When installing a multizone heat pump turns into a nightmare: the real-life story of a South Shore customer who barely avoided disaster
At AirGreen, we often meet customers who try to save money by installing their own HVAC systems, especially multizone heat pumps. Unfortunately, this decision can quickly lead to costly, inefficient, and sometimes dangerous complications. Today, we’re sharing the true story of a client located in Saint-Hubert, on Montréal’s South Shore, who nearly paid a high price for a project he thought he could handle on his own.
The context: an ambitious multizone project poorly assessed
Our client, owner of a four-bedroom bungalow, had purchased a Gree Multi+ Ultra multizone heat pump with 36,000 BTU capacity and three wall-mounted units (9,000, 12,000 and 18,000 BTU) to cover various areas of the home: the living room, basement, and master bedroom. Convinced he could follow online tutorials and armed with a few basic plumbing and electrical tools, he decided to take on the installation of his multizone heat pump himself.
Critical mistakes: faulty connections, leaks, and electrical hazards
Problems began to appear very quickly:
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Incorrectly sized refrigerant lines, leading to pressure loss and drastically reduced energy efficiency.
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Improper electrical wiring that didn’t meet building codes, creating serious risks of circuit overload.
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Improperly configured drainage, causing water infiltration behind newly renovated walls.
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Refrigerant leak (R-32), a situation both polluting and hazardous to health.
Within a week, the heat pump was no longer providing any thermal comfort, and the walls were already showing signs of moisture. That’s when our AirGreen team was urgently called in.
AirGreen to the rescue: a complete professional overhaul
As soon as we arrived, we carried out a full system evaluation. Here’s what we did to fix the situation:
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Replaced all refrigerant lines, professionally vacuumed and pressure-tested with nitrogen.
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Completely redid the electrical wiring, using a dedicated circuit breaker compliant with Québec code.
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Repositioned and leveled all wall units, with a tilted and heated drainage system—ideal for our Québec winters.
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Fully recharged the system with R-32 refrigerant, per Gree’s manufacturer specifications.
The intervention lasted three days, including leak testing, remote control configuration, and comfort optimization in each zone. The client immediately noticed a huge difference in terms of noise level, even temperature distribution, and reduced energy consumption.
Why a multizone heat pump requires professional expertise
Advanced technical knowledge required
Installing a multizone heat pump is not just about connecting a few pipes and mounting indoor units. It requires:
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Precisely calculating the thermal load for each zone.
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Choosing line lengths that match the compressor’s performance.
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Mastering vacuum and purging protocols to prevent internal contamination.
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Knowing the specific electrical and plumbing codes for Québec homes.
Specialized tools you simply don’t have
A typical homeowner doesn’t have:
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A commercial-grade vacuum pump,
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A certified digital manifold,
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A high-pressure nitrogen leak tester,
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Or the licenses required to handle refrigerants.
Without these tools and certifications, the installation becomes non-compliant, ineffective, and dangerous.
DIY installation = missed grants and lost savings
Another major issue: by installing it himself, our client became ineligible for several available rebates, including:
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The Hydro-Québec LogisVert program, which requires professional installation.
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South Shore municipal incentives tied to lowering carbon emissions.
By trusting AirGreen with his project, he could have saved up to $2,000 in rebates, not to mention benefiting from a 10-year warranty on parts and the compressor.
AirGreen: your trusted HVAC partner in Montréal, Laval, Longueuil, North Shore and South Shore
We install multizone heat pumps from reputable brands like Gree, Fujitsu, Tosot, Haxxair, Bosch, and Daikin, with constant attention to quality, performance, and safety. Every project is approached with a custom thermal analysis, meticulous installation, and responsive after-sales service.
We serve customers daily in Montréal, Laval, Longueuil, and across the North Shore and South Shore, with certified, punctual, and highly experienced teams.
Bottom line: HVAC projects should never be improvised
Installing a multizone heat pump is a major investment—not just for comfort, but also for your home’s value. But it’s also a complex system that requires expertise in climate engineering, a deep understanding of Québec residential construction, and thorough knowledge of HVAC codes and practices.
At AirGreen, we firmly believe it’s always better to invest in professional installation than to redo everything later—often at twice the original cost. This story from Saint-Hubert proves it clearly: it’s better to prevent than to repair.