R-32 performance and careful execution on a flat roof: an AirGreen project designed to last
Customer context and choice of equipment
In Rosemont–La Petite-Patrie, a plex owner wants to stabilize the comfort of a two-story apartment while reducing energy costs. We recommend a Sharp Eco Inverter wall-mounted heat pump with R-32 (A2L) refrigerant , a compact, efficient solution suited to the neighborhood's typical flat roofs. The chosen unit provides reliable heating in cold weather while ensuring quiet cooling in the summer. The integrated Plasmacluster technology improves indoor air quality, a valued feature in high-occupancy Montreal homes.
Outdoor installation: stability, accessibility and compliance
The outdoor unit is installed on an aluminum support fixed to wooden joists, placed on the flat roof . This configuration:
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guarantees proper clearances around the blower grille to optimize heat exchange;
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reduces the transmission of vibrations to the structure thanks to anti-vibration pads;
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facilitates HVAC maintenance and winter defrosting.
We position a cut-off box in the immediate vicinity, in accordance with current electrical practices, in order to secure service interventions.
Refrigerant and electrical connections: precision and cleanliness
The refrigerant lines (liquid and gas) are continuously insulated with high-density insulation, protected at the support points, and carefully bent to prevent throttling. The flare fittings are calibrated to the correct torque and then checked using an electronic detector. The power and communication cables follow the same route, secured to the structure without abrasive contact with the roof membrane.
For lasting performance, we follow a rigorous protocol:
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Nitrogen test to check the tightness of the circuit.
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Deep vacuum to remove residual moisture.
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Instrumented commissioning with manifolds and thermometry to confirm superheating and subcooling in accordance with manufacturer ranges.
Result: a clean , quiet installation ready to deliver its nominal output.
Why R-32 matters in Greater Montreal
R-32 (class A2L) has a high volumetric capacity and a lower GWP than R-410A, which contributes to better seasonal efficiencies. Used on recent heat pumps , it promotes:
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stable performance in low temperature heating;
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more contained refrigerant charges;
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simplified maintenance thanks to clearly established procedures.
Our teams are trained in A2L best practices (ventilation, absence of sparks, leak testing) in order to protect occupants and technicians.
Interior: targeted comfort and sound discretion
The wall-mounted airhead, positioned on a central load-bearing wall, supplies the main living area and a hallway. Motorized shutters distribute the air to limit cold spots, while the heating mode maintains a gentle, continuous flow. We fine-tune:
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the blowing temperature for immediate comfort;
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defrosting instructions adapted to Montreal winters;
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ventilation levels for pleasant acoustics , including at night.
Condensate management: four-season reliability
The condensate drain follows a gravity path to the exterior with a controlled slope. In configurations where gravity is not possible, we integrate a lifting pump with a flow barrier, but here, the installation allowed for a natural, more reliable and quieter flow. All connections are insulated to prevent internal condensation during the summer.
Construction site challenges and solutions
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Flat roof and membrane : systematic protection under each support point, paths without sharp edges, sealing of crossings with compatible materials.
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Sun exposure : orientation of the condenser to limit the recirculation of hot air and preserve efficiency.
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Service access : safe working height, valve side clearance and technical labels for future operations.
What the customer gains on a daily basis
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Stable comfort in summer and winter, without disturbing noise on the terrace;
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Energy savings thanks to the inverter and good seasonal settings;
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Improved air quality via Plasmacluster;
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Peace of mind : HVAC installation compliant, documented, and covered by our labor warranty.
Grants and procedures
Depending on the selected capacity and low-temperature performance, the equipment may be eligible for energy efficiency support programs . We assist our clients in Montreal, Laval, Longueuil, the North Shore, and the South Shore to verify eligibility, gather proof of installation, and optimize the application.
Recommended maintenance: the key to performance
To preserve yields:
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Cleaning of internal filters every 4–8 weeks in season;
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Annual inspection : exchanger, fans, electrical tightening, leak tests, parameter updates;
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Winter clearance around the outdoor unit (ice/snow) to maintain free airflow.
Our HVAC maintenance contracts cover these operations and prioritize interventions before heat or cold peaks.
Best practices to remember for a flat roof in Rosemont
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Choose a strong, corrosion-resistant support structure that is compatible with the distributed load of the roof;
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Place a visible and accessible cut-off box ;
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Protect line insulation against UV;
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Avoid sharp bends and adhere to recommended linear lengths to ensure capacity;
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Plan for snow removal and safe service access .
Why AirGreen for your project in Rosemont–La Petite-Patrie
Our teams work weekly on R-32 wall-mounted heat pumps in Greater Montreal . We understand the constraints of flat-roofed plexes, urban schedules, and tight access. Each project is documented , photographed, and delivered with commissioning measurements —a guarantee of performance and transparency.
Frequently Asked Questions
What power (BTU) should I choose?
Power depends on volume , insulation and solar orientation. We carry out room-by-room sizing to aim for a balance between comfort, acoustics and consumption.
What if I want to add a second room later?
The single-zone wall-mounted solution can be supplemented with a second dedicated unit. For multiple needs from the outset, a Multi-Zone Heat Pump can be considered; we evaluate the most appropriate option based on the layout of the home.
How long does it take to install?
For a similar configuration (flat roof, short route, adjacent power outage), the intervention is generally carried out in one day , including tests, subject to weather and access conditions.
Conclusion
This HVAC installation in Rosemont–La Petite-Patrie illustrates the AirGreen approach: advice , precise execution and instrumented commissioning . The Sharp Eco Inverter R-32 wall-mounted heat pump offers a winning combination: comfort, discretion and low operating costs – a sure value for homes in Greater Montreal .
Need a free estimate in Montreal, Laval, Longueuil, the North Shore, or the South Shore? Our experts will visit your site, confirm the power, and provide you with a clear proposal, ready for potential grant applications.