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Jusqu’à quelle température une thermopompe multizone peut-elle chauffer ? (Notre test par -30°C à Montréal)
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How Cold Can a Multizone Heat Pump Actually Heat? (Our Test at -30°C in Montreal)

Real performance, measured in the worst winter conditions

At AirGreen, we’ve always believed that multizone heat pumps can play a key role in both residential and commercial comfort—even during extreme cold snaps. However, many of our clients in Montreal, Laval, Longueuil, the North Shore, and the South Shore rightfully wonder: how cold can a multizone heat pump really heat efficiently? To answer this with precision and transparency, we conducted a real-world field test at -30°C in the middle of February in Montreal, using a high-end model we recently installed.

A full-scale performance test in Montreal

In a residential duplex located in the Villeray neighborhood of Montreal, we carried out the installation of a Gree Multi+ Extreme multizone heat pump, equipped with two wall-mounted indoor units of 12,000 BTU and 18,000 BTU. This system serves two main zones of the home: the living/dining area on the ground floor and the bedrooms upstairs. The outdoor unit was installed on anti-vibration mounts with optimal clearance for air circulation, even during snowstorms.

The goal of the test was clear: to measure the system’s actual performance during extreme temperatures, particularly below -30°C, during an Arctic cold snap in February 2025.

Technical specifications of the Gree Multi+ Extreme heat pump

  • Brand: Gree

  • Model: Multi+ Extreme

  • Total heating capacity: up to 36,000 BTU

  • High-efficiency Inverter compressor

  • R-32 refrigerant, more eco-friendly

  • Heating operating range: down to -30°C

  • ENERGY STAR certified

  • Eligible for Hydro-Québec's LogisVert rebate program: Up to $2,200 in grants

This model is known for its performance in cold climates, particularly thanks to its vapor-injection compressor and an electronic board specifically designed for freezing conditions.

Test results: proven efficiency at -30°C

Throughout the entire cold period, we monitored the heat pump’s performance in real time using ambient temperature sensors, power consumption data, and control curves. Here’s what we observed:

  • Outdoor temperature recorded: between -27°C and -31°C

  • Indoor temperature maintained: a stable 21.5°C in all served zones

  • Defrost cycle: efficient and fast, every 70 to 90 minutes, with minimal temperature loss

  • Electricity consumption: lower compared to a resistance-based heating system

Even in the dead of night with high winds, the system never required any auxiliary heating. This performance is a strong indicator of the reliability of a well-installed multizone heat pump, even in Montreal’s harshest conditions.

Installation and configuration: the key to performance

We want to emphasize a commonly overlooked point: this level of performance is only possible if the installation is done to the highest standards. Here’s what we did to ensure this installation was a success:

  • Thermal analysis of the zones to be heated

  • Precise BTU sizing per zone

  • Optimal refrigerant line length selection

  • Controlled incline of the condensate drain

  • Installation of a heated drain pan under the outdoor unit

  • Smart programming of defrost and recovery cycles

This is the level of HVAC expertise that sets AirGreen apart and allows us to guarantee optimal performance even under arctic conditions.

Other successful multizone installations in cold climates

Laval – Sainte-Dorothée: Single-family home

Installation of a Fujitsu AIRSTAGE multizone R-32 system with three wall-mounted heads. Stable performance down to -26°C, without the need for electric baseboard heaters. The homeowner was highly satisfied, especially impressed by the 45% reduction in their winter electricity bill.

Longueuil – Vieux-Longueuil: Rental triplex

Replacement of an old oil heating system with a Mitsubishi Zuba Central multizone heat pump. Guaranteed heating down to -30°C with a COP above 2.1 even in the harshest conditions. The property owner received maximum rebates thanks to our administrative support.

Tips for homeowners looking for a winter-ready multizone system

  1. Choose a heat pump designed for cold climates (operating range down to -30°C).

  2. Look for ENERGY STAR certification to ensure good efficiency.

  3. Hire certified installers with real-world winter experience.

  4. Request a personalized thermal analysis, especially for multizone setups.

  5. Take advantage of Quebec’s LogisVert grants while they’re still available.

Why trust AirGreen for your multizone heat pump needs?

We’re not just installers. At AirGreen, we are experts in residential and commercial HVAC, with hundreds of multizone systems installed throughout Montreal, Laval, Longueuil, the South Shore, and the North Shore. Our approach includes:

  • Custom energy analysis

  • Meticulous installation by certified technicians

  • Zone-by-zone optimization to maximize comfort

  • Post-installation follow-up, even during deep freezes

  • Support with rebate applications and government paperwork

Conclusion: A clear answer to a crucial question

Yes, a multizone heat pump can efficiently heat down to -30°C, as long as you choose the right equipment and entrust the installation to experienced professionals. Our tests prove it, our clients confirm it, and our results speak for themselves winter after winter.