enthalpy core is vacuumed only, because water ruins it. Homeowners can rinse the filters every two to three months, but the balancing needs a gauge.
A heat or energy recovery ventilator runs most hours of the year, pulling stale air from bathrooms and the kitchen area and bringing outdoor air in through a core that trades heat between the two streams. Everything the air carries ends up on the filters, the core faces and the fan wheels. Subdivision houses built since the 2000s in Milton, north Oakville, Waterdown and Brampton commonly have one hanging beside the furnace, and it is not unusual to find one that has never been opened. Servicing it is routine indoor air quality maintenance.
The outdoor hoods are where most airflow is lost. The intake hood has a screen that mats shut with dryer lint, poplar fluff, leaves and spider webs, and a blocked intake means the unit exhausts air it cannot replace. That puts the house under negative pressure: draughts at the doors, and a pull on the flue of any natural-draft water heater.
Inside the cabinet the core comes out. An HRV core, aluminium or polypropylene, is soaked in warm water with mild soap, rinsed and drained before it goes back. An ERV's enthalpy core is a moisture-permeable material that washing destroys, so it is vacuumed with a soft brush unless the manufacturer's manual says that specific core is washable. Fan wheels are brushed clean, and the drain pan and its trap are flushed and refilled so the unit does not gurgle or pull air through a dry trap.
Balancing is the last step and the one that gets skipped. With clean filters in, airflow is read at the unit's pressure ports or at flow stations in the ducts, and the balancing dampers are adjusted until the fresh and stale streams match. An unbalanced unit wastes heat recovery, frosts its core sooner in January, and either pulls the house negative or pushes moist indoor air into the walls. If the unit has a fault and not just dirt, that is HRV and ERV repair.
Book an HRV or ERV cleaning when
- It has been more than a year since the core was out, or you do not know when it last was
- Windows fog in winter even though the ventilator is running
- Airflow at the bathroom exhaust grilles has faded: a tissue no longer holds against the grille
- The outdoor intake hood's screen is furred over with lint or leaves
- The unit hums or rattles louder than it used to
How it works
The model on the cabinet door tells us whether the core is an HRV or ERV type and which filters to bring. Hood height matters too: two hoods at grade is a different visit from two under a second-storey soffit.
Filters, core, fan wheels, drain pan and trap are cleaned at the unit; the intake and exhaust hoods are cleared outside and their screens and flaps checked. The technician notes anything worn: a noisy motor, a cracked core, a defrost damper that does not travel.
Supply and exhaust are measured, the dampers set and locked, and the readings written on the unit for the next visit. You are shown how to pull and rinse the filters between services, and you can book the visit here.
Brands: We clean and balance Venmar, Lifebreath and other residential HRVs and ERVs.
Common questions
How often should an HRV be cleaned?
Rinse or vacuum the filters every two to three months and have the core, fans, drain and hoods serviced once a year, ideally in the fall before the windows close for winter. Houses with pets, a renovation in progress or an intake hood near the dryer vent load up faster. The manual for your model sets the exact interval; when it disagrees with a general rule, the manual wins.
Can I clean my HRV myself?
Parts of it. With the unit unplugged, the filters slide out and rinse in the sink, and the intake hood screen can be brushed clear from outside. Pulling the core is within reach of a careful homeowner on most models if you follow the manual on washing. Balancing is the part that needs instruments, and it should be redone whenever a deep cleaning changes the airflow.
Why can't an ERV core be washed?
Most enthalpy cores pass moisture through a treated paper or polymer membrane. Soaking strips the treatment, warps the layers or leaves the core unable to transfer moisture, and a replacement core is among the costliest parts in the unit. Vacuum the faces with a soft brush instead. A few newer ERV cores are rated washable; the label or manual will say so plainly.
What does HRV cleaning and balancing cost?
We do not publish a flat rate, because the visit varies: a washable core or a vacuum-only one, hoods at grade or on a second storey, balancing ports already on the unit or flow stations to add. It can share a visit with a furnace tune-up. You get the price in writing before the appointment, and our general rates are on the pricing page.
When is an old ventilator not worth cleaning?
When the core is cracked or warped, a fan motor is failing and no longer supplied, or the cabinet insulation is waterlogged from years of a blocked drain. Cleaning will not bring back the airflow or the heat recovery. At that point we price HRV and ERV installation instead, and our HRV vs ERV comparison helps with the choice of type.