If your Markham home was built in the last 15 years or so, it almost certainly has an HRV (Heat Recovery Ventilator) or ERV (Energy Recovery Ventilator) running alongside the furnace — a piece of equipment that homeowners in older housing stock elsewhere in the GTA simply don’t have to think about, and that a lot of new Markham homeowners don’t realize needs its own maintenance.
Why Newer Homes Need This at All
Modern building codes require homes to be built airtight enough that they no longer “breathe” the way older, leakier houses did. That’s great for efficiency, but it also traps stale air and humidity indoors — which is exactly what an HRV or ERV is there to fix, constantly exchanging indoor air for fresh outdoor air while recovering most of the heating or cooling energy in the process.
What Homeowners Often Get Wrong
- Treating it as optional. It’s easy to turn an HRV/ERV off or down because “it uses energy,” but that’s exactly backwards — it’s designed to recover most of that energy, and turning it off just traps humidity and stale air instead.
- Never changing its filter. An HRV/ERV has its own filter, separate from your furnace filter, and it’s commonly forgotten because it’s a less familiar piece of equipment.
- Ignoring condensation or frost on the unit in winter. This is a common early sign the core needs cleaning or the unit needs servicing, not something to write off as normal.
- Not realizing it’s connected to indoor air quality complaints. A stuffy house, persistent condensation on windows, or a musty basement smell in a newer Markham home often traces back to an HRV/ERV that isn’t running properly, not the furnace.
What to Do Now
- Locate your HRV/ERV — usually in the mechanical room near the furnace — and check whether it has its own filter that needs cleaning or replacing.
- Don’t turn it off to save energy; it’s built to recover most of what it uses.
- If you’re noticing stale air, excess humidity, or window condensation, have the unit checked before assuming it’s a furnace issue.
- Book a fall tune-up that explicitly includes the HRV/ERV, not just the furnace — many general tune-up quotes don’t automatically cover it.
If your Markham home’s ventilation system isn’t working properly, call our dispatcher — a technician can typically be on-site within 60 minutes, and we service HRV/ERV systems as a matter of course, not as an afterthought.