Surprising yet effective strategies to get the most heat out of your wall-mounted heat pump during the coldest months
The harsh Québec winter—with its biting cold and extended freezing periods—puts all heating systems to the test, including wall-mounted heat pumps. At AirGreen, we know that with a few lesser-known tricks — perfectly adapted to our climate — you can maximize the heat produced by your unit without increasing your energy usage. In this article, we reveal 5 unexpected tricks that savvy users in Montréal, Laval, Longueuil, the North Shore, and the South Shore are already using.
Optimized winter performance thanks to expert knowledge in action
At AirGreen, we don’t just install high-performance wall-mounted heat pumps. We support our clients throughout the winter so they can enjoy maximum comfort and savings from their system. Here are the tricks we’ve observed from experienced users — often inspired by real-life situations we’ve encountered during HVAC installations and service calls.
1. Use the "manual defrost" function before sunrise
What most people don’t know
Most modern wall-mounted heat pumps are equipped with an automatic defrost cycle. But during very cold nights, when humidity condenses on the outdoor unit, frost can reduce the system’s efficiency by morning.
Why it’s a smart move
Savvy homeowners in Laval and Saint-Hubert have started manually activating the defrost cycle around 5 or 6 AM, before heat demand spikes inside the home. The result: the outdoor unit is ready to work at full capacity right when the house starts to wake up—no delay, no performance drop.
2. Build a micro-shelter around the outdoor unit without blocking airflow
Inspired by our installations in Blainville and Boucherville
During a recent installation of an 18,000 BTU Fujitsu KZAH R-32 wall-mounted heat pump in Blainville, the client had already built a discreet wooden shelter around the outdoor unit—30 cm of clearance on each side, with full openings at the front and back. This prevented snow from building up on the fan while maintaining proper airflow.
Real-world benefits
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Fewer interruptions due to frost buildup
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Fewer wintertime service calls
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Consistent performance even during storms
3. Keep your heat pump at a constant temperature rather than turning it off and on
The classic approach: a hidden trap
Many homeowners turn off their wall-mounted heat pump at night to save energy, then turn it back on in the morning. But this forces the system to quickly catch up to a colder indoor temperature, increasing energy use and stressing system components.
What experienced users do
In Longueuil and the South Shore, several clients have told us they maintain their heat pump at a stable 20°C or 21°C day and night. The result: a steady, moderate operation that puts less stress on the compressor, avoids energy-hungry start-stop cycles, and ensures greater comfort upon waking.
4. Defrost the outdoor unit with lukewarm (never hot) water during extended deep freezes
A trick used in Repentigny and Candiac
During a maintenance visit in Repentigny, a client showed us how he carefully poured lukewarm water (never hot, to avoid thermal shock) on the base of his outdoor unit when it became encased in ice.
Why it works
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Frees up the fins blocked by frost
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Quickly restores airflow
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Prevents the need for the automatic defrost cycle, which temporarily shuts off heating
⚠️ This method must be used carefully, only when the system is off, and with gentle water flow to avoid damaging any electronic components.
5. Schedule preventive maintenance in November to avoid winter breakdowns
A profitable habit among our clients in Montréal and Laval
Many of the emergency calls we receive in January could’ve been avoided if maintenance had been done just before the deep freeze. Clients in Ahuntsic, Rosemère, and Saint-Lambert systematically request a full check-up in November, including:
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Cleaning of the indoor coil
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Refrigerant pressure checks
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Inspection of the condensate drain
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Early detection of unusual noise or vibration
The takeaway
Pre-winter maintenance means preventing heat loss when it matters most, extending your heat pump’s lifespan, and saving money on emergency repairs.
Our AirGreen approach: the small details that make a big difference
At AirGreen, our HVAC expertise goes beyond sales and installation. Every service call, every project, and every client allows us to deepen our knowledge, so we can better anticipate the needs of homeowners across Greater Montréal, Laval, Longueuil, the North Shore, and the South Shore.
Our certified installers always take the time to recommend best winter usage practices right from the startup of your new wall-mounted heat pump. We also guide you on maintenance, mistakes to avoid, smart habits, and even available grants like Hydro-Québec’s LogisVert program.
In summary: these 5 tricks can make all the difference
| Trick | Key Advantage |
|---|---|
| Early morning manual defrost | Better efficiency when you wake up |
| Well-designed shelter | Less frost, better durability |
| Constant temperature setting | Lower energy use, less mechanical stress |
| Lukewarm water defrosting | Gentle, fast solution for ice buildup |
| November maintenance | Fewer breakdowns, better performance |
Ready to optimize your system this winter?
Do you already own a wall-mounted heat pump, or are you looking to install a high-performance model for the cold season? Trust our HVAC specialists at AirGreen. We serve clients throughout Montréal, Laval, Longueuil, the North Shore, and the South Shore, with professional, fast, and tailored service for your specific needs.