The Real Culprits Behind the Summer Surge: It's More Than Just the AC
When temperatures rise in Montréal, Laval, Longueuil, on the North Shore and South Shore, it’s not unusual to see electricity bills climb just as fast. While many immediately point fingers at their wall-mounted air conditioner or central heat pump, the reality is often more complex. At AirGreen, we work daily with homeowners and building managers across Greater Montréal to pinpoint the real reasons behind these unexpected spikes — and it’s not always what you’d think.
Understanding How a HVAC System Consumes Energy in the Summer
The heat pump or wall-mounted air conditioner is just one part of a much larger HVAC system. During the summer months, several factors directly affect energy consumption:
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Poor thermal insulation
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Leaky or improperly sealed windows
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Incorrectly sized HVAC system
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Outdated or poorly maintained equipment
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Excessive use of other electrical appliances
So even a high-efficiency wall-mounted air conditioner can end up consuming too much energy if the home allows heat to pour in.
AirGreen Case Study: A Troublesome Installation in Laval
Recently, we were contacted by a client in Laval whose bill was increasing by 60% every summer. She had invested in an 18,000 BTU wall-mounted Gree heat pump, known for its efficiency. After an inspection, our team identified several issues:
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The window caulking was old, letting warm air in.
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The unit was undersized for the true square footage of her condo.
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The air filter hadn’t been changed in over a year, forcing the system to overcompensate.
Once we addressed those issues — replaced the caulking, re-evaluated the system, and updated maintenance — her bill dropped by 40% the following summer.
Poor Insulation: The Silent Enemy of Your Wallet
Even the best heat pumps from Fujitsu or Bosch can’t compete with poorly insulated walls, ceilings, or attics. The cool air produced escapes as fast as it’s created, forcing the system to work non-stop.
AirGreen tip: Before investing in a new HVAC system, we always conduct a full thermal envelope inspection of the building. This allows us to recommend truly appropriate solutions and avoid energy cost overruns due to poor planning.
Neglected HVAC Maintenance = Guaranteed Overconsumption
A poorly maintained system is an inefficient one. In the summer, dust, pollen, and fine particles accumulate in your filters, coils, and ducts.
At AirGreen, we stress the importance of a thorough annual maintenance, which includes:
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Full filter cleaning
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Washing of interior and exterior coils
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Refrigerant pressure check
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Full system performance evaluation
We found at a client’s home in Longueuil that their Sharp 24,000 BTU unit was using up to 30% more energy just because of a clogged filter.
Poor Heat Pump Sizing: A Common Issue
One of the most frequent problems we encounter during our HVAC installations in Montréal and on the North Shore is improper unit sizing. Units that are too small run constantly. Units that are too powerful cause short and inefficient cycles.
At AirGreen, every installation begins with a precise thermal analysis of the space being cooled. This includes:
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The building’s sun exposure
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Number of floors and rooms
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Construction materials
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Internal heat sources
Thanks to this data, we choose the right model, brand (Fujitsu, Bosch, Goodman, etc.), and BTU capacity.
The Impact of Other Electrical Appliances
In the summer, your refrigerators, freezers, dryers, and other appliances can generate significant internal heat. If your HVAC system is already working at full capacity, these add-ons only increase energy consumption.
AirGreen tip: We often advise clients to run power-hungry appliances outside peak heat hours and to keep them away from thermostats to avoid false readings.
Modern Technologies and Available Rebates
Choosing newer models like the Bosch BIVA IDS Premium R-454B central heat pump or the FUJITSU KZAH R-32 wall-mounted heat pump helps maximize energy efficiency. These units are often eligible for Hydro-Québec’s LogisVert rebates, sometimes up to $2,000, depending on the setup.
AirGreen example in Montréal: A client in Outremont replaced an old system with a Bosch central heat pump. Thanks to our guidance, they received a $1,704 rebate and cut their summer bill by nearly 50%.
In Summary: What You Should Remember to Avoid Nasty Surprises
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Don’t just blame your air conditioner.
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Have your insulation, windows, and usage habits evaluated.
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Schedule regular HVAC maintenance.
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Rely on experts for proper unit sizing.
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Take advantage of available rebates when replacing an older unit.
At AirGreen, we don’t just install machines. We analyze the full environment to ensure maximum energy efficiency, while keeping you comfortable through the hottest months in Montréal, Laval, Longueuil, North Shore and South Shore.