Installation of a 5-head GREE FreeMatch R32 multi-zone heat pump (GWHD(42)ND6MO) in Pointe-des-Cascades, Vaudreuil-Soulanges RCM

Cooling a food-service premises: five zones at the entrance to the Soulanges Canal

This Pointe-des-Cascades project is not a house. The photo says so in three details: a suspended ceiling with exposed framing and round recessed lights, a white raceway running along the wall to the GREE wall-mounted head, and, at the bottom of the frame, a stack of disposable cups in front of a glass-front refrigerated display case.

This is a food-service commercial premises, near the entrance to the Soulanges Canal and Parc des Ancres, in a village where a large share of traffic is concentrated between June and September. This combination—cooking, refrigeration, seasonal customers, and hygiene requirements—overturns several of the rules we apply in residential settings.

This is the fourth non-residential project in this series, after an office in Sainte-Julie, a community building in L'Île-Perrot, and a service business in Pointe-Fortune, and the first in food service.

The load of a food-service premises does not come from the building envelope

In a house, the cooling load comes from the sun, windows, and insulation. In a food-service premises, it comes from inside, and it never stops.

Three sources dominate, and none appears on an architect's plan:

• Refrigeration releases its heat into the room. Every refrigerated display case, chest freezer, and ice machine has a condenser, and that condenser releases into the premises exactly the heat it removes from its contents, plus the heat from its own motor. A business that adds a second display case adds a permanent cooling load, twelve months a year.
• Customers. A food-service operation concentrates occupants in a small area, with rapid turnover, each person contributing sensible heat and moisture.
• Lighting and countertop appliances — toasters, countertop ovens, warming plates, coffee makers.

The consequence is counterintuitive for a business owner: the premises may call for cooling in November, while the house next door is being heated. This is also what makes a modulating multi-zone system particularly well suited here, since it can handle a small cooling load during the cold season—something a fixed-speed unit does very poorly.

We had published similar reasoning for an office in Sainte-Julie. The difference in food service lies in the refrigeration, which is absent from an office and turns an intermittent occupancy load into a permanent load.

The kitchen hood puts the room under negative pressure

This is the point most often overlooked in commercial air-conditioning quotes, and it alone can cause a perfectly sized system to fail.

A commercial hood exhausts a substantial volume of air. That air must be replaced. If there is no dedicated make-up air supply, or if it is insufficient, the room goes into negative pressure and draws air through every available air leak: under the doors, through the entrance door that opens for each customer, and around pipe penetrations.

What this does to a wall-mounted heat pump:

1. It is constantly fighting untreated outdoor air — 30 °C and humid in July, -15 °C in January.
2. The actual load becomes much higher than the load calculated from the building envelope, and the head appears undersized even though it is not.
3. Cold drafts appear at floor level, near the doors, exactly where customers are seated.

Our position on this type of project: the make-up air supply must be validated before sizing the heads, together with the ventilation contractor and the owner. An air-conditioning unit does not replace a ventilation system, and a wall-mounted heat pump introduces no outdoor air — it recirculates the room air through a coil. We stated this principle in a residential context in our Beauharnois article; in food service, it is no longer merely a comfort consideration, but a condition for proper operation.

This is also why the cooking area beneath the hood did not receive a head. A comfort appliance installed within the field of a commercial hood, in air laden with greasy aerosols and subject to constant negative pressure, quickly becomes dirty and operates poorly.

Sizing: refrigeration decides, not floor area

A business in which all zones are occupied at the same time is not sized like a house. We developed this reasoning — the diversity factor collapses as soon as simultaneity is complete — in our Pointe-Fortune article, for a service business in the same regional county municipality. The principle applies fully here: at noon, all five zones call for heating or cooling together.

The installed allocation therefore totals 36,000 BTU/h, or 86% of the nominal cooling capacity of the GWHD(42)ND6MO and approximately 81% of its maximum modulating capacity of 44,300 BTU/h. This is the lowest ratio we have published in this series, and it means one simple thing: the compressor can supply all five heads at full capacity simultaneously, with room to spare.

What is specific to this project is how the capacities are distributed among the zones. It was not the floor area that decided the matter, but the location of the refrigeration equipment:

The counter area occupies a modest floor space yet receives the same capacity as the front room, which is twice as large. A calculation based on square footage would have produced the opposite result, and the person working eight hours behind that counter would have paid the price.

The trade-off must be acknowledged. A closed premises on a Tuesday in November requires very little, and a single small zone calling for cooling on its own can drop below the system's modulation floor, 8,870 BTU/h, resulting in short-cycling—the mechanism discussed in our Saint-Chrysostome article. The free solution: during the off-season, leave two zones running instead of just one.

The opposite approach—installing five 12,000 BTU/h units “just to be sure”—would have produced five oversized appliances that short-cycle outside peak hours, dehumidify poorly, and make noise in a room where people talk.

Where not to blow air in a food-service area

Positioning a unit in a space where food is handled involves constraints that exist nowhere else.

• Never blow air directly onto a preparation surface, uncovered food, or a handwashing station. An air stream moves particles, and a comfort appliance is not filtration equipment.
• The condensate drain must never run above a work surface, preparation counter, or open piece of equipment. An overflow above a food counter is not a stain on the wall; it is a health incident.
• Everything we install must remain cleanable and accessible. A wall-mounted unit and its line-hide form a horizontal surface high up that collects dust and aerosols. It must be possible to wipe it down without dismantling anything.
• The maintenance frequency is not the same as in a residence. Here, we recommend cleaning the filters much more frequently than at home, along with thorough coil cleaning by a technician at short intervals. Greasy aerosol buildup also occurs in the dining area, not just in the kitchen—we developed this point in our Saint-Stanislas-de-Kostka article, for an open residential kitchen.

Blowing on a refrigerated display case

The glass-fronted display case visible at the bottom of the photo deserves its own rule. A comfort-air jet directed toward a refrigerated display case produces two effects, both undesirable:

• The display case load increases. Air moving against its walls and air curtain accelerates its heat exchange with the room, its compressor runs more often, and it rejects even more heat into the space—the snake biting its own tail.
• Condensation appears on the glazing when warm, humid air is actively pushed against a cold surface.

The unit was therefore oriented to sweep across the room without aiming at the display case, and the air-discharge louvers were adjusted accordingly during commissioning.

Everything is visible, everything must be cleaned: exposed conduit and suspended ceiling

The second lesson from this project is evident in what the photo shows without saying: nothing is hidden. The conduit is exposed, it meets the suspended ceiling, and a white pipe runs upward to the right of the unit.

Why we did not hide the piping in the ceiling void

A suspended ceiling offers a tempting service space, and we use it regularly—that is exactly what we did in the Sainte-Julie office. In a food-service space, the reasoning is reversed for three reasons:

1. A ceiling void is an inaccessible space. Anything that gets dirty in it cannot be cleaned, and anything that leaks there cannot be seen. Surface-mounted conduit can be wiped with a cloth and removed with a screwdriver.
2. Inspection is immediate. A trace of moisture on exposed conduit is spotted in passing; the same trace above the ceiling tiles is discovered when a tile becomes stained—which is too late.
3. A suspended ceiling grid is not a load-bearing structure. Any piping that passes through this space must be supported independently of the grid, from the slab or structural framework, and never suspended from the T-grid.

The choice of exposed conduit is therefore an operational decision, not an aesthetic compromise. We announce it before the work begins, because visible conduit is always a surprise when it has not been mentioned.

The point that almost no one checks: is the ceiling void a return-air plenum?

In many commercial buildings, the space above the ceiling tiles is not just used to hide pipes: it serves as a return-air plenum for the ventilation system. Air from the room rises into it, circulates, and returns to the air-handling unit.

This completely changes the status of what is installed there. In a return-air plenum, exposed materials are subject to requirements for flame spread and smoke developed—which is why communication cables sold for these spaces carry a specific designation.

However, a refrigerant line set is insulated with combustible elastomeric foam. Running a set of insulated lines through a return-air plenum without verifying its status is a silent error: it is not apparent during commissioning or the first winter, but it emerges during an inspection or insurance renewal.

Our method:

• Ask the owner and the ventilation contractor before choosing the route: is this void a return-air plenum, or simply a service void?
• If it is a plenum, favor a surface-mounted route in a cable tray beneath the ceiling—which is exactly what was done here—or use materials rated for this application.
• Never solve the problem by cutting the insulation where it passes through. An uninsulated suction line in an air-conditioning system will condense and cause water to drip where no one can see it. We documented this mechanism in our articles on Saint-Étienne-de-Beauharnois and Saint-Louis-de-Gonzague.

The rising drain

The white pipe running upward on the right side of the unit indicates that gravity drainage was not available and that a condensate pump was installed to reach a higher drain point—a common situation in commercial premises, where the drain connects to an existing network at ceiling level.

We covered the drain design of a five-zone system in detail in our Cèdres article, so we will not revisit it here. However, two requirements specific to food-service environments apply:

• The float safety switch is non-negotiable and must stop the associated head, not merely trigger an alarm. In a food-service business, an overflow above a counter can interrupt service.
• The pump reservoir belongs on the maintenance schedule. This is exactly where biofilm forms, and in a food-service space, this buildup manifests as an odor well before it causes a breakdown.

Mistakes to avoid when air-conditioning a commercial food-service space

• Size by floor area. Two identical premises do not have the same load if one has three refrigerated display cases and the other has none.
• Apply a residential diversity factor to a business where all areas are occupied at the same time.
• Ignore the hood and makeup air. This is the leading cause of commercial systems being deemed “undersized” when they are actually adequate.
• Place a head within the field of a cooking hood.
• Direct the supply air toward a refrigerated display case or a food-preparation surface.
• Run insulated lines through a return-air plenum without verifying the status of that space.
• Apply a residential maintenance schedule to a unit operating twelve hours a day in heavily polluted air.
• Schedule the work during the busy season. Installation takes place outside peak periods, and commissioning is performed with the premises empty.

The figures that drove the decisions

The GWHD(42)ND6MO is the only unit in the FreeMatch R32 range that accepts five indoor units; the model was therefore determined before any calculations, as we explained in our Sainte-Martine article. The ratio between the modulation floor and maximum capacity is the decisive figure here because it precisely defines the difference between a November Tuesday and a July Saturday.

Financial assistance: the commercial program is not the residential program

LogisVert, Rénoclimat, and Chauffez vert are intended for the residential sector. A business does not qualify simply because a residential unit has been installed in a commercial space.

For a commercial building, financing generally goes through Hydro-Québec's energy-efficiency programs for businesses and government programs such as ÉcoPerformance, whose criteria and terms differ completely from those for residential properties—the same approach used for the Sainte-Julie office and the L'Île-Perrot community building. We assess eligibility on a case-by-case basis, supported by detailed invoices and the AHRI certification for the actual combination installed, before promising anything to a business customer.

AirGreen in Pointe-des-Cascades, Vaudreuil-Soulanges, and Montreal

Pointe-des-Cascades occupies the point where the Ottawa River meets the St. Lawrence River, at the entrance to the Soulanges Canal, in the Vaudreuil-Soulanges RCM, about thirty minutes west of Montreal. We regularly serve this area: Les Cèdres, Les Coteaux, Coteau-du-Lac, Vaudreuil-Dorion, and L'Île-Perrot.

At AirGreen, we install wall-mounted heat pumps, central heat pumps, air conditioners, and air exchangers for homeowners and businesses in Montreal, Laval, Longueuil, the North Shore, and the South Shore. A commercial space is assessed on-site, appliance by appliance, including the hood, before a model is recommended.