The brick on a suburban home is not a brick wall
On the residential streets of Saint-Bruno-de-Montarville, a great many homes have full-height façades made of solid clay brick. To the eye, it is masonry. At the anchoring point, it is not.
This 2-head GREE FreeMatch R32 heat pump installation began with a refusal: we refused to attach the outdoor unit to the wall the customer showed us, even though it was the shortest, most discreet, and most convenient wall. The article that follows explains why, because this is exactly the question a South Shore homeowner should be able to ask three contractors.
The project in brief
- City: Saint-Bruno-de-Montarville, Longueuil agglomeration, Montérégie / South Shore
- Outdoor unit: GREE FreeMatch R32 GWHD(30)ND6MO
- Heads: 18,000 BTU/h in the open main-floor area, 9,000 BTU/h in the primary bedroom
- Total installed capacity: 27,000 BTU/h, or 95% of the 28,400 cooling rated capacity and 90% of the 30,000 heating rated capacity, well below the 34,100 BTU/h maximum modulated cooling capacity
- Piping: 12 m and 16 m, for a total of 28 m of developed length, within the 40 m factory charge—no R32 added
- Installation: flat roof of the rear addition, on a four-legged aluminum base placed on wooden sleepers
- Electric baseboard heaters: retained
- AHRI codes: 214931588 (ductless), 214931594 (ducted), 214931598 (mixed)
What's behind the brick
A brick wall on a Quebec single-family home built between the 1960s and today is almost always a veneer: a single layer of brick about 90 mm thick, built in front of the wood framing and separated from it by an air gap.
The assembly, from outside to inside:
- The brick, which rests on the foundation or on a steel angle and transfers its own weight all the way down.
- The drained cavity, with weep holes at the bottom of the walls and above openings—those open vertical joints that homeowners mistake for a masonry defect.
- Metal ties that connect the brick to the framing. They do not support the brick; they keep it from tipping.
- The weather-resistant barrier, the intermediate cladding, then the framing and insulation.
The consequence can be summed up in one sentence: brick stands upright, and that is all it supports.
Three consequences for a 66 kg appliance
Brick only supports itself
The GWHD(30) weighs 66 kg empty. Added to this mass are the wind load on a 1,020 × 826 mm surface, and above all a constant vibration produced by a compressor that modulates for thousands of hours per year. An anchor installed in a 90 mm veneer takes all of this through a skin that was never designed to carry anything beyond its own weight.
Our Sainte-Clotilde page discusses anchoring a wall-mounted head into solid interior brick, and we will not revisit it here: it is a different problem, a different mass, and different masonry. Here, the difficulty is neither the hardness of the material nor the choice of drill bit: it is the distance between the visible surface and the first thing that actually carries the load, and the fact that this distance is occupied by a void that must not be filled.
The cavity must continue to drain
A brick veneer is not watertight and has never claimed to be. Water passes through the joints, runs down behind the brick, and exits through the weep holes. Any intervention that blocks this path turns a wall that functions into a wall that accumulates water.
Hence three firm rules for this type of façade:
- No weep holes are obstructed, whether by improvised flashing, a bracket, or foam.
- The cavity is never filled at a penetration. Expanding foam sprayed into a drained cavity is a repair that becomes visible six years later, through efflorescence and deteriorated mortar joints.
- The penetration is sleeved and sloped outward, and the flashing is arranged so that water flowing behind the brick can continue to drain out.
Brick moves
Clay masonry moves with the seasons and over time, and well-built walls include control joints designed to absorb this movement. A rigid device fastened without taking these joints into account becomes the point where movement stops, and that is where the crack appears. On a façade wall, this crack is not a minor technical issue: it is masonry repair visible from the street.
Let's add what our customers learn too late, especially in a sector where the residential building stock is thirty or fifty years old: a removed brick cannot be replaced like-for-like. Colors and sizes go out of production, and the repair remains visible. The same reasoning we published for trim and profiles in Dorval applies here, with far less tolerance.
What can be fixed into brick, and what cannot
This is not about attaching nothing. It is about classifying:
- Acceptable: fasteners for a refrigerant line set, a line-hide cover, flashing, or a lightweight disconnect box—in other words, low, static loads without vibration.
- To be treated as an engineering case: a condenser bracket. The anchor must reach the structure, which means passing through the cavity without closing it off, with hardware and a rod length selected for what they need to reach. This can be designed, but it is not something to improvise on a ladder on a Tuesday morning.
- Never: an anchor installed in a mortar joint to support a load, a bracket attached to a lintel above an opening, or a fastener immediately next to the edge of a veneer panel.
Why the unit ended up on the roof
Since the façade was ruled out for the reasons above, and the rear yard of this property did not allow for a ground base at a reasonable distance from both heads, the unit was installed on the flat roof of the rear addition, on a four-legged aluminum base resting on wooden sleepers that distribute the load across the membrane.
We do not develop the rules for rooftop placement here: they belong on our existing pages, where they are covered in detail—the interface with the membrane and the roofer’s warranty (Dollard-des-Ormeaux), existing mechanical equipment on the roof (Pointe-Claire), galvanic corrosion and maintaining level over time (Pierrefonds-Roxboro), lifting billed as a separate line item (Rivière-des-Prairies–Pointe-aux-Trembles), and the sunlight exposure of a light-colored membrane (Lorraine). What matters for Saint-Bruno is simpler: the roof was not chosen because it was convenient; it was chosen because the wall was unsuitable, and that decision was made during the technical visit, not on installation day.
Mistakes to avoid on a brick façade
- Attaching a condenser bracket to the mortar joints because the drill bit enters them more easily.
- Filling the cavity with foam “to keep cold air out” around a penetration.
- Sealing an improperly executed penetration with caulk, thinking that solves the water issue.
- Drilling immediately above an opening, in the lintel area.
- Accepting a quote that does not say where the outdoor unit will be installed or what it will rest on.
The rooms we do not serve
One two-zone system serves two rooms. This is the part of the explanation that every quote includes. The part that few contractors put in writing is this: the other rooms receive nothing, and that needs to be stated before signing rather than discovered in July.
Our Baie-D'Urfé page addresses the upstream question—the method for choosing which two rooms to serve—and we will not repeat it here. What follows is the downstream question, the one that arises once the choice has been made.
What really happens in an unserved bedroom
Three observations, in the order in which clients make them:
- The unserved bedroom does not become hotter than before. It remains exactly as it was. What changes is the point of comparison: after two weeks of living in an open-plan area at 23 °C, a bedroom at 28 °C feels like a deterioration even though nothing has deteriorated.
- Cool air does not rise. Air cooled by a head on the ground floor is denser than the surrounding air. It occupies the lower part of the space and has no physical reason to climb a staircase. The idea that “the cold will spread throughout the house” is the most costly misunderstanding in the entire field.
- With the door open, the effect is real but weak and slow. It depends on air mixing that nothing ensures. An open door does not air-condition a bedroom; it makes it slightly less hot several hours later.
The false remedies
- Lower the setpoints of the served heads. This cools two already comfortable rooms further, increases consumption, and the bedroom remains at the same temperature.
- Blow full force toward the staircase. A jet directed toward a passage serves the room it should serve less effectively, without serving the room it is aimed at.
- Install a fan that pushes cold air upward without a return path. Air movement requires a loop: without a return path, there is no airflow, only noise.
What works reasonably well
- A floor fan placed in the bedroom and aimed toward the door, so that it expels hot air from the room rather than attempting to push cold air into it. The difference is counterintuitive and measurable.
- Manage solar gains: keep the blinds closed during the day on the sunny side, which costs nothing and is often worth more than an additional unit.
- Lower the setpoint in the primary bedroom in the early afternoon rather than at 10 p.m., a principle we have published elsewhere and will not demonstrate again here.
- Most importantly: state it in the quotation, room by room, with an explicit mention of any rooms not served.
Model selected: GWHD(30)ND6MO
Data from the manufacturer's technical sheet (document X610068B):
- Cooling capacity: 8,300 W nominal (28,400 BTU/h), modulated from 2,400 to 10,000 W (8,190 to 34,100 BTU/h)
- Heating capacity: 8,800 W nominal (30,000 BTU/h), modulated from 2,400 to 12,000 W (8,190 to 40,900 BTU/h)
- Efficiency: SEER2 21, HSPF2 10, EER2 12.5, EER 4.00, COP 4.19
- Electrical: 208/230 V, MCA 23 A, maximum overcurrent protection 35 A
- Refrigerant: R32, 2,200 g, add 20 g/m beyond the factory charge
- Piping: 40 m factory charge, 80 m maximum total length, 25 m maximum elevation difference
- Cabinet: 1,020 × 826 × 427 mm, 66 kg — 62 dB(A) at high speed
- Number of connectable indoor units : 2 to 4
- Ranges: -30 to 48 °C in cooling, -30 to 24 °C in heating
- Leak detection A2L integrated, G10 inverter, intelligent defrost, automatic voltage adaptation
- Warranty: 10 years, extended to 12 years with registration with the distributor and proof of installation
The choice between the 24,000 and 30,000 came down to the factory charge (28 m of developed piping versus 30 m on the 24,000, a margin we refuse to consume entirely) and the modulated cooling ceiling, 34,100 BTU/h versus 31,400. The capacity reasoning itself was published in detail elsewhere in this series, and we credit it rather than rewriting it.
The new point: the “number of indoor units” row also has a minimum
The whole series read this row from the top: how many heads at most, and the value of the available port. No one had read the same row from the bottom.
Yet it reads “2”, “2 to 3”, “2 to 4”, “2 to 4”, “2 to 5”. The minimum is never one.
Two practical consequences, and they genuinely come up during appointments:
- A FreeMatch is not the answer for a single room. A customer who wants to cool just one living room should buy a single-zone system, not a crippled multi-zone system.
- A head cannot be removed. The question “could we disconnect the one upstairs since we no longer use it?” has no answer in the manufacturer's table, since the single-indoor-unit configuration is not listed there. The decision to serve two rooms is therefore structural, and all the more reason to make it carefully rather than over the phone.
What the available ports actually allow
This GWHD(30) accepts two to four heads; two are in use. The available ports are real, but the true ceiling is not the number of ports—it is the modulated capacity. The arithmetic we consistently apply before promising a future zone: adding a 9,000 BTU/h head would bring the system to 36,000 BTU/h installed, or about 106% of the 34,100 modulated maximum in cooling—technically defensible if the new zone does not call at the same time as the other two, but something to verify, not promise. Two more heads would clearly push the calculation over the line. The method, applied to the completed system rather than today's configuration, belongs on our Oka page, and here we simply carry it out.
The total length must also be considered: a maximum of 80 m for this model, with 28 m already used. The piping allowance is shared among all current and future branches.
What we write in the quote
- The two rooms served, identified by name, along with the capacity of their indoor units.
- The list of unserved rooms, also identified by name.
- The placement of the outdoor unit and the nature of its support.
- The developed lengths per branch and the amount of refrigerant added, if applicable — here, none.
- The AHRI codes for the combination actually installed, which will be required for the rebate application.
- The exact scope of the wall-penetration finishing work.
Rebates
An efficient heat pump can provide access to programs such as LogisVert and Rénoclimat. Incentives intended for converting a fossil-fuel system do not apply to a fully electric home. Eligibility is determined when the application is opened, using the AHRI code for the installed configuration; we do not publish any amounts, as the rates change independently of us.
Saint-Bruno-de-Montarville and the South Shore
Saint-Bruno-de-Montarville has approximately 26,700 residents across 43.2 km², on the southern slope of Mount Saint-Bruno, one of the Monteregian Hills, within the Longueuil agglomeration. Much of this territory is undeveloped, and the residential stock is concentrated in suburban neighborhoods where brick facades predominate — precisely what gives the first part of this article its local relevance.
At AirGreen, we carry out HVAC installation and HVAC maintenance projects in Saint-Bruno-de-Montarville, Longueuil, Boucherville, Saint-Basile-le-Grand, Sainte-Julie, and Saint-Hubert, as well as in Montreal, Laval, on the North Shore, and throughout the South Shore. Every wall-mounted heat pump project begins with a technical visit: the type of wall, what it can actually support, the routing, and the rooms to be served are determined on site.