Why Professional HVAC Installation in Montréal Matters: Avoiding Costly Mistakes That Drain Your Wallet
In the world of HVAC in Montréal, Laval, Longueuil, the South Shore and the North Shore, a simple mistake during the installation of a wall-mounted air conditioner can quickly turn a comfort solution into a financial nightmare. At AirGreen, we’ve seen firsthand—through hundreds of residential and commercial installations—how even seemingly minor mistakes can cost thousands of dollars in repairs, replacements, energy efficiency losses, or voided warranties.
In this article, we’re sharing our real-world expertise based on actual fieldwork to help you avoid the most common pitfalls during the installation of wall-mounted air conditioners or heat pumps. Whether you’re a condo owner in Montréal, a building manager in Laval, or a homeowner in Longueuil, the South Shore or the North Shore looking to upgrade your home comfort, these tips are for you.
Mistake #1: Hiring an uncertified contractor for the job
This is by far the most expensive—and unfortunately the most common—mistake. Many customers reach out to us after having their wall-mounted air conditioner or heat pump installed by unqualified contractors. The result? Poorly installed units, refrigerant leaks, non-compliant electrical connections, and performance far below what the manufacturer promised.
At AirGreen, we recently had to replace a botched installation in a duplex in Montréal-Nord: the customer had gone with an under-the-table contractor to save money. The outcome? An extra $4,300 in costs to fix the issues, not to mention the loss of the manufacturer’s warranty.
Mistake #2: Choosing the wrong BTU size for your system
Incorrectly sizing your system—whether too powerful or too weak—seriously impacts comfort and the lifespan of your air conditioner. All too often, homeowners pick a model based solely on square footage, ignoring insulation, sun exposure, ceiling height, or how the space is used.
In one case in Brossard, we recently removed a 24,000 BTU unit that was way too powerful for an 800 sq. ft. condo. The result? The system was constantly starting and stopping, causing premature wear and tear. We replaced it with a 12,000 BTU Fujitsu R-32 heat pump, perfectly suited for the space and offering optimal energy performance.
Mistake #3: Failing to follow electrical and safety standards
Installing a wall-mounted air conditioner or heat pump must comply with all aspects of the Quebec Electrical Code, including the breaker, wire gauge, grounding, and surge protection. Unfortunately, rushed jobs often overlook these crucial elements.
We fixed one such case in Laval, where an undersized cable led to dangerous overheating of the outdoor unit. Our certified team upgraded the system with a secondary panel and emergency shut-off switch, ensuring safety and full compliance.
Mistake #4: Ignoring Québec’s unique climate conditions
Our harsh winters and humid summers demand high-performing, properly calibrated HVAC equipment. Installing a unit without considering the specific climate of Greater Montréal guarantees poor long-term performance.
We always recommend units tested for Québec weather, such as the Gree Extreme R-410A or the Bosch BIVA IDS Premium R-454b, both of which operate efficiently down to -30 °C. One customer in Repentigny, who had chosen a unit not designed for the cold, saw their system fail during the very first winter. We replaced it with a Bosch central heat pump, and she now benefits from government grants and a 40% reduction on her electricity bills.
Mistake #5: Improper drainage and condensate management
A commonly underestimated mistake: poor condensate drainage. A misinstalled or backward-angled hose can cause water leaks, mold, and long-term structural damage.
We were called for an emergency in Longueuil, where a faulty drain slope led to water leakage inside the walls. We corrected everything with a gravity-fed drainage system, fully insulated to prevent freezing and ensure reliable year-round operation.
Mistake #6: Skipping regular recommended maintenance
Even the best HVAC installation loses effectiveness without annual professional maintenance. Clogged filters, dirty coils, misaligned fans—these can all shorten your air conditioner’s lifespan and raise your energy bills.
At AirGreen, we offer custom HVAC maintenance plans including inspections, full cleanings, refrigerant checks, and system recalibration. A customer in Saint-Jérôme, who had ignored maintenance advice, saw their system lose 25% efficiency in just 3 years. After our full maintenance service, the unit regained its original performance.
Best Practices Recommended by AirGreen
Always hire a certified RBQ contractor who’s a member of the CMMTQ
Our technicians strictly follow current regulations, ensuring a safe, efficient installation that keeps your manufacturer’s warranty intact.
Choose well-known brands with properly sized systems
We help you select models that truly meet your needs—whether it’s Fujitsu R-32 wall-mounted heat pumps, central Goodman units, or Bosch inverter systems.
Request a full thermal analysis before installation
Every installation begins with a thorough evaluation: heat loss calculations, room orientation, insulation, and lifestyle habits.
Make sure you qualify for available government grants
With our guidance, you can benefit from Hydro-Québec’s LogisVert grants, which can reach up to $2,172 depending on the model you install.
Why You Can Trust AirGreen for Your Wall-Mounted Air Conditioner Installation
With hundreds of completed projects in Montréal, Laval, Longueuil, the South Shore and the North Shore, our team offers more than just installation—we provide a complete, personalized, and certified approach. Each project is documented, followed up, and verified according to the strictest industry standards.
By avoiding the mistakes outlined above and choosing a professional installation with AirGreen, you’re securing not only your home comfort but also the longevity, energy performance, and overall return on investment of your HVAC system.