A good wall-mounted heat pump doesn’t always guarantee optimal comfort at home
In Quebec, more and more households are investing in wall-mounted heat pumps to improve their thermal comfort while reducing energy bills. Whether in Montréal, Laval, Longueuil, on the North Shore or the South Shore, this HVAC solution has become one of the most popular choices for residential heating and cooling. Yet at AirGreen, we often see that even with high-performance units, comfort isn’t always as expected. Why? Because some frequent mistakes can compromise the intended results. Here are the most common ones, along with our recommendations on how to avoid them.
Choosing a poorly sized wall-mounted heat pump
A very common mistake, especially in older homes
Many clients, swayed by price or poor advice, choose a wall-mounted heat pump that doesn’t match the actual size of their space. For example, installing a 9,000 BTU unit in a 40 m² open-concept living room in Longueuil sets the device up to constantly overwork, leading to premature motor wear. Conversely, an oversized unit in a small room causes short cycling, which is harmful to the unit’s lifespan and reduces dehumidification.
Real-world example: Laval, Vimont neighborhood
At a client’s home in Laval, a 12,000 BTU Midea unit had been installed by another company for a double-exposure 35 m² room. The result: discomfort, constant noise, and high power consumption. We replaced it with a Gree Lomo 18,000 BTU, properly suited for the space, resulting in immediate comfort and lower electricity usage.
Poor placement of the indoor unit
The importance of height and airflow
The indoor unit must be installed at the right height (ideally 2 m above the floor) and in a clear area to promote even air distribution. Too often, we come across units placed:
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Just above a tall cabinet
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In a blocked wall corner
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Behind a ceiling beam
These poor placements hinder airflow, create stagnant zones, and reduce the system’s overall effectiveness.
Case observed in Montréal, Rosemont district
In a condo in Rosemont, a contractor installed a FUJITSU KZAH 15,000 BTU unit only 30 cm below the ceiling and near a structural beam. The result: pockets of hot and cold air, uncomfortable temperature swings, and ongoing complaints. We relocated the unit to a central, unobstructed wall, with an immediate improvement in temperature consistency.
Neglecting regular maintenance of the wall-mounted heat pump
A high-performance unit… that becomes ineffective without maintenance
Even top-tier heat pumps like the Bosch BOVA or Sharp ZU1 can become sources of poor thermal comfort if they’re not maintained properly. Clogged filters, blocked drains, dirty coils—these issues all restrict airflow and degrade system efficiency.
Our AirGreen maintenance service
At AirGreen, we offer annual HVAC maintenance plans that include:
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Filter and indoor unit cleaning
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Disinfection of the coil using non-corrosive products
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Refrigerant level checks
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Condensate drain inspection
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Blower performance tests
Proper maintenance ensures consistent thermal comfort and extends your system’s lifespan.
Underestimating the home’s insulation
A heat pump is not a magic solution
Even the best HVAC installation won’t compensate for a poorly insulated home. Cold walls, uninsulated attics, or aging windows can all limit how well the heat pump performs.
Example in Sainte-Julie, South Shore
A client invested in a Gree Extreme 24,000 BTU wall-mounted heat pump for a 100 m² ground floor. Despite the power of the unit, winter comfort was lacking. A thermal analysis revealed major air leaks around doors and windows. After sealing and replacing some frames, the system finally reached its full potential.
Installing a model unsuited for Quebec’s climate
Not all models are winter-ready
Some models marketed as “efficient” aren’t built to withstand extreme Quebec winters. Their heating performance drops sharply below -15°C, or even -10°C for the weaker ones. For consistent comfort, you need a wall-mounted heat pump that performs at -25°C or -30°C.
Our AirGreen recommendations
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FUJITSU KZAH
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Bosch BOVA
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Gree Lomo 23
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Sharp ZU1
All of these models have proven reliable on our job sites, even during deep freezes in Terrebonne, Boisbriand, and Saint-Hubert.
Summary: the keys to optimal thermal comfort with a wall-mounted heat pump
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Get a precise thermal assessment before buying
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Size the BTU output properly for your space
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Ensure correct indoor unit placement
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Schedule regular maintenance with professionals
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Upgrade insulation if needed
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Choose a model suited to Quebec’s winter climate
At AirGreen, we guide you through every step of your wall-mounted heat pump purchase and installation to ensure long-lasting, effective thermal comfort. Contact us for a free evaluation, whether you’re in Montréal, Laval, Longueuil, the North Shore or the South Shore.