Exclusive Comparison: Fujitsu vs Lennox — Which Heat Pump Performs Best at -25°C?

Two heat pump giants face off against Quebec’s winter: our in-depth analysis of Fujitsu vs Lennox

At AirGreen, we know that choosing the right heating system is no small decision—especially when you're up against the harsh winters of Montréal, Laval, Longueuil, the North Shore, and the South Shore. With temperatures dropping to -25°C or lower, you need a wall-mounted or central heat pump that delivers consistent, energy-efficient warmth. That’s why we decided to put two leading brands to the test: Fujitsu and Lennox, with a focus on how they heat in the extreme conditions of our Quebec climate.

Why this comparison is essential for Greater Montreal homeowners

Many of our clients are looking to replace outdated oil or electric heating systems with a modern, efficient, HVAC solution that qualifies for subsidies. Choosing a heat pump built for extreme cold can be a major long-term investment. That’s why it’s critical to compare these two renowned brands not just in terms of power, but especially for their reliability in subzero temperatures, energy efficiency, eligibility for government grants (such as Hydro-Québec’s LogisVert program), and maintenance costs.

A closer look at the contenders: Fujitsu vs Lennox

Fujitsu - KZAH R-32 Series (wall-mounted model)

• Heating capacity: down to -26°C

• Available BTUs: 9,000 to 24,000 BTU

• Refrigerant: R-32 (modern, low environmental impact)

• SEER (cooling efficiency): up to 26.5

• HSPF (heating efficiency): up to 13.4

• Whisper-quiet: as low as 21 dB

• Eligible for grants: up to $2,172 depending on model

• Typical AirGreen installation: quick, non-invasive, ideal for single-family homes and condos

Lennox - EL18XPV Series (central model)

• Heating capacity: performs down to -22°C (with electric backup)

• Available BTUs: generally 24,000 to 60,000 BTU (central heat pump)

• Refrigerant: R-410A

• SEER: up to 20.0

• HSPF: up to 10.2

• Compatibility: requires indoor furnace or coil

• Ideal for: larger homes, existing ductwork systems

• Grants: eligible depending on setup, up to $5,000 with Canada’s Greener Homes Grant

Performance at -25°C: the ultimate test

At -25°C, the main challenge isn’t just heating—it’s doing it efficiently without relying heavily on backup heating. Here’s what we observed, based on real-world installations by AirGreen:

Fujitsu KZAH R-32: reliability and consistency

In a home in Sainte-Julie (South Shore), we installed an 18,000 BTU KZAH model. The homeowner wanted a fully autonomous system with no electric backup. The result? Even at -27°C this past winter, the heat pump maintained a steady indoor temperature of 21°C without interruption, and the power usage was significantly lower than traditional electric baseboards. Fujitsu’s advanced inverter technology allows for precise power modulation based on heating demand.

Lennox EL18XPV: robustness and adaptability

In Boisbriand (North Shore), a 2,800 sq. ft. multigenerational home needed a central system to cover several zones. We installed a Lennox EL18XPV central heat pump paired with an electric furnace. Comfort levels were excellent, but at -24°C, the system needed to activate the electric backup. This isn’t a flaw—it’s standard in hybrid system designs. Lennox shines in uniform heating across large areas and in the durability of its components.

Technical breakdown and key takeaways

From the field: real projects we've completed

Montréal – Rosemont District

Ms. Tremblay contacted us to install a dual-zone Fujitsu KZAH 12k + 18k BTU system. The 1950s building couldn’t accommodate a central system. Thanks to the wall-mounted setup, the job was fast, discreet, and she qualified for $2,172 in grants. The result? A stable indoor climate at -25°C and a 38% drop in electricity bills.

Laval – Vimont

Mr. Doucet already had an older Lennox central heat pump from 2006. We replaced it with a new EL18XPV, integrating it with his existing furnace. We also added a Lennox iComfort smart thermostat to optimize usage. At -23°C, the system briefly activated the electric backup but held steady at 22°C throughout the house without any performance dip.

In conclusion: which heat pump performs best at -25°C?

Fujitsu edges ahead for small to mid-size homes without ductwork that need a high-efficiency system in extreme cold. Its R-32 refrigerant, energy ratings, and ability to heat without backup make it perfect for areas like Longueuil or Laval.

Lennox, on the other hand, remains a top-tier choice for larger homes with existing ductwork, where central distribution is key. It’s a proven, reliable option, particularly in dual-energy setups or when replacing an older central system.

Why choose AirGreen for your -25°C heat pump?

At AirGreen, we don’t just sell HVAC systems. We assess every home, every configuration, and every unique need to recommend the best solution. With our experience installing both brands, our certification for grant-approved installations, and our local expert teams on the South Shore, North Shore, and throughout Montréal, we’re your trusted partner for staying warm all winter long.