When an Installation Becomes a Nightmare: How to Spot the Critical Mistakes of a Poorly Installed Wall-Mounted Air Conditioner and Fix Them with Expertise
In the world of residential and commercial HVAC, the installation of a wall-mounted air conditioner isn’t just about attaching a unit to a wall. It’s a technical process that requires precision, expertise, and thorough execution. Unfortunately, many homeowners in Montréal, Laval, Longueuil, the North Shore, and the South Shore discover—often too late—that a poorly done installation can result in performance issues, energy inefficiency, and costly long-term damage.
At AirGreen, we’re frequently called in to correct botched installations carried out by unqualified contractors. In this article, we’re sharing our professional insight to help you quickly identify the warning signs of a poor installation—and to explain how we fix them, with a focus on transparency, safety, and efficiency.
1. The Wall Unit Is Poorly Positioned
A bad location can drastically reduce the system’s performance. If the unit is installed too close to the ceiling, behind a door, above a heat source, or in a poorly ventilated corner, the airflow will be compromised.
Why is this a problem?
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Poor distribution of cool or warm air
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Excessive energy consumption
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Premature compressor wear
How AirGreen fixes it:
We carefully evaluate each room, taking into account airflow, sunlight, and wall layout before proposing the best possible location, ensuring maximum thermal comfort.
2. The Drain Hose Is Leaking or Misaligned
A poorly installed drainage hose can lead to indoor water leaks, mold growth, and damage to walls or flooring.
Visible symptoms:
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Water stains on walls
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Dripping water under the indoor unit
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Musty odors
Our solution at AirGreen:
We install properly sloped drain hoses, protected against clogs and backflow. When needed, we use a professional-grade condensate pump with built-in alarm systems.
3. Refrigerant Lines Are Poorly Insulated
A careless installation may include poorly insulated refrigerant lines, which hurt the efficiency of the heat pump or air conditioner.
Consequences:
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Reduced efficiency
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Condensation
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Risk of freezing during winter
What we do:
We use high-density insulating sleeves and seal all connections meticulously. Each joint is pressure-tested with a leak detector to ensure perfect airtightness.
4. The Outdoor Unit Is Unstable or Poorly Ventilated
The outdoor unit must be securely installed on a stable support, protected from excessive snow buildup or direct sun exposure.
Signs to watch for:
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Unusual vibrations
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Excessive noise
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Poor operation during summer or winter
Our standards at AirGreen:
We install outdoor units on anti-vibration bases or galvanized wall brackets, ensuring a 12 to 18-inch clearance for optimal ventilation.
5. Exposed or Non-Compliant Electrical Wiring
Improper electrical connections can pose fire hazards or lead to short circuits.
What should never happen:
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Exposed wires
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Poorly sealed junction boxes
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No dedicated breaker
What we guarantee:
Our licensed electricians complete all wiring according to the Canadian Electrical Code, using protective conduits, GFCI breakers, and thorough final testing.
6. No Performance Testing After Installation
A complete post-installation check is essential. Too often, installers leave without testing performance metrics.
What you risk:
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A system that doesn’t cool or heat properly
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High electricity bills
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Early breakdowns
Our thorough approach:
At AirGreen, every installation ends with a full system startup, gas pressure check, temperature readings, and a sound audit.
7. No Follow-Up or After-Sales Service
A professional installation must include post-service support, something many fly-by-night installers neglect.
What you should expect:
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Installation warranty
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Responsive customer service
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Maintenance advice
What we offer at AirGreen:
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A complete client file
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10-year warranty on several of our products (conditions apply)
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An optional annual HVAC maintenance service, available by appointment
Botched Installation in Laval: A Real-World Example
A Laval customer reached out after having a Gree 18,000 BTU wall-mounted heat pump installed by an inexperienced contractor. The result: the indoor unit was leaking, the outdoor unit was dangerously vibrating, and the house was barely heated in winter.
We performed a complete removal and reinstallation, corrected drainage issues, replaced non-compliant wiring, repositioned both units, and restored optimal performance. The client is now eligible for a $1,704 LogisVert subsidy, since the new installation meets Hydro-Québec’s program standards.
How to Avoid a Botched Installation From the Start?
Our practical tips:
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Check the contractor’s RBQ license
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Ask for recent references
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Compare more than just prices: ask for a detailed quote covering every part of the installation
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Choose certified installers, like the experts at AirGreen
Why Trust AirGreen?
With over 15 years of experience in HVAC, our team works every week across Montréal, Laval, Longueuil, the North Shore, and the South Shore handling installations or repairs of wall-mounted air conditioners, wall-mounted heat pumps, and central systems. Our approach is transparent, human, and professional. Every project is documented, photographed, and explained to the client.
In Conclusion: What You Need to Remember
A poorly installed wall-mounted air conditioner can lead to a chain of technical, energy, and financial problems. By recognizing the key signs of a botched job, you can take action quickly—and ideally hand the job over to a contractor you trust.
At AirGreen, we specialize in diagnosing, correcting, and optimizing HVAC installations throughout Greater Montréal. Wondering if your system was properly installed? Contact us for a professional assessment.