A typical Montreal construction site: flat membrane roof, rear staircase access and tree-lined courtyard. We are installing a Sharp ZU1 (R-32) wall-mounted heat pump , designed to deliver four-season comfort without sacrificing the occupants' peace of mind or the integrity of the roof. The result: a high-performance, quiet and durable HVAC solution, perfectly integrated into the built environment of Mercier–Hochelaga-Maisonneuve .
A calibrated solution for Montreal plexes
The client's objectives
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Efficient air conditioning in the main living area and reliable heating support in winter.
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Discreet installation , without unnecessary drilling into the roof and with minimal noise pollution on the courtyard side.
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Simple and safe HVAC maintenance , given roof access.
Why the Sharp ZU1 (R-32) ?
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High-efficiency inverter compressor: stable performance in very cold conditions and fine speed modulation.
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R-32 refrigerant: better energy efficiency and lower GWP compared to R-410A.
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Improved indoor air quality (brand-specific filtration/ionization technology) and very low noise level from both units.
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Typical capacity range 12k to 18k BTU, suitable for open areas of Montreal apartments.
Flat roof HVAC installation details
Membrane support and protection
On the roof, we place the condenser on a raised aluminum structure , separated by anti-vibration pads . The whole thing rests on distribution soles and treated wooden beams , in order to distribute the loads and preserve the membrane .
No perforating anchors are required: stability comes from the ballast and the geometry of the support, in accordance with current practices on elastomeric roofs.
Heights and clearances :
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Condenser elevation ~30–40 cm to prevent snow build-up and allow frost to drain during defrosting.
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Front clearance > 60 cm to ensure air intake and maintenance access; side and rear clearance respected according to the manufacturer's recommendations.
Refrigerated and electrical routes
The refrigeration lines run in a short, direct path between the indoor head and the condenser. The pipes are continuously insulated , protected in UV capping and securely clamped to resist wind.
On the power supply side, an external disconnect (proximity cut-off) is installed within sight of the condenser, on a support adapted to the roof conditions, and connected to the circuit breaker dedicated to the housing's electrical panel.
Condensate and defrost management
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In summer , the condensate from the interior head is drained by gravity via a controlled slope to the exterior.
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In winter , the area under the condenser remains free to receive defrost water, avoiding ice cubes on the facade. If necessary, we provide a deflector or a seasonal drip pan when the configuration requires it.
Acoustic precautions
We combine silent blocks , precise fan adjustment and condenser orientation to limit any sound reflection towards neighboring windows. The Sharp ZU1 's inverter operation reduces on/off cycles and significantly reduces noise perceptible in the courtyard.
Rigorous commissioning
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Calibrated flares and tightening to the correct torque .
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Nitrogen pressurization and leak test .
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Deep vacuum ≤ 500 microns, stabilization, then opening of the fluid.
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Electrical (intensities), thermodynamic (overheating/subcooling) checks and verification of fan rotation direction .
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Setting modes , air sweeps and instructions with the occupant.
Careful interior integration
The wall-mounted fan head is placed in the living room above an opening, providing efficient sweeping and avoiding direct blowing onto people. The positioning limits the length of the lines (≈ 2–3 m), which improves the actual COP and accelerates the temperature rise in heating mode.
Performance, comfort and savings
Summer air conditioning
The airflow moves along the ceiling, mixes, and then descends, ensuring uniform cooling without the sensation of drafts. Inverter modulation maintains a comfortable humidity level .
Heating in the off-season and during severe cold
The Sharp ZU1 holds its own in Montreal winters, reducing consumption compared to baseboards and ensuring a solid backup during cold snaps. The customer gains in thermal stability and silence .
Air quality
Washable filters and ionization technology reduce dust and allergens—an asset in dense neighborhoods. We provide the customer with a simple and precise HVAC maintenance schedule .
What else AirGreen does
Design for real life
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Minimal travel , limited bends and slopes respected : less losses, more useful capacity.
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Perfect sealing at wall penetrations; continuous insulation to prevent any internal condensation .
Roofing: durability and safety
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Choice of membrane-compatible supports , load distribution and dimensioned anti-vibration .
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Route lines away from runoff areas and roof drains .
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Safe access : clear service road to facilitate maintenance visits.
Deadlines and quality
A planned construction site: technical visit, BTU sizing (often 12k–18k for this type of area), procurement, installation in one day and documented commissioning . Each project is delivered with test reports and usage recommendations .
Maintenance and best practices
To be done by the occupant
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Clean filters every 4–6 weeks during use.
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Keep 1 m free in front of the inner head and clear the area around the condenser.
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Use Auto mode with a set point of 22–23°C for optimum comfort.
Annual AirGreen Maintenance
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Electrical and refrigeration inspection;
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Battery/fan cleaning;
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Checking supports , waterproofing and drainage ;
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Update settings if usage changes.
Regular HVAC maintenance maximizes lifespan and warranty .
Grants and support
High-efficiency R-32 wall-mounted heat pumps are generally eligible for assistance programs when performance thresholds are met. We support our clients in Montreal, Laval, Longueuil, the North Shore, and the South Shore to validate eligibility , gather evidence , and optimize the application.
The verdict
This Sharp ZU1 installation in Mercier–Hochelaga-Maisonneuve delivers exactly what was expected: 4-season comfort , silence , controlled consumption and a clean roof integration that respects the membrane and the neighborhood. A project by AirGreen , designed to last — summer and winter.
Are you planning a wall-mounted heat pump installation in Montreal, Laval, Longueuil, on the North Shore or the South Shore?
Our AirGreen experts size, install and maintain your HVAC system with a technical and careful approach adapted to the local architecture.