Understanding how to use your thermostat with a wall-mounted heat pump is key to maximizing comfort, optimizing energy savings, and extending your system’s lifespan. At AirGreen, we’re often asked the following question: should you maintain a constant temperature or adjust it depending on presence or time of day? In this article, we share our professional expertise, field observations across Montreal, Laval, Longueuil, the North Shore and South Shore, and practical advice drawn from real customer experiences.
A Choice That Goes Beyond Personal Preference
Setting your thermostat to constant or variable temperature isn’t just a matter of comfort—it’s a strategic decision. This choice can directly affect your wall-mounted heat pump’s performance, energy efficiency, and your yearly heating and cooling costs.
We’ve analyzed dozens of real-life wall-mounted heat pump installations done by our teams in Montreal and the surrounding areas, factoring in home thermal behavior, occupant habits, and the technical features of the installed models.
Constant Temperature: A Stable Setting That Enhances Efficiency
Maintaining a constant temperature, day and night, is the method we most often recommend for homes equipped with modern high-efficiency wall-mounted heat pumps (such as the Fujitsu KZAH, Gree Sapphire, or Sharp ZU1 models). Here’s why:
The Advantages of a Constant Temperature
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Increased energy efficiency: Wall-mounted inverter heat pumps use less energy when maintaining a stable temperature, as they operate continuously at low speed.
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Greater thermal comfort: The indoor temperature remains steady, avoiding hot or cold spikes.
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Fewer start/stop cycles: Which reduces wear on the machine and extends its lifespan.
Real-Life Examples
In a recent project in Laval, we installed an 18,000 BTU Gree Sapphire wall-mounted heat pump in a single-family home. The client was initially inclined to use a variable hourly program but experienced reduced performance and nighttime discomfort. By switching to a constant 21°C setting, the system stabilized its energy use and comfort improved noticeably. The result: a 15% reduction in the following month’s electricity bill.
Variable Temperature: A Strategy That Fits Specific Cases
Changing the temperature based on occupancy periods may seem logical, especially if you're often away. However, this method doesn’t suit all wall-mounted heat pumps, or all types of homes.
When It Might Be Beneficial
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Well-insulated homes: With high thermal inertia, the temperature can be lowered for a few hours without significant loss.
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Sporadically used rooms: For instance, a guest bedroom can be heated occasionally.
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Units without inverter technology: Some basic models (often subsidized but less efficient) can better handle frequent start/stop cycles.
Risks and Drawbacks
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High energy use when restarting: Each reboot requires a greater energy output from the heat pump.
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Thermal discomfort: There's a delay before reaching the desired temperature again, especially during cold winter periods.
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Premature wear: Wall-mounted heat pumps aren’t designed to work like space heaters, but to maintain a stable climate.
Our Practical Recommendations Based on AirGreen’s Experience
What We Recommend in 80% of Cases
Keeping a steady temperature between 20°C and 22°C year-round is the most sensible choice, especially with the high-performance wall-mounted heat pumps installed by AirGreen. This method aligns perfectly with the optimal functioning of the inverter systems we install in most homes across Montreal, Longueuil, and the North Shore.
Special Cases
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Clients with irregular schedules (remote work, shift work): We adjust strategies by programming slightly reduced temperature periods, but never extreme drops.
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Low-use areas: We may suggest small adjustments, along with good airflow and door management.
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Multisplit installations: Each wall unit can be set independently. We optimize the settings based on room usage.
What the Heat Pumps Say Themselves
We work daily with brands like Fujitsu, Gree, Haxxair, Zephyr, and Sharp, and nearly all manufacturers recommend continuous and stable use for optimal performance. Installation manuals and technical training we follow at AirGreen all support this approach.
Technical Factors to Consider
BTU and Surface Area
A properly sized wall-mounted heat pump (not too big, not too small) allows for optimal continuous operation. For example, a 12,000 BTU Fujitsu is ideal for around 500 to 600 sq. ft., depending on insulation and sun exposure.
Grants and Efficiency
Programs like Hydro-Québec’s LogisVert often require compliant installation and optimal unit use. Intermittent usage could jeopardize expected performance levels during energy efficiency checks.
Practical Tips for Setting Your Thermostat Properly
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Choose the correct mode: Use heating or cooling mode only, avoid the “auto” mode that can switch back and forth.
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Turn off automatic eco modes if they shut the unit off at night.
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Check measured temperature accuracy: Place the thermostat away from heat sources or drafts.
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Clean your filters regularly: A clogged filter can interfere with temperature regulation.
Conclusion: Stability, Comfort, and Performance
Adjusting your wall-mounted heat pump thermostat is a key decision that affects your daily comfort and long-term savings. At AirGreen, backed by our experience across Montreal, Laval, Longueuil, the North Shore, and South Shore, we find that constant temperature settings win out in most cases.
Our team supports you in choosing, installing, and maintaining HVAC systems tailored to your needs. Every project is personalized, with a detailed thermal assessment, professional installation, and custom follow-up.