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 seen it time and time again across Montréal, Laval, Longueuil, and throughout the North Shore and South Shore: a barely noticeable problem—like a tiny refrigerant leak—can lead to major financial and comfort consequences. This is the true story of a Québec family whose unit seemed to work perfectly… until an expensive surprise emerged several months later.
The setting: a young family in Boisbriand, on the North Shore
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 model from a mid-range brand, supposedly still under warranty. The couple enjoyed great cooling in the summer and decent heating through the fall.
But when winter hit, the trouble began.
The symptoms: weak performance, rising bills, and no obvious alert
What’s tricky about a small refrigerant leak is that it doesn’t immediately trigger any alarms. The heat pump still seems to function—but less efficiently. In this case:
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It took longer and longer to heat the home.
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The unit started running non-stop without ever shutting off.
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The family’s Hydro-Québec bill spiked by 45% from December through February.
Thinking it was just a setting issue or maybe the filter, the couple delayed calling a technician. It wasn’t until March, when the heat pump stopped blowing warm air altogether, that they contacted AirGreen.
Diagnosis: a hidden leak that destroyed the compressor
When our certified HVAC technician arrived, they immediately detected low refrigerant pressure. With specialized leak detection equipment, we identified a micro-leak in the indoor coil—likely active for several months. Because the system had been running while undercharged, the compressor overheated, eventually resulting in a total failure of the core component.
This small, undetected leak led to:
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Complete refrigerant loss
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Excessive energy consumption
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Irreparable compressor damage
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A full system replacement (not covered by warranty due to lack of maintenance)
Why these leaks are hard to detect without professional inspections
Refrigerant systems are sealed circuits, and leaks aren’t always obvious. In a wall-mounted unit, coils and connections are hidden inside walls or behind the evaporator. Without the right tools and expertise, these issues are impossible to spot early.
Signs that may indicate a refrigerant leak:
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Struggling to reach target temperature
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Ice buildup on indoor or outdoor units
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A faint hissing sound during operation
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Needing to clean or change filters frequently
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Constant operation with poor results
AirGreen’s solution: a new install with verified sealing
Once we explained the diagnosis, we walked the family through their replacement options. We installed a Fujitsu KZAH 12,000 BTU wall-mounted heat pump, designed specifically for cold Canadian winters, offering:
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Inverter compressor for optimal energy efficiency
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Heating capacity down to -26°C
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A 10-year manufacturer warranty
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Eligibility for the LogisVert grant, saving the client over $1,000
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Leak and pressure testing before and after installation
We also added a condensate pump and upgraded the drain line to eliminate any risk of future water damage.
Three key lessons from this case
Unfortunately, cases like this are common—but completely avoidable with the right approach and awareness.
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A small refrigerant leak can cost thousands if ignored.
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Annual maintenance by a certified HVAC technician is essential to detect invisible issues before they get worse.
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Always choose trusted brands with strong warranties and certified installers like AirGreen.
What this family learned—and what every homeowner should remember
This young couple from Boisbriand now has peace of mind with a system that’s reliable, efficient, and professionally maintained. Their energy bills are back to normal, and they’ve already scheduled their first annual tune-up with our team 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 urgent repairs caused by poor-quality setups. Our hands-on experience across Montréal, Laval, Longueuil, North Shore, and South Shore allows us to act fast, advise clearly, and install systems built to last.
If your heat pump isn’t performing like it used to, don’t wait. A minor issue could be hiding something much more serious. Contact our HVAC team today to avoid expensive surprises down the line.