Installation of a GREE FreeMatch R32 two-head wall-mounted heat pump (GWHD(30)ND6MO) in Montréal-Est

The air at the eastern tip of the island does not affect an appliance the way it does one in a suburb.

An outdoor unit of a heat pump is a heat exchanger in the open air: thin aluminum and copper, permanently exposed and carrying thousands of cubic meters of air per hour. What that air contains matters just as much as its temperature, and it is the only parameter that appears on no technical data sheet.

In Montréal-Est, residential areas border a large industrial and petrochemical sector that has been active since 1913. Elsewhere on the island, road salt, construction dust, and traffic emissions produce comparable effects on a smaller scale. At AirGreen, we install HVAC systems in Montréal, Laval, Longueuil, on the North Shore, and on the South Shore, and the area's atmosphere is a factor we record before choosing a location.

What we installed in Montréal-Est

Two heads on the third model in the lineup, and why

A two-zone project almost always ends up on the smallest available unit. The GWHD(30)ND6MO accepts two to four indoor units, so it is perfectly legitimate with two heads, and we selected it here for a reason related to the environment rather than the house.

You buy margin where the environment will consume it. In an area where the air deposits material and causes corrosion, a unit ages by attrition: a few dulled fins, a coil that becomes slightly less efficient each year, and a charge that may slowly decrease. In a system sized just right, this degradation immediately costs comfort on a heat-wave afternoon. In a system installed at 63% of its rated capacity, it first costs margin—and margin is what it is there for. This is an exposure-based argument, not a power-based one.

The two heads are also identical, which is no coincidence either: a single filter reference for the entire house, identical behavior from one room to another that occupants learn once, and no zone oversized relative to the other.

Two characteristics of the model support this logic:

• Refrigerant charge. 2,200 g of R32 rather than 900 g in the smallest model: the same loss represents a much smaller proportion of the system, which matters precisely where a slow leak caused by corrosion is the risk to monitor. The reverse demonstration, using the smallest unit in the range, appears in our Côte Saint-Luc article.
• Piping range. 40 m of precharged piping, 80 m of total length, and 25 m of elevation difference, compared with 15 m on the two smaller models. When the outdoor-unit location is chosen based on prevailing winds rather than convenience, this range has tangible value. The complete reasoning behind going from 15 to 25 m as a reason to change models, along with an analysis of the range's performance, is developed in our Pierrefonds-Roxboro article.

The trade-offs, stated to the customer before the order: the unit is heavier (66 kg), bulkier, noisier (62 dB(A) versus 54 and 58), and requires a 35 A MOCP instead of 25 A, which is not insignificant with an older panel. Its 8,190 BTU/h modulation floor also leaves very little leeway for a 9,000 BTU/h head operating alone. In practical terms, a single zone in mild weather operates very close to the system floor and cycles more often; both zones together, at a moderate setpoint, are the operating range in which this unit is most comfortable. The mechanism is explained in our Saint-Chrysostome article, and the workaround in the one on Saint-Urbain-Premier.

What actually attacks an outdoor unit

The outdoor coil is made of aluminum fins crimped onto copper tubes. Two different metals, in contact, in the open air: this configuration ages well in neutral air and much less well elsewhere. Three aggressors dominate in Québec:

• Salt. De-icing salt thrown up by traffic and snow removal, and sea spray near large bodies of water. Chloride attacks aluminum through pitting and accelerates galvanic corrosion between the two metals.
• Acidic compounds. Industrial atmospheres, combustion emissions, and certain organic vapors make the moisture deposited on surfaces slightly acidic. Copper is vulnerable to a form of corrosion that creates microscopic channels in the tube wall.
• Deposits. Soot, fine dust, greasy residue: they do not directly eat away at the metal, but they continuously hold moisture against it, which amounts to the same thing after three or four years.

Corrosion does not trigger any error code

That is what makes it costly. The sequence is always the same, and it is slow:

1. The fins become dull, then turn white and develop pits. The heat-exchange surface decreases.
2. The unit compensates by running longer. No one notices anything: there is no noise, alarm, or message.
3. A microscopic perforation appears in a tube. The refrigerant escapes over a period of months.
4. The system eventually shuts down on a low-pressure fault, several seasons after the problem begins.

On a system with R32, this slow leak has an additional consequence: the charge of a multi-zone system is calculated and weighed, and a gradual loss throws off the operation of the expansion valves in each branch long before shutdown. Diagnosis takes longer and costs more on a multi-zone system than on a single-zone system, and that is one more reason to treat corrosion as an installation issue rather than a repair issue.

Where to place the unit when the air is aggressive

Location matters just as much as equipment. Our clearance rules, which we apply everywhere—not just in industrial areas:

• Three metres from a dryer vent. This is the clearance most often overlooked and one of the most damaging: dryer air is hot, humid, and laden with lint, and lint sticks to wet fins like a filter.
• Away from kitchen and bathroom ventilation outlets and combustion-appliance vents. A coil placed in a plume of stale air breathes it all year.
• Three feet from the electrical box, twenty-four inches from the Hydro-Québec meter, and two metres from property lines. These three clearances relate to safety and neighbors rather than corrosion, but they are part of the same placement decision.
• Outside the path of the snowblower and the snow-throwing zone, where road salt arrives with the snow.
• On a drained base, so defrost water can run off instead of pooling beneath the unit. The base is discussed in detail in our Rigaud article.

Cleaning frequency is determined by the environment, not the calendar

The complete method for cleaning an outdoor coil—the steps a homeowner can do themselves, the ones that can destroy a unit in ten minutes, and why we rinse against the direction of airflow—is published in our Pierrefonds-Roxboro article, and we refer readers there rather than repeating it.

What changes in an area like this is only the frequency, and that is a contractual rather than technical matter. Once a year is a suitable baseline for an ordinary residential neighborhood. Along a salted road, in a dusty environment, or near industrial facilities, twice a year is more realistic, with one visit in spring before the first heat wave and another in fall after the air-conditioning season ends. We include this in the maintenance contract at signing, explaining why, rather than offering it as an extra three years later when performance has already declined.

Only one corrosion-specific point needs to be added to the general method: rinsing a coil exposed to salt has value beyond cleanliness. Fresh water washes away deposited chloride before it can work against the aluminum all summer. In a salty area, a spring rinse is as much an anticorrosion measure as a performance measure.

Questions to Ask Before Buying for a Corrosive Environment

The FreeMatch commercial sheet says nothing about corrosive atmospheres—no coil treatment, restriction, or recommendation. This is a gap we point out rather than filling it with an assumption. Three questions must therefore be put to the distributor before ordering, and the answer becomes part of the file:

1. Is there a factory-applied protective treatment for the coil on this model, and is it available in Québec?
2. Does the site's atmosphere affect warranty coverage—corrosion is frequently treated as environment-related wear rather than a manufacturing defect.
3. What maintenance frequency does the manufacturer require to maintain the warranty in this type of environment?

A contractor who answers “that’s not a problem” without asking these questions has not asked them.

What the unit will not do for indoor air

A necessary clarification in a sector where the question keeps coming up: a wall-mounted heat pump recirculates the room's air through a coil. It does not introduce outdoor air, and its filter is a protective screen for the coil, not an air purifier. It therefore does not treat odors or volatile organic compounds. The answer to these needs is an air exchanger with appropriate filtration, and the full reasoning appears in our Beauharnois article.

What a heat pump is really worth when the house changes hands

This is the question clients ask last, often on the doorstep, and one that almost no one in our industry answers honestly.

What a buyer looks at—and what they cannot see

A buyer sees one outdoor unit and two wall-mounted heads. They do not see the deep vacuum, the tightening torque of the flares, the weighed charge, or the port matching—in other words, everything that determines whether the unit is an asset or a future expense. These details are covered in our Côte Saint-Luc article.

A building inspector, for their part, verifies that the unit starts, blows cold or hot air, has no visible water leaks, and that the outdoor unit is not damaged. This is an operational check, not an installation inspection, and they measure neither the charge nor the system's tightness. A favorable inspection report therefore does not attest to the quality of the installation—it attests that the unit was working on the day of the visit.

What remains, to prove what remains, is the paperwork.

The warranty: 10 years, 12 years, and the question of transfer

The manufacturer's published coverage is 10 years on the compressor and parts, extended to 12 years when the product is registered with proof of installation. Two clarifications we provide systematically:

• Registration is done once, at the end of the job. We handle it with the client rather than simply handing them a form. An unregistered warranty is a ten-year warranty, which is still good, but the difference costs nothing.
• Transferability to the next owner depends on the manufacturer's and distributor's program conditions, and must be verified with them, with the file in hand. We do not assert it on the manufacturer's behalf. This is precisely the kind of point a seller wants to have verified before putting the house on the market, not during negotiations.

The file that makes the difference

What we provide at the end of the job and what stays with the building:

• The exact model of the outdoor unit and each head, with the serial numbers associated with their respective components.
• The AHRI code for the combination actually installed—an AHRI rating qualifies an outdoor + indoor combination, never a single unit, as explained in our Saint-Anicet article.
• The developed line-set lengths and the quantity of refrigerant added and weighed.
• The commissioning records and proof that the vacuum held.
• The contractor's RBQ licence and the invoice.
• The maintenance history, which is something an insurer needs just as much as a buyer does.

A buyer who receives this file no longer has to make assumptions. This is also what distinguishes a unit installed by a licensed contractor from one that no one knows anything about.

What we do not promise

We promise no percentage increase in resale value. A wall-mounted heat pump is first and foremost a comfort project, with an energy dividend for heating—the wording and what a contractor can honestly commit to delivering are discussed in our Rigaud article. What we observe, without putting a figure on it: in a market where air conditioning has become a search criterion, the absence of a system is more often a reason to negotiate the price down than its presence is a reason to raise it. It is an asymmetry, not a return.

The photo: a head above an opening, between a cornice and a mirror

The installation shown in this image brings together three constraints we encounter in carefully designed interiors.

• The decorative plaster cornice runs along the wall-ceiling junction and had to be interrupted to accommodate the unit. The rule is simple, and it must be decided before drilling: the upper clearance is measured to the nearest obstacle, not to the ceiling. The complete treatment of a wall with moldings appears in our Dorval article, and the clearances around the casing in the one about Verchères.
• The full-height wall mirror, directly below the unit, is the least obvious constraint. A glued or clip-mounted mirror provides no anchoring point, cannot be drilled, and will crack if work is carried out too close to its edge. It also prevents any line routing behind it: the copper and drain paths must be determined before the indoor unit's position is presented to the client, otherwise an impossible location may be promised. A mirror also reflects the unit back into view, doubling its visual presence in the room—an aesthetic consideration we raise, but never allow to take precedence over the drain slope.
• The position above an opening means the lintel must never be drilled, and the door's travel must be checked with it fully open.

One final practical observation: the unit blows toward a neighboring room through the opening. This distributes some of the comfort, but a closed door cancels it out, and no indoor unit serves two rooms separated by a closing door.

Montréal-Est: a 12 km² city where residential areas and industry meet

Montréal-Est is a city in the Montréal agglomeration, reconstituted on January 1, 2006, after the 2002 merger, at the eastern tip of the island. It covers just over 12 km² and has approximately 4,000 residents, with much of its territory occupied by industrial and petrochemical facilities, the first of which date back to 1913. The residential sector is compact, largely old, and directly adjacent to this activity.

Three consequences for a heat pump installation in this area:

1. The outdoor unit's location should be chosen with the prevailing winds and what they carry in mind—not just the regulatory clearances.
2. Coil maintenance is a performance condition included in the contract, at a frequency suited to the environment, not an option sold later.
3. Residential construction is often old and compact: masonry walls, plaster, trim, narrow backyards and nearby neighbours. The method for checking municipal regulations appears in our Huntingdon article, and the question of the neighbour's window in the Côte Saint-Luc one.

Mistakes to avoid

• Placing the outdoor unit in front of a dryer vent or ventilation outlet.
• Cleaning the coil with a pressure washer or household degreaser.
• Covering the unit for the winter.
• Waiting for an error code before worrying about a loss of efficiency. Corrosion and buildup do not produce one.
• Selling a house without the equipment file. Without documentation, a properly installed system and a poorly installed one look the same.
• Neglecting to register the warranty, which extends coverage from 10 to 12 years with proof of installation.

Commissioning, maintenance and financial assistance

Commissioning includes a leak test, a deep vacuum with a rise test, weighing the additional refrigerant charge, functional testing of one head at a time in both modes with a physical check of the room being served, and recording the serial numbers. The electric baseboard heaters remain in service, set below the heads' setpoints.

Routine maintenance comes down to two tasks: rinse the filters every 4 to 8 weeks during the intensive season, and have the outdoor coil cleaned—once a year elsewhere, twice a year in an area like this one.

As for financial assistance, an electric residential installation may qualify for LogisVert and be part of a Rénoclimat process; the Chauffez vert program does not apply to a dwelling already heated with electricity. The criteria change, and we verify them when the file is opened.

For a wall-mounted heat pump installation in Montréal-Est, Pointe-aux-Trembles, Anjou, elsewhere in Montréal, Laval, Longueuil, on the North Shore or the South Shore, we document the site environment before choosing a location and provide documentation to prove it ten years later.