Some discreet signs don’t lie: here’s when it’s urgent to replace your air exchanger
At AirGreen, experts in HVAC systems in Montréal, Laval, Longueuil, the North Shore and South Shore, we regularly intervene to inspect, repair, or replace defective air exchangers in residential and commercial buildings. Too often, we find that property owners wait too long before taking action, thinking the symptoms they’ve noticed aren’t serious. However, these small signs often point to major ventilation problems that can affect indoor air quality, energy efficiency, and even the health of occupants. Here are the warning signs you should never ignore.
Persistent and unusual smells in your home
When the air in your house starts to smell musty, moldy, or constantly dusty, it’s not just a matter of cleanliness or humidity. It often means that your air exchanger is no longer working properly—either because its filters are clogged, or its motor can no longer effectively renew stale air.
We recently intervened in Laval at a single-family home where the occupants were complaining about a persistent basement-like smell. Upon inspecting their 17-year-old air exchanger, we found a burnt-out motor and ducts clogged with dirt. The unit was replaced with a modern, high-efficiency Vanee model featuring state-of-the-art heat recovery technology, restoring optimal indoor air quality to the home within just a few hours.
A noticeable increase in humidity and condensation
Excess moisture in a well-insulated home is often linked to a faulty ventilation system. If you notice fog on your windows in winter, condensation on the walls, or mold spots starting to form, your air exchanger is no longer removing enough moist air.
On the South Shore, a couple in a modern condo called us after discovering mold behind furniture placed against the walls. The air exchanger, installed during construction, was undersized for the space and had never been serviced. After installing a high-performance HRV unit from Lifebreath, the humidity levels dropped back to healthy levels and the mold problems disappeared.
Unusual noises, inconsistent airflow, or no ventilation at all
A noisy air exchanger emitting strange sounds like clicking, humming, or grinding is a clear sign that a component is on its last legs—whether it’s a worn-out motor, damaged bearings, or an unbalanced fan.
In Montréal, at a duplex rental property in the Rosemont district, tenants were complaining of constant buzzing, day and night. We quickly diagnosed a 20-year-old Venmar unit with worn-out moving parts. Rather than carry out costly repairs, we recommended replacing it with a Venmar Gold Series model equipped with an ultra-quiet ECM motor. The result: restored acoustic comfort and a 35% reduction in energy consumption.
Visible deterioration of the equipment
Even without noise or odor, an air exchanger may reveal its age through visible rust, significant dust buildup, or deformed ductwork. These visual signs often mean the unit is no longer working efficiently inside. During an inspection in Longueuil, we found a device whose metal casing was rusted through and whose ducts were clogged with debris. It was no longer functioning at all.
We proposed a Fantech energy recovery ventilator (ERV) model, ideal for high-humidity environments and tightly sealed modern homes. Its installation, completed in just half a day, immediately restored a functional and energy-efficient ventilation system.
An unexplained rise in energy consumption
An inefficient or poorly maintained air exchanger has to work harder to get the job done. This often results in a gradual but noticeable increase in your electricity bill, especially if the motor is running non-stop without proper regulation.
On the North Shore, a homeowner reached out to us after noticing a 20% increase on their Hydro-Québec bill over the past year. We discovered that their unmaintained air exchanger no longer regulated its cycles and was running full speed 24/7. Replacing it with a Venmar EVO5 model equipped with an intelligent humidity sensor brought consumption back to normal, while improving air quality.
No maintenance for several years
Neglected maintenance is often the primary cause of air exchanger failures. Filters, recovery cores, and ductwork must be inspected and cleaned regularly. At AirGreen, we recommend annual maintenance, which includes:
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Cleaning or replacing filters
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Inspecting the core (HRV or ERV)
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Checking airflow rates
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Verifying electrical systems
When maintenance hasn’t been done for 5 to 10 years, it’s often more cost-effective to replace the system with a modern unit that’s more efficient and eligible for grants.
Why trust AirGreen to replace your air exchanger?
At AirGreen, we combine technical expertise, transparency, and personalized service to offer you durable and high-performance HVAC solutions. Our certified installers operate throughout Montréal, Laval, Longueuil, the North Shore, and the South Shore, ensuring flawless installations that meet the strictest standards.
We work with the top air exchanger brands in Québec: Venmar, Vanee, Lifebreath, Fantech, and always recommend systems that are tailored to your actual needs.
When should you replace instead of repair?
Here are a few simple criteria:
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The unit is over 15 years old
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Repairs cost more than 50% of a new model
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Energy efficiency is significantly lower than current models
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The unit no longer meets Building Code or LEED requirements
In these cases, replacement becomes the logical, cost-effective solution for your comfort and health.
Available grants for replacement
Good news: in certain cases, replacing your air exchanger with a high-efficiency model may qualify for LogisVert or Rénoclimat subsidies, especially if the work is part of a broader renovation. We’ll help you prepare your application at no extra charge.
Conclusion: Don’t ignore the subtle warning signs
An air exchanger showing signs of failure should never be ignored. Acting quickly helps preserve indoor air quality, optimize your home’s energy efficiency, and avoid costly repairs. At AirGreen, we support you every step of the way—from inspection to installation—ensuring your mechanical ventilation system operates at peak performance.
Need a full diagnostic of your air exchanger? Contact AirGreen today. We respond quickly throughout Montréal, Laval, Longueuil, the North Shore, and the South Shore to provide the solution that best fits your needs.