A good air exchanger can change everything… if used properly
At AirGreen, we install air exchangers every week in homes across Montréal, Laval, Longueuil, the North Shore, and the South Shore. And yet, we still come across faulty or poorly used systems that do more harm than good to indoor air quality. The problem isn’t usually the brand or power of the unit — it’s about habits, maintenance errors, or questionable technical choices. In this article, we’ll show you the 3 most common mistakes, along with real-world solutions we implement daily for our clients.
Mistake 1: Never cleaning your air exchanger filters
This is by far the most widespread mistake, and also the most harmful. A clogged filter prevents the system from working properly, increases energy use, and allows pollutants to build up.
What we see in the field:
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Filters coated in thick dust, sometimes for years.
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Exhaust vents blocked by debris or mold.
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Systems making strange noises or underperforming.
The AirGreen solution:
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We offer a full annual maintenance service, which includes:
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Cleaning or replacing MERV or HEPA filters.
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Ductwork inspections.
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Airflow calibration.
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We recommend cleaning your filters every 3 months, especially during the winter.
Mistake 2: Installing an air exchanger that’s the wrong size for your home
We’ve seen too many undersized or oversized units installed without any real evaluation of the home’s needs. A unit that’s too small won’t circulate enough fresh air. One that’s too large dries out the air, causes discomfort, and wastes energy.
Real case: bungalow in Laval
A family contacted us after another company installed an ERV system. The result? Persistent humidity in the bathroom, fogged windows, lingering odors. After an inspection, we found that the unit was only pushing 90 CFM, when the home required at least 150 CFM.
Our solution:
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We removed the existing system.
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Installed a Venmar EVO5 500 HRV, offering adjustable 500 CFM airflow, built-in humidity sensor, and wall-mounted remote.
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Results within 48 hours: humidity stabilized at 45%, fresher and cleaner air.
Mistake 3: Keeping the air exchanger off most of the time
Many homeowners think the air exchanger should be turned on only occasionally, to save energy. That’s false. A good unit — especially models with ECM motors, like the ones we install — uses very little energy. And keeping it off for too long leads to stagnant air, mold growth, and viral spread.
What we recommend:
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Keep the unit running on low continuous mode at all times.
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Switch to temporary high-speed mode when cooking, showering, or hosting guests.
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Use the built-in settings to automatically adjust based on humidity levels (depending on the model).
Bonus: Other common mistakes and quick fixes
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Poor vent placement (too close to pollution sources)
➤ Solution: strategic repositioning or adding duct extensions. -
No dedicated outdoor air intake
➤ Solution: external wall drilling with backdraft damper and mesh screen. -
Vent blowing directly into sensitive areas (bedrooms, living rooms)
➤ Solution: adding diffusers or redirecting airflow.
Why trust AirGreen with your air exchanger?
We don’t just sell equipment — we deliver custom HVAC solutions for real-life problems. Every project starts with a personalized building assessment, precise system sizing, and a clean, certified installation.
Our advantages:
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Technicians trained to the highest industry standards.
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Top-tier products: Venmar, Lifebreath, Fantech, Vanee.
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Flawless installation, with proper airflow rates and electrical standards.
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Responsive after-sales service, including annual maintenance plans.
Practical tips to avoid unpleasant surprises
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Always ask for an indoor air quality assessment before choosing a unit.
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Choose systems that are ENERGUIDE-certified or ENERGY STAR® rated.
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Stick to a regular maintenance calendar (filters, ducts, unit box).
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Get to know your exchanger: we walk you through everything during installation.
In conclusion: a good air exchanger is only useful… if used properly
The best air exchanger on the market won’t help if it’s poorly installed, neglected, or misused. At AirGreen, we help you avoid the most common mistakes, optimize your system, and enjoy clean, balanced, healthy air throughout Montréal, Laval, Longueuil, the North Shore, and the South Shore.