A hidden flaw in a wall-mounted heat pump that led to major repairs
In the world of wall-mounted heat pumps, it’s easy to underestimate the impact of what seems like a minor technical issue. At AirGreen, we’ve encountered many situations across Montréal, Laval, Longueuil, and both the Rive Nord and Rive Sud where an imperceptible malfunction—like a tiny refrigerant leak—can have major financial and comfort consequences. This is the story of a Québec family whose unit appeared to work perfectly… until a costly surprise emerged months later.
The setting: a young family in Boisbriand, on the Rive Nord
The story begins in a modern semi-detached home in Boisbriand, where a young couple had recently moved in with their two children. The house was equipped with a wall-mounted heat pump installed by the previous owner, a 12,000 BTU unit from a mid-range brand, supposedly still under warranty. The couple enjoyed excellent cooling in the summer and sufficient heating through fall.
But when winter arrived, problems began.
The symptoms: poor performance, rising bills, and no clear warning
What’s dangerous with a minor refrigerant leak is that it doesn’t trigger an obvious alert at first. The heat pump still functions—but less efficiently. In this case:
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The heating took longer and longer to reach the desired temperature.
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The system began running continuously, never shutting off.
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The family's Hydro-Québec bill jumped by 45% between December and February.
Convinced it was a setting issue or perhaps the filter, the couple postponed calling for service. It wasn't until March, when warm air stopped coming out altogether, that they contacted AirGreen.
Diagnosis: a hidden leak that caused compressor failure
Upon arrival, our certified CVAC technician immediately noticed low refrigerant pressure. Using leak detection equipment, we discovered a microleak in the indoor unit’s coil—likely present for months. Because the system had been running undercharged, the compressor was overheating, eventually causing a complete failure of the main component.
This small undetected leak resulted in:
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Loss of the refrigerant charge
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Overconsumption of electricity
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Irreversible compressor damage
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A complete system replacement (not covered under warranty due to improper maintenance)
Why these leaks are hard to catch without professional inspection
Refrigerant circuits are sealed systems, and leaks are not always obvious. In a wall-mounted unit, the coils and connections are tucked away inside walls or concealed behind the evaporator. Without proper inspection tools and expertise, such defects go unnoticed.
Warning signs of a refrigerant leak:
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The system struggles to reach temperature
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Icing on indoor or outdoor components
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A faint hissing sound when the unit runs
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Frequent need to clean or replace filters
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Constant operation without achieving results
AirGreen’s solution: new installation with leak-proof verification
After explaining the diagnosis, we guided the family through a replacement process tailored to their home. We installed a Fujitsu KZAH 12,000 BTU wall-mounted heat pump, specially designed for cold climates, with:
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Inverter compressor for optimal efficiency
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Heating capacity down to -26°C
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10-year manufacturer warranty
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Eligibility for the LogisVert grant, saving over $1,000
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Leak testing and pressure verification before and after installation
We also installed a condensate pump and revised the drain line to prevent future water infiltration risks.
Three key takeaways from this incident
This situation is unfortunately common—and 100% preventable with proper maintenance and awareness.
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A small refrigerant leak can cost thousands if left unaddressed.
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Annual maintenance by a certified HVAC technician is essential to detect invisible issues early.
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Always choose recognized brands with robust warranties and certified installers like AirGreen.
What this family learned—and what every homeowner should know
This young couple in Boisbriand now has peace of mind thanks to a reliable and efficient heating and cooling system. Their energy bills have returned to normal, and they’ve scheduled their first annual inspection with us for next fall.
Their testimonial:
“We had no idea a tiny leak could destroy the whole system. AirGreen explained everything clearly and helped us find a solution that was both affordable and long-lasting. We finally feel secure in our home’s comfort.”
AirGreen’s expertise makes all the difference
At AirGreen, we’ve seen it all—from heat pump installations to emergency repairs after poor-quality jobs. Our expertise across Montréal, Laval, Longueuil, Rive Nord, and Rive Sud allows us to act quickly, advise clearly, and install systems that perform flawlessly for years.
If your heat pump isn’t running like it used to, don’t wait. A minor issue could be hiding a much bigger one. Contact our CVAC team today to avoid costly surprises.