Two independent zones, finely modulated performance and exemplary exterior installation
At AirGreen , we design HVAC systems that respect the architectural reality of Montreal plexes while maximizing seasonal performance. In this Villeray–Saint-Michel–Parc-Extension residence, we installed two Sharp wall-mounted heat pumps operating in an independent single zone . The goal: to cool and heat two separate living spaces with precise modulation, a contained noise level and simplified maintenance.
The neighborhood's typical brick facade, the small footprint, and the need for powder- and snow-proof clearance guide our choices: wall bracket mounting , calculated height above the gravel, dedicated disconnect boxes , and rigorous condensate management . The result: a robust, aesthetic, and durable installation, designed for the climate of Greater Montreal .
Context and choice of system
The owner wanted independent control for two zones: a living area on the ground floor and a bedroom upstairs. Rather than a single multi-zone system, we opted for two Sharp single-zone systems . This approach offers concrete advantages:
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Redundancy : If one unit requires maintenance, the other continues to provide comfort.
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Optimized efficiency : each inverter compressor works exactly on the thermal load of “its” room, limiting hydraulic and refrigeration compromises.
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Flexibility of use : different times and instructions depending on actual occupancy.
The Sharp Eco Inverter range is chosen for its extended modulation , quiet operation and Plasmacluster Ion air purification functions on the indoor heads, useful for reducing odors and fine particles.
Outdoor installation: ventilation, snow and acoustics
Positioning. The two condensers are offset from each other to prevent hot air from transferring between units and to facilitate circulation around each unit. The side discharge has a free field, which stabilizes pressure and subcooling even during summer peaks.
Elevation on brackets. We use galvanized brackets with anti-vibration pads (visible blue shims) to decouple vibrations from the masonry. This elevation meets three requirements:
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Clear ventilation vents of dust and blown snow;
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Facilitate snow removal and spring runoff;
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Limit acoustic transmission towards the interior.
Standard clearances. Distances from the wall, floor, and between appliances are checked to ensure maintenance and performance in defrost mode. Cables and refrigeration connections follow compliant bending radii , avoiding pressure drops and fatigue points.
Power supply and protections
Each unit has its own waterproof outdoor disconnect box , positioned within easy reach in accordance with the requirements of the Quebec Electrical Code . The circuits are dedicated from the panel, with circuit breakers adapted to the plate current. The cable trays are sheathed and sealed at the penetration to prevent water and stray air infiltration into the building envelope.
Refrigeration path and condensate management
Our teams favor short lines : the crossing is made directly behind each indoor unit to minimize the length of copper and therefore losses, stabilize the refrigerant load and optimize the response of the Inverter .
Condensates (summer). The drains are gravity-fed , with a continuous slope to the discharge point. This choice eliminates the lifting pump, reduces noise and simplifies maintenance . The external outlets are protected by non-return fittings and remain clear of gravel.
Defrosting (winter). The space under the appliances and the granularity of the stone bed promote the evacuation of defrost water during freeze/thaw periods—a crucial detail to prevent ice from forming under the unit.
Sizing and comfort: aim right, last long
Sizing is established room by room based on actual thermal loads (orientation, glazing/wall ratio, airtightness, air infiltration, floors). In this configuration, the 12,000–15,000 BTU/h range per zone is generally the most consistent.
Why avoid oversizing:
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short cycles, premature compressor wear ;
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degraded dehumidification in summer;
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unnecessary noise and seasonal efficiency losses.
The Sharp Inverter finely modulates the power to maintain the setpoint without oscillation, with contained electricity consumption over the year.
AirGreen commissioning: the method that secures performance
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Nitrogen leak tests and deep vacuum until stabilization to the micron.
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Valve opening , balancing and superheat/subcooling control.
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Electrical checks (tightening torques, voltage drop, continuity).
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Calibration of remote controls and air sweeps adapted to the geometry of the rooms.
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Customer file : installation photos, serial numbers, parameters, HVAC maintenance schedule.
Air quality and Plasmacluster functions
Sharp wall heads incorporate Plasmacluster Ion technology. Combined with regular filtering , it helps reduce airborne dust and cooking odors. We recommend:
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cleaning filters every 4 to 8 weeks during peak season;
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annual inspection: coil, tank, turbine, electrical tightening, updating of seals;
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maintaining clearance in front of the units to preserve the air flow and dehumidification .
Montreal winter: best practices
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Install a snow protection roof when the site is very exposed to falling roofs;
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Do not obstruct the blowing with improvised protections: ventilation remains a priority;
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Keep 20–30 cm free under the appliance for defrost water to drain away;
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Activate intelligent defrosting via manufacturer logic and keep the facade free of accumulation .
Why two single zones rather than one multi-zone here?
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Efficiency : each zone has its own load curve ; single zones avoid using a common compressor at very low partial load.
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Maintenance cost : standardized components, faster diagnostics.
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Acoustics : Two smaller, slow-rotating fans remain very discreet and allow the unit to be turned off in an unoccupied area.
Grants, Compliance and Warranty
Recent high-efficiency wall-mounted heat pumps may be eligible for provincial programs (e.g., Rénoclimat , Chauffez vert ), subject to certified performance and housing configuration. Our team supports:
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technical documentation (models, serial numbers, tests);
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standard photos ;
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installation certificate and advice on how to maximize incentives .
Code compliance and proper installation preserve the manufacturer's warranty and the owner's peace of mind .
Common mistakes… and how to avoid them
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Space the units too little from the ground : we dimension the height against snow and for maintenance.
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Refrigerated routes too long : we favor direct crossings to maintain efficiency.
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No disconnection box : here, each unit has its own dedicated protection .
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Visual alignment : laser leveling, regular center distances, stainless steel fixings — a clean and durable finish on brick.
Conclusion: four-season comfort and flexibility of use
The Sharp + AirGreen installation combination provides rapid cooling in summer, reliable heating support in spring and fall, and controlled energy bills. The two independently controlled zones adapt to the real pace of life : teleworking, guest rooms, unoccupied rooms.
Our teams operate in Montreal , Laval , Longueuil , on the North Shore and the South Shore , with the same level of requirement: precise diagnosis , impeccable aesthetics and performance measured over time.
HVAC Maintenance – Owner Memo
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Check and clean filters (4–8 weeks with heavy use).
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Maintain a clear perimeter around condensers.
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Plan an annual visit (waterproofing, parameters, exchangers, electricity).
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In winter: monitor the defrost water drainage and keep the stone bed free.