Avoid unpleasant surprises: what a high electricity bill reveals after installing a wall-mounted heat pump
At AirGreen, we install wall-mounted heat pumps across Montreal, Laval, Longueuil, the North Shore, and the South Shore with one goal in mind: to maximize your comfort while reducing your energy costs. So why do some homeowners notice a sudden increase in their electricity bills, even after installing a new and high-performance HVAC unit? In this article, we share real-world cases, the most common mistakes to avoid, practical advice, and our unique approach to ensuring your HVAC installation is truly cost-effective.
A brand-new wall-mounted heat pump: guaranteed efficiency? Not always.
It’s tempting to believe that a recent, high-performance system automatically ensures savings. But several clients have contacted us, dismayed, just weeks after the installation of a top-of-the-line wall-mounted heat pump, reporting a sudden spike in their energy usage.
Here’s why this can happen—even with the best brands like Fujitsu, Gree, Sharp, or Mitsubishi.
Mistake #1: improper sizing – too small or too powerful
Incorrect sizing is one of the most frequent issues. An overpowered unit will start and stop constantly (known as "short cycling"), consuming a lot of electricity without maintaining stable temperatures. On the other hand, an undersized unit will run continuously at full power, overheating its components and causing your power bill to shoot up.
At AirGreen, we perform a custom thermal analysis for every property. For example, in a recent installation in Sainte-Julie, we replaced a 12,000 BTU heat pump with an 18,000 BTU Gree Extreme model, perfectly matched to the home’s real needs, which reduced the electricity bill by 23% in the first month.
Mistake #2: poor configuration or improper usage
Even the best wall-mounted heat pump becomes ineffective if used incorrectly. Some clients allow indoor temperatures to fluctuate too much from day to day, overuse the “AUTO” mode, or keep interior doors closed, preventing airflow.
We recently assisted a client in Laval who, after installing a Fujitsu KZAH R-32, had the unit set at a constant 28°C. After a quick one-on-one training session with our team, she learned how to optimize the settings based on her lifestyle. The result: stable comfort and an 18% drop in her electric bill.
Mistake #3: poorly executed installation
A poorly done HVAC installation can lead to major thermal losses. We were called urgently to Longueuil after a client had a unit installed by a non-certified contractor. The outdoor unit was placed too close to a wall, limiting airflow, and the refrigerant lines weren’t properly insulated. After our complete reinstallation, the heat pump regained its intended efficiency, with a noticeable reduction in electricity consumption.
Mistake #4: air leaks or poor building insulation
Even the most efficient wall-mounted heat pump can’t compensate for major air leaks in a home. We found this issue in a duplex in Montreal where the windows were old and poorly sealed. After a full energy audit, the client carried out basic insulation work (caulking, weatherstripping), which immediately reduced heating demand—and therefore the heat pump’s electricity use.
Best practices to get optimal performance
1. Always choose a certified installer like AirGreen
Our installers are trained to meet the industry’s highest standards, ensuring an installation without performance loss.
2. Choose reputable brands
Manufacturers like Fujitsu, Gree, Bosch, Sharp, or Daikin offer advanced technologies like inverter compressors and eco-friendly refrigerants (R-32, R-454b), ideal for Quebec’s climate.
3. Schedule regular maintenance
Annual HVAC maintenance includes filter cleaning, pressure checks, and fault detection. A dirty heat pump can use up to 30% more energy.
4. Set your heat pump correctly
Avoid drastic temperature shifts and keep a consistent setting between 21°C and 23°C in winter, and between 24°C and 26°C in summer.
AirGreen case study: customer experience in Boisbriand
A customer in Boisbriand, on the North Shore, had a Sharp ZU1 18,000 BTU wall-mounted heat pump installed by AirGreen. Despite the high-quality unit, their Hydro-Québec bill rose 15% in the first two months. Upon inspection, we discovered excess humidity in the home, forcing the heat pump to run non-stop. We recommended a central dehumidifier, which stabilized humidity at 45% and brought energy consumption back down to normal.
Grants and financial incentives can offset poor performance… temporarily
Yes, Hydro-Québec’s LogisVert grants, which can reach $2,172, are a great incentive. But they should never hide the hidden costs of a poor installation or misuse. At AirGreen, our goal isn’t just to help you access rebates—we aim to provide long-term comfort and real energy savings.
Why choose AirGreen for your HVAC installation?
Our team brings over 15 years of experience in HVAC installation and maintenance throughout the Greater Montreal Area. We conduct custom energy analyses, use only CEE-certified products, and offer rigorous post-installation follow-up. Thanks to our proactive approach, more than 95% of our clients report a noticeable drop in energy bills within the first few months.
Conclusion: Is your heat pump an investment… or a poorly managed expense?
A wall-mounted heat pump that’s poorly sized, installed, or used may cost more than an old system. At AirGreen, we go far beyond simple installation: we analyze, advise, train, and offer complete after-sales service. That’s how we turn every HVAC project into a long-term success for our clients in Montreal, Laval, Longueuil, North Shore, and South Shore.
Contact us
Is your electricity bill unusually high despite having a brand-new heat pump? Contact the AirGreen team today for a full inspection, precise corrections, and expert advice tailored to your situation.