Installation of a GREE FREEMATCH R32 GWHD(30)ND6MO 4-head wall-mounted heat pump in Contrecoeur, Montérégie

Four rooms, one compressor: the Contrecoeur project, from the first hole to the final joint

The project came to us in spring 2026 through a homeowner from Contrecoeur who had just completed a full renovation of the main floor of her bungalow: refinished ceiling, new trim, recessed lighting, varnished floors, and custom sheer curtains. Only one thing was missing from the picture: comfort. The house was heated with electric baseboards and cooled with two portable units installed in the windows. The front living room, converted into a home work studio, became unusable by the end of June.

The main constraint was not technical. It was visual and spatial: after the renovations, there was practically not a single unobstructed section of wall left. This is exactly the kind of project where an HVAC installation comes down to the inch, and where the choice of equipment matters less than how it is installed.

The state of the house before our work

The residence has approximately 1,250 sq. ft. on the main floor, faces southwest, and has a large patio door and a side window in the front room. The house was built in the early 1980s, with 2x6 walls and insulation partially redone during renovations. The finished basement remains temperate year-round and was not included in the project.

The stated requirements were precise:

• Cool four separate rooms: the front studio, the primary bedroom, a second bedroom used as an office, and a guest bedroom.
• Reduce the winter electricity bill, which was largely driven by electric baseboards.
• Do not install a floor-mounted unit or exposed ductwork in the rooms.
• Avoid noise: the client occasionally records video content in the studio.

A multi-zone system was essential. A central heat pump would have required nonexistent ductwork and an air handler in an already-finished basement. We therefore proposed a GREE FREEMATCH R32 multi-head wall-mounted heat pump, configured with four indoor units connected to a single outdoor compressor.

Why We Chose the GWHD(30)ND6MO Instead of the GWHD(36)ND6MO

This is the most interesting decision on the project, and the one most quotes never justify. Both models accept 2 to 4 indoor units. Both display 21 SEER2 and 10 HSPF2. On paper, they look similar. In practice, they behave completely differently.

The COP of 4.19 for the GWHD(30)ND6MO is the highest in the entire FREEMATCH range. The GWHD(36)ND6MO, by contrast, drops to 3.56—about 18% more electricity to deliver the same amount of heat under reference conditions. In a house heated six months a year in Montérégie, that difference is not cosmetic.

One detail the nameplate does not provide

The “30” in the model name refers to the nominal heating capacity (30,000 BTU/h). In cooling, the unit is rated at 28,400 BTU/h. A contractor who sizes the system based on the model name is off by 1,600 BTU/h from the very first line of the calculation. We read the specification sheet, not the label.

The diversity factor, with the actual project figures

We installed four wall-mounted heads totaling 39,000 BTU/h:

1. Front studio (the room in the photo): 12,000 BTU/h
2. Primary bedroom: 9,000 BTU/h
3. Office: 9,000 BTU/h
4. Guest bedroom: 9,000 BTU/h

That is 137% of the compressor’s rated cooling capacity. This figure makes people discovering multi-split systems do a double take, and understandably so: it would be absurd on a single-head system. On a multi-zone system, it is common and intentional. The four rooms never reach peak demand at the same time—the studio loads up in the morning and afternoon, the bedrooms at night, and the office only on weekdays. The G10 inverter modulates from 8,190 to 34,100 BTU/h in cooling and up to 40,900 BTU/h in heating, providing real reserve capacity well beyond the rated value.

However, we set a clear limit and tell clients about it before they sign: if all four rooms demand full capacity at the same time, each head receives less than its rated capacity. In this house, the electric baseboards have been retained as backup heat in the bedrooms—not because the system is weak, but because a January temperature of -25 °C in Contrecoeur, with wind blowing up from the river, calls for a second line of defense. The advertised heating range extends down to -30 °C, but the manufacturer publishes no remaining capacity at that temperature: we prefer to say what we do not know rather than promise a figure.

Installing a head above a patio door: the heart of the problem

The job-site photo shows the studio head, installed in the only strip of wall remaining: the vertical strip between the patio door and the side window, a few centimeters below the new ceiling.

Actual clearances, not the ones in the brochure

A wall-mounted head requires clearance above the unit so air can be drawn freely through the upper grille. If it is too close to the ceiling, it recirculates its own air, throws off its return-air sensor, and shuts off prematurely. We confirmed the available height before drilling, taking into account the ceiling molding that was already installed. We also checked the clearance on the window side so the front panel could open fully during annual HVAC maintenance—a detail that condemns dozens of installations to a halfhearted cleaning every year in Quebec.

The lintel: where we do not drill

Above a patio door is a structural lintel. We do not anchor a mounting plate to it or core-drill it to run a refrigerant line through. So we:

• located the studs and lintel with a detector, then confirmed them with a pilot drill;
• anchored the mounting plate in the double stud at the edge, below the level of the lintel;
• routes the bundle laterally, behind the curtain rod, rather than toward the rear at the center of the unit.

This lateral bypass is visible in the photo: the small white conduit running down along the trim, aligned with the molding, almost invisible once the sheer curtains are closed.

Condensate, by gravity, without a pump

A head installed very high is good news for drainage. The condensate drain runs from beneath the unit, maintains a continuous slope toward the outside, and passes through the wall above the level of the exterior ground. There is no condensate pump in this room: no buzzing during video recordings, no float to clean, and no equipment failure because a small $20 motor gave out on a scorching Sunday. Whenever gravity allows, we use it.

Airflow direction

The head blows toward the center of the room, diagonally, rather than directly toward the customer's workstation or chair. We also checked that the airflow would not brush along the freshly painted ceiling surface over its entire length, which would eventually leave gray marks around the recessed fixtures.

Eight copper pipes, four drains, a single electrical circuit

A four-head system starts with eight copper lines from the outdoor unit: one 1/4-inch liquid line and one 3/8-inch gas line per head. This is the part of the work the customer never sees, yet it determines the system's service life.

Lengths, charge, and weighing

The GWHD(30)ND6MO is precharged for 40 m of total piping, accepts up to 80 m, and allows a 25 m elevation difference. Our final survey showed approximately 46 m of total developed length for the four circuits. We therefore added R32 at a rate of 20 g per excess meter, or approximately 120 g, weighed on an electronic scale and recorded on the commissioning sheet. A multi-zone system charged “by the gauge and experience” is a system that will drift over ten years.

Evacuation, nitrogen, and leak testing

Every brazed joint was made under nitrogen; the entire system was pressurized with nitrogen for the leak test, then evacuated to 500 microns, with the hold verified before the valves were opened. In a four-circuit system, a single poor connection is enough to contaminate the entire system.

R32 and A2L leak detection

R32 is an A2L refrigerant, slightly flammable. The FREEMATCH series includes a leak detection sensor as standard, which is now a purchasing criterion in its own right. On our side, we verify the minimum area of each room served based on the system's total charge—here, approximately 2,320 g after the addition. It is a check that too many installers skip because it does not appear on any invoice.

A single power supply for the entire home

The indoor units are powered by the outdoor unit. Therefore, four circuits do not need to be run to the four rooms; a single 208/230 V circuit is run to the outdoor unit. With an MCA of 23 A and a maximum protection of 35 A, we installed a #10 AWG conductor and a 30 A double-pole circuit breaker, with a disconnect switch near the outdoor unit. In a home already heavily loaded with baseboard heaters, reducing the number of circuits at the panel can sometimes determine whether an entire project is feasible.

The outdoor unit: snow, river winds, and neighbors

The unit (1020 × 826 × 427 mm, 66 kg) was installed on an elevated support, above snow level and away from the roof edge to prevent ice from falling onto the top of the condenser. In Contrecoeur, exposure to winds blowing up the Saint Lawrence justifies this clearance: water from intelligent defrost must be able to drain away without forming a block of ice beneath the unit’s base.

The 62 dB(A) noise level at high speed influenced the decision to position the unit on the driveway side rather than beneath the neighbor’s bedroom window. We apply the same logic in Longueuil, Boucherville, and densely populated areas of Montréal, where municipal noise regulations are stricter than one might think.

Process and duration

Two technicians, two days. Day 1: drilling, mounting plates, piping, drains, wiring, and installation of the outdoor unit support. Day 2: connections, nitrogen purge, evacuation, opening the valves, commissioning, weighing the additional charge, testing all four indoor units in cooling and then heating mode, and training the customer on the remote control and filter cleaning.

What this Contrecoeur installation teaches South Shore homeowners

Five mistakes we regularly correct for customers

1. Adding up the capacities of the indoor units to choose the compressor. A total of 39,000 BTU/h does not require a 39,000 BTU/h compressor. This mistake systematically leads to oversizing, short cycling, and poor dehumidification.
2. Choosing the largest model “for safety.” Here, the GWHD(36)ND6MO would have cost more, consumed more (COP 3.56 versus 4.19), and required 45 A protection.
3. Installing an indoor unit without checking what's behind the drywall. Lintels, doubled-up studs, hidden electrical conduits: locating them takes ten minutes and avoids repairing a newly finished wall.
4. Installing a condensate pump as a reflex. Gravity never breaks down.
5. Forgetting that a multi-split shares a single refrigeration circuit. All indoor units operate in the same mode at the same time: you cannot cool a bedroom while heating the office. We explain this before the sale, never afterward.

Eligibility for rebates

The FREEMATCH R32 range is ENERGY STAR qualified and AHRI certified (214931588 for the GWHD(30)ND6MO's non-ducted configuration), making it the gateway to most financial assistance programs in Quebec. The criteria and amounts change from year to year, and eligibility depends on the heating system being replaced: a home heated with oil or propane does not qualify for the same benefits as a fully electric home like this one. We validate each application on a case-by-case basis and provide the required certification numbers in our project completion documentation, rather than advertising an amount that may not materialize.

Warranty and follow-up

The series comes with a standard 10-year warranty, extendable by an additional 2 years through Wolseley upon product registration with proof of installation. We complete this registration for our customers because one in three customers never does it and unknowingly loses two years of coverage.

Our service area

At AirGreen, we install multi-zone systems of this type in Contrecoeur, Verchères, Varennes, Sainte-Julie, Boucherville, and throughout the South Shore, as well as in Montreal, Laval, on the North Shore, and in Longueuil. Every project starts with an on-site, room-by-room assessment—never a phone estimate based on the total floor area. It's the only way to determine whether a GWHD(30)ND6MO is sufficient or whether you need to step up to a larger unit.

For a wall-mounted heat pump, a central heat pump, a wall-mounted air conditioner, or HVAC maintenance in Montérégie, our team assesses your home, prices the options, and explains the trade-offs before you sign anything.