When a Poor HVAC Installation Becomes a Nightmare for Homeowners
At AirGreen, we’ve unfortunately seen far too many clients reach out to us after living through a nightmare with a poorly executed wall-mounted heat pump installation. Whether it’s due to unlicensed technicians, incorrect sizing, or failure to follow industry standards, the consequences can be serious: premature breakdowns, water leaks, unusual noises, excessive energy consumption, and even voided manufacturer warranties. Through three real-life cases from different Montréal boroughs, we’re sharing true stories, filled with lessons about what to never repeat and the professional solutions we delivered.
Case #1 – The Flooded Compressor in Plateau-Mont-Royal
Location: Plateau-Mont-Royal
Original Unit: 12,000 BTU generic brand wall-mounted air conditioner – non-AHRI certified
Problem Encountered: water infiltration into the outdoor unit
When we arrived, the customer told us that after every heavy rainfall, her heat pump would shut down for several hours. The original technician had installed the outdoor unit directly on the ground, with no base, in a low spot on the property. The result? Every storm turned the area into a mini pool, partially submerging the compressor.
Our intervention:
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Complete disassembly of the unit
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Installation of a sturdy galvanized steel wall bracket
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Pressure testing and replacement of oxidized components
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Drainage upgrade and leveling
Final result: the unit was restored and elevated, protected from future weather events. Since then, the customer has reported no further shutdowns.
Case #2 – The Miswired 115V Unit in Villeray
Location: Villeray–Saint-Michel–Parc-Extension
Unit: Gree Lomo 9,000 BTU wall-mounted heat pump – 115V
Problem Encountered: electrical short at first startup
In this case, a client had a neighbor “handyman” attempt the installation. The result: inappropriate wiring, no dedicated breaker, and the unit connected directly to an existing wall outlet.
When the system was turned on, a short circuit tripped the power to the entire living room.
Our intervention:
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Full electrical inspection
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Installation of a dedicated 15A breaker in the panel
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Run of a new wire compliant with CSA standards
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Full certification of the connection, approved by Hydro-Québec
Thanks to our rapid response, no major damage occurred to the existing circuits, and the client was able to safely use the heat pump the very next day.
Case #3 – An Oversized Heat Pump in Rosemont
Location: Rosemont–La Petite-Patrie
Unit: Fujitsu 24,000 BTU wall-mounted heat pump – R-32
Problem: constant discomfort, frequent noise, short cycling
A client contacted us after having a 24,000 BTU heat pump installed in a 600 sq. ft. condo. Within weeks, he was complaining about constant discomfort: the room would swing quickly from too hot to too cold, and the system would turn on and off nonstop.
Diagnosis: the BTU capacity was vastly oversized for the space. The result? The heat pump “overheats” the area, creates short cycles (start/stop), increases energy use, and wears out the compressor prematurely.
Our solution:
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Removal of the 24,000 BTU unit (which we relocated to another client’s appropriately sized space)
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Installation of a perfectly matched Fujitsu KZAH 9,000 BTU heat pump
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Setup of a smart thermostat, with remote temperature sensor
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Fine-tuning of airflow for gentle, continuous diffusion
Result: perfect thermal stability, reduced noise, energy savings, and immediate client satisfaction.
Lessons Learned: How to Avoid a Bad HVAC Installation
Each case above could have been avoided if the basic principles of a professional HVAC installation had been followed:
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Proper BTU sizing based on square footage and room orientation
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Optimal outdoor unit placement, elevated and unobstructed
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Electrical compliance: dedicated breaker, correct wire gauge, grounding
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Use of AHRI-certified brands, compliant with Canadian standards
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Strict adherence to manufacturer-specific installation procedures
At AirGreen, we follow a strict protocol for every installation. We take the time to assess your space, your needs, your budget, and provide honest advice on the right model and configuration.
Why Trust AirGreen in Montréal
Our technicians are CMMTQ and RBQ certified, and hold valid trade licenses. We’ve completed over 1,500 wall-mounted heat pump installations in Greater Montréal, including the following boroughs:
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Plateau-Mont-Royal
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Villeray–Saint-Michel–Parc-Extension
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Rosemont–La Petite-Patrie
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Ahuntsic–Cartierville
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Mercier–Hochelaga-Maisonneuve
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Côte-des-Neiges–Notre-Dame-de-Grâce
Every installation is documented, inspected, and backed by a full parts and labor warranty.
In Conclusion: A Good Installation Is the Foundation of a Long-Lasting System
These three real-life stories show that a single overlooked detail can jeopardize your HVAC system’s performance for years. On the other hand, a job done right from the start, by professionals like AirGreen, ensures years of comfort, safety, savings, and peace of mind.
Not sure about your current installation?
Contact us for a free evaluation in Montréal.