A discreet and efficient upgrade for a Plateau plex, with a flat-roof condenser designed for the Montreal climate and simplified maintenance.
Context: a Plateau plex that requires comfort, silence and discretion
In Plateau-Mont-Royal , flat-roofed brick buildings pose very real constraints: limited outdoor space, close-knit neighborhoods, busy alleyways, and strict noise requirements. Here, we are installing a Gree heat pump from the Clivia R32 range in a single-zone configuration to efficiently cool and heat a 4.5-bedroom apartment, while preserving the aesthetics of the facade. The condenser is installed on the flat roof to avoid cluttering the courtyard and reduce sound transmission to neighboring units.
Performance objectives
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Maintain a stable temperature in summer and winter, with optimized performance thanks to R-32 refrigerant .
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Reduce noise pollution by placing the condenser high up and using anti-vibration supports .
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Facilitate seasonal maintenance with clear access, mechanical coil protection and a clean and durable connection route.
Study and sizing: load above all
Before any HVAC installation , our team performs a sizing based on the surface area, orientation, airtightness and occupancy habits. On this project, the target capacity range is in the 9–12 kBTU range for an open living room forming an “L”. This choice favors:
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Sufficient airflow to sweep the main area without localized drafts.
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Precise modulation at low speed to maintain silence, essential in a dense neighborhood.
Why Gree's Clivia R32 range?
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R-32 : Better heat transfer and reduced load compared to R-410A, with reduced warming potential.
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Inverter modulation : maintaining comfort without over-consumption.
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Cold weather behavior : smart defrost cycles, useful during Montreal and North Shore winters.
Flat roof installation: stability, longevity and safety
Supporting and anti-vibration structure
The condenser rests on a galvanized steel frame placed on treated wooden soles with anti-vibration pads . This configuration:
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Diffuses the charge and protects the roof covering .
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Reduces vibration transmission to the interior structure.
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Ensures uniform clearance around the condenser: 30 cm on the sides and 60 cm on the front for air flow.
Coil protection and ventilation
The blue finned coil is protected by a mechanically welded grille . Advantages:
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Prevention of accidental impacts during maintenance passages.
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Maintains a regular airflow, limiting obstructions by leaves or debris.
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Sober and durable aesthetics in the sun and thermal variations.
Wind and snow management
On the Plateau rooftops, wind can be strong. We orient the unit so that the rear is partially sheltered by a technical wall, while keeping the blower flap clear. In winter, accumulated snow is rarely a major problem on this type of raised support, but we provide sufficient vertical clearance to ensure defrosting remains effective.
Refrigeration path: cleanliness, slope and sealing
Route of the connections
The refrigeration lines (insulated annealed copper), the communication cable and the condensate drain descend from the roof through a sealed passage (flashing, vapor barrier, polyurethane sealant) to the interior service shaft. The exterior sections are sheathed and UV-taped to resist rays and freezing/thawing.
Best practices implemented:
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Brazing under nitrogen to avoid internal oxidation.
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Leak test with dry nitrogen (high pressure) then vacuum up to 500 microns with vacuum holding.
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Compliance with oil slopes and total length recommendations (reducing pressure losses).
Condensate drainage
Summer air conditioning requires reliable drainage. Here, gravity drainage to an indoor collection point was preferred. When gravity isn't available, we integrate a quiet condensate pump with a safety float switch; this was not required on this project.
Power supply and safety
We install an external disconnect switch adjacent to the condenser for isolation during work, in accordance with the Code. The dedicated line is sized according to the machine's nominal current and protected at the panel. Penetrations are sealed and marked. This approach reduces the risk of moisture in the duct and makes it easier to read during maintenance.
Result: four-season comfort and absolute discretion
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Summer comfort : the living room quickly reaches the set point, the speed of the interior fan stabilizes, limiting noise variations.
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Mid-season and mild winter heating support : the heat pump provides most of the heating needs, leaving the backup system (if present) to intervene only in very cold weather.
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Silence : the rooftop location and anti-vibration pads minimize propagation to neighboring homes.
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Aesthetics : no visible projection on the street facade - a plus in a heritage district.
Preventive maintenance: the key to lasting performance
Periodic HVAC maintenance ensures seasonal performance and component longevity.
What we do during an annual visit
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Cleaning of the condenser (panels, grille, fins) and inspection of the connections .
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Checking operating parameters (intensity, overheating/subcooling depending on context, temperature readings).
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Checking drainage , external insulation and UV tape resistance.
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Updated the checklist for customer follow-up.
What the customer can do
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Maintain 1 m clear in front of the condenser (bags, leaves, temporary equipment).
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Gently clean the inner head filters every 4 to 8 weeks.
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Monitor the controller codes and contact us if there is any abnormality.
Practical advice for flat roofs on the Plateau
Choice of support
A raised four-point support prevents puddles and facilitates roof drainage. The bolts are stainless steel and re-torqued after the first season.
Minimalist Path
In plexes, the best route is often roof → technical shaft → living room . This limits lateral openings in the brick and preserves the character. The exterior hoods — if they are visible — are chosen in a neutral color to blend in with the woodwork.
Winter
During a frost episode, allow the unit to complete its defrost cycle . Avoid accumulating light objects near the blower that could be sucked in.
Grants and Eligibility
High-efficiency wall-mounted heat pumps with R-32 refrigerant are generally eligible for various programs in effect depending on the municipality and level of government. Our team will guide you on files covering Montreal , Laval , Longueuil , the North Shore and the South Shore , ensuring:
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Check low temperature performance and product registration on recognized lists.
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Prepare the necessary documents (detailed invoice, photos, serial numbers).
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Respect the application deadlines after installation.
What sets AirGreen apart in this type of intervention?
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Rigorous methodology : load calculation, instrumented commissioning, installation report.
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Respect for the building : limited drilling, careful sealing, preserved aesthetics.
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Service : support for HVAC maintenance , seasonal reminders and availability during hot weather.
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Local coverage : rapid intervention in Montreal , Laval , Longueuil , North Shore and South Shore with internal teams.
Frequently Asked Questions (and Our Answers)
Noise perceived by neighbors
The roof -mounted mounting and skids reduce transmission. Inverter modulation prevents high revs.
Lifespan of exposed roof equipment
The coil protection grid , stainless steel screws and annual maintenance limit corrosion and deformation.
Roof waterproofing
We entrust the waterproofing restoration to materials compatible with the existing membrane, with appropriate flashing and sealant. A visual inspection is planned at 12 months.
Heating capacity in intense cold
We design to cover the mid-season and mild winter. In very cold weather, a backup can be added depending on the building's envelope—it's an energy-efficient strategy that maximizes the COP over the year.
Conclusion: tailor-made comfort, designed for the Plateau
This HVAC system combines visual simplicity , energy efficiency , and simplified maintenance . The Gree Clivia R32 fits perfectly into the rhythm of a Plateau-Mont-Royal plex: cool in the summer, gentle heat in the winter, and a discreet condenser that respects the neighborhood. For a similar project in Montreal , Laval , Longueuil , the North Shore , or the South Shore , our team offers a comprehensive approach: study, installation, maintenance , and support for subsidies — a smooth path to lasting comfort.