Adopt the Right Habits to Protect Your Wall-Mounted AC System Against Quebec’s Harsh Winter
As the cold sets in and the first frost hits Montréal, Laval, Longueuil, the North Shore, and the South Shore, one crucial question arises for every homeowner with a wall-mounted air conditioner: how do you properly winterize your AC system to ensure its longevity, performance, and avoid costly repairs come spring? At AirGreen, experts in HVAC installation and maintenance, we see many clients each fall who are unprepared for this essential step. Here’s our complete guide—based on real on-site interventions and professional advice—to help ensure your wall-mounted air conditioner transitions smoothly through winter.
Why Winterizing Your AC Unit Is Essential
No matter how efficient, a wall-mounted air conditioner isn’t built to passively endure the extreme conditions of the Quebec winter. Without proper winterization, outdoor units risk:
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The buildup of ice and snow, damaging fins or the fan.
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Water infiltration that freezes, causing cracks in the casing or ducts.
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Premature deterioration of internal components, reducing overall efficiency.
For instance, we recently handled an emergency repair in Sainte-Thérèse on a Gree Extreme 18,000 BTU unit. The homeowner hadn’t protected the outdoor condenser, and snow infiltration led to compressor failure.
Key Steps to Effectively Winterize Your Wall-Mounted Air Conditioner
1. Cut Power to the Outdoor Unit
This is the first critical step. Even when turned off, a wall-mounted AC can automatically attempt to activate during mild spells. By cutting power, you prevent unintended cold-weather operation, especially on non-reversible models.
2. Thorough Cleaning of the Outdoor Unit
Before covering the unit, it must be completely cleared of any dust, dead leaves, debris, or plant matter. At AirGreen, our technicians always perform a gentle, controlled pressure wash, careful not to damage the condenser fins.
For example, during a preventive maintenance call in Longueuil, we found leaf buildup blocking the drains, which caused internal condensation. A proper cleaning would have avoided this.
3. Install a Proper Protective Cover
Use a cover that is waterproof, well-ventilated, and custom-fit to your model. A too-tight cover can trap stagnant moisture. We recommend specific covers for Gree, Fujitsu, or Sharp units, with integrated vent openings.
During a service call in Boucherville, a client had used a makeshift tarp: it trapped moisture inside, leading to internal corrosion. Since switching to an AirGreen-recommended cover, he’s had no issues.
4. Inspect the Indoor Unit
Winterization isn’t only about the outdoor unit. Make sure the filter is clean, that the ducts are dust-free, and that the airflow flap is closed to avoid passive heat loss.
5. Schedule a Professional Maintenance Check Before Winter
Nothing beats a full inspection by a certified AirGreen technician. During our seasonal maintenance visits, we check:
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Proper operation of sensors.
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Seal integrity of fittings.
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Refrigerant pressure (for dual-mode systems).
Every fall, we perform these checkups throughout Laval and Montréal, ensuring our clients can face winter worry-free.
Should You Use Your Heat Pump in Winter?
If your unit is a wall-mounted heat pump, it can be used for heating. But be careful: not all models are designed to operate efficiently at -20°C. Models like the Fujitsu KZAH 15,000 BTU or Gree Sapphire 18,000 BTU, which we regularly install in Montréal and on the South Shore, are optimized for Quebec’s climate. Lower-end models, however, may consume more energy without delivering optimal heat.
Our Custom Advice Based on Your Wall-Mounted AC Type
For non-reversible models (cooling only)
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Cut power in October.
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Apply a protective cover as soon as nighttime temps drop below 5°C.
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Plan a full cleaning in spring.
For reversible models (heat pumps)
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Keep the unit active if it’s designed for winter heating.
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Regularly clear snow around the compressor to prevent buildup.
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Schedule a mid-season maintenance check to confirm performance.
AirGreen Support: At the Heart of Your HVAC Needs
At AirGreen, our mission is to provide you with complete peace of mind for your HVAC systems. Our seasonal maintenance services are personalized and adapted to your unit and environment (urban, suburban, wooded area, etc.). We partner with trusted brands like Fujitsu, Gree, Sharp, Lennox, and Bosch, offering service tailored to each model’s specifications.
Real-World Examples of Successful Installations and Winterizations
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In Boisbriand, we protected a Bosch BOVA 36,000 BTU system with a custom drainage setup under the condenser base to prevent melted ice accumulation.
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In Saint-Hubert, we replaced an ill-fitting cover on an Arcoaire unit with a certified protective cover, reducing indoor heat loss throughout winter.
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In Montréal-Nord, a Gree Extreme 24,000 BTU wall-mounted heat pump has run flawlessly for 4 years thanks to our rigorous annual winter maintenance.
What to Remember
Poor winterization can drastically shorten the life of your system. By following the right steps—cleaning, power shutoff, protection, inspection—you safeguard your HVAC investment against Quebec’s harsh winter elements.
For complete, reliable, and professional support, trust AirGreen. Our experts operate across Montréal, Laval, Longueuil, the North Shore, and the South Shore, with precision and care.