A costly mistake: what DIY wall-mounted air conditioner installations are really hiding
At AirGreen, we understand how tempting it can be to try and install a wall-mounted air conditioner yourself, especially when you're trying to save on installation costs. However, behind this apparent saving lie many risks, often irreversible, that can compromise not only the proper functioning of the unit, but also your home's safety and eligibility for grants. Today, we're sharing everything you need to know to avoid this costly mistake, and why hiring professionals like us is the smartest decision for your comfort, your budget, and your peace of mind.
The real dangers of a non-professional installation
Technical mistakes that void the warranty
Most wall-mounted air conditioners (whether they’re from Fujitsu, Gree, Sharp, or Bosch) come with limited warranties that are only valid if the installation was performed by a certified professional. A DIY installation will often immediately void the manufacturer’s warranty, meaning that any future malfunction will come out of your pocket—even if it’s a factory defect.
Risk of refrigerant leaks
Wall-mounted AC units rely on high-pressure refrigerant gases like R-32 or R-410A. Mishandling the connectors, poor soldering, or improper vacuuming of the circuit can lead to a leak, with serious environmental, financial, and health consequences. It also drastically reduces the unit’s energy efficiency.
Electrical safety and fire hazards
Incorrect wiring or using improper cables can lead to overheating, short circuits, or even house fires. At AirGreen, we always use CSA-approved materials and follow the Canadian Electrical Code to the letter—something you simply can’t guarantee with a DIY installation.
Poor performance and excessive power consumption
Wrong placement, incorrect sizing, or faulty connections can result in ineffective cooling. The result? A home that’s still too hot, higher electricity bills, and premature wear on the compressor.
A professional installation is an investment, not an expense
AirGreen’s expertise: our added value
Our specialized technicians work every week in Montréal, Laval, Longueuil, the North Shore and the South Shore, installing wall-mounted air conditioners in all types of properties: single-family homes, condos, multiplexes, businesses, and small commercial buildings. We understand the technical nuances of every brand and model, including the latest systems like:
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Fujitsu KZAH R-32: compact and quiet, ideal for condos.
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Gree Lomo Gen3 or Gree Sapphire: extremely energy efficient.
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Sharp ZU1: great value, perfect for large rooms.
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Bosch BOVA: praised for smart controls and reliability.
A complete and personalized service
We evaluate your space, cooling needs, and insulation to recommend the best HVAC solution. Our installation includes:
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Wall or floor mounting bracket.
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Core drilling and weatherproofing to code.
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Full vacuum pull of the system.
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Connection to the electrical panel.
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Complete operational testing.
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Submission to Hydro-Québec for LogisVert grants, often up to $1,860 in savings.
Grants: unavailable without a certified professional installation
Hydro-Québec’s LogisVert Program
This program encourages the adoption of energy-efficient equipment, but only if it’s installed by a company licensed by the RBQ and a member of the CMEQ, like AirGreen. A DIY install automatically voids eligibility, even if the unit itself meets the program's criteria.
A real example: Installation in Laval
A client wanted to replace his old AC unit with a Gree Lomo 18,000 BTU wall-mounted model. He tried to do it himself but damaged the copper coil, causing a major leak. Not only did the manufacturer refuse the warranty, but he had to buy a second unit and eventually called us to take over. The result: over $3,000 lost, and no chance for a grant. We restarted the project properly, installed the new unit correctly, and submitted a successful grant application.
The most common DIY installation mistakes
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Drilling through the wall at the wrong angle (causing condensation to back up indoors).
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No drain trap (leads to indoor water leaks).
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Improper vacuum (air bubbles reduce performance).
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Incorrect electrical calibration (wrong breakers).
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Poor orientation of the outdoor unit (exposed to too much sun or wind).
After-sales service that truly makes a difference
Hiring AirGreen means access to regular preventative maintenance, fast repair service, personalized advice to extend the life of your system, and quick intervention when needed. We maintain a full history of your installation, making future visits smoother and more efficient.
What you gain by choosing us
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Maximum performance from your unit starting on day one.
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Guaranteed access to all available grants.
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Electrical safety and code compliance ensured.
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Warranty preserved with the manufacturer.
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Peace of mind, no nasty surprises.
Conclusion: for your comfort and your wallet, make the right call
Installing a wall-mounted air conditioner isn’t something you can just wing. It’s not a “weekend project”—it’s a highly technical operation, with direct impacts on energy efficiency, safety, and the lifespan of your system. At AirGreen, we have the expertise, tools, and on-the-ground experience to guarantee a flawless HVAC installation, compliant with all standards and completed with attention to detail.
We serve all areas of Montréal, Laval, Longueuil, the North Shore and the South Shore, and are known for our quality workmanship, transparent guidance, and our commitment to customer satisfaction.