Context: four-season comfort in a brick plex
In Rosemont–La Petite-Patrie, many red brick plexes have a small rear patio and tight side access. Our client wanted consistent comfort in both summer and winter, without encroaching on circulation space or transmitting vibrations to the structure. We recommended a Sharp wall-mounted heat pump ( ZU1 series, R-32 refrigerant): a modern, efficient choice that's particularly suited to Montreal's urban fabric.
Why the Sharp ZU1 series for Montreal
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Inverter technology to finely modulate power and reduce consumption.
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R-32 refrigerant with lower GWP than R-410A, aligned with new environmental requirements.
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Reliable operation in cold weather, ideal for the Montreal metropolitan area, Laval and the North Shore / South Shore .
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Plasmacluster filtration, a significant asset for indoor air quality.
Summary of the need: quiet air conditioning in summer, efficient additional heating in winter, compact and aesthetic installation, simple maintenance.
What we installed, and how
Outdoor installation designed to last
The Sharp condensing unit sits on a raised, anchored, and perfectly level aluminum stand . We added high-density anti-vibration pads under each leg to mechanically decouple the unit from the structure. This setup provides three major benefits:
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Clearance from the ground for snow and meltwater;
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Reduction of vibration transmissions to masonry;
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Optimized air circulation around the device.
The location, adjacent to the brick wall and a wooden fence, is protected from prevailing winds while maintaining the necessary clearances for suction and blowing. The refrigeration connections and wiring are routed laterally towards the interior, over a short distance (typical "back-to-back" configuration), which limits pressure losses and improves the system's responsiveness.
Refrigeration connections and power supply
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HVAC quality insulated copper refrigeration tubing with controlled bend radii;
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Sealing achieved by calibrated flaring and tightening torques using a torquemeter ;
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Deep vacuum before opening the valves, then leak test;
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Dedicated power supply with Canadian Electrical Code compliant circuit breaker and frost protection for wiring.
Condensate management and winter protection
Winter defrosting causes water to accumulate; elevating the condenser above the patio floor prevents water from accumulating under the unit. The support also facilitates seasonal cleaning. The front of the unit remains clear for maintenance—a crucial point for any residential HVAC installation in Montreal.
Simplified load study and capacity selection
In a typical Rosemont plex, a living space of 500 to 800 sq ft per floor generally requires 9,000 to 15,000 BTU of cooling depending on exposure, insulation and solar gain. The ZU1 series covers these needs with sizes of 12k, 15k, 18k and 24k BTU. We adjust the capacity after validating the glass surfaces, infiltration rates and the actual use of the rooms. The inverter approach then allows us to refine the power delivered to maintain a stable temperature and an excellent humidity level .
Site challenges… and our solutions
1) Limited rear space
Rosemont backyards leave little room for space. The compact raised support allowed us to maintain regulatory distances while preserving the path to the patio door.
2) Perceived vibrations and noise
For old masonry brick walls, the structural spread can be surprising. The combination of anti-vibration pads + torque tightening + fan imbalance check ensures quiet operation for occupants and neighbors.
3) Bad weather and freeze/thaw cycles
Positioning away from snow accumulation areas, setting the height above the level of normal accumulations and the orientation of the blowing ensure efficient defrosting and increased longevity.
Result: comfort, energy efficiency and controlled aesthetics
After commissioning (checking the currents, evaporation/condensation temperatures and overheating), the Sharp ZU1 heat pump delivers consistent cool air in summer, with a gentle increase in power and long cycles at low noise levels. In mid-season and winter, the machine provides economical supplemental heating , reducing the use of electric baseboards. The facade remains discreet : the condenser blends neatly into the brick/wood decor, with no visible cables or overflows.
AirGreen Best Practices for Montreal Homes and Plexes
Choosing the outdoor location
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Choose a clear area (free air intake/expulsion).
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Avoid enclosed spaces that recycle hot air in summer.
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Provide a raised base or brackets depending on the configuration of the building.
Select capacity
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Take into account the orientation, glazing and actual insulation;
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Oversizing is detrimental to comfort (short cycles, poorly managed humidity); undersizing tires the compressor.
Healing the connections
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Short lengths, wide curves, continuous insulation ;
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Leak tests and deep vacuum are mandatory before any fluid release.
Think about HVAC maintenance
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Cleaning the filters on the indoor unit side at the start of each season;
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Gentle rinsing of the external battery (without high pressure);
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Annual HVAC maintenance visit recommended to maintain performance.
Energy subsidies and savings
Recent R-32 wall-mounted heat pumps , high efficiency and designed for extreme cold , may be eligible for certain assistance programs when technical criteria are met (seasonal efficiencies, certification and installation by a qualified contractor). We support our customers in Montreal , Laval , Longueuil , North Shore and South Shore in verifying conditions, preparing parts and submitting applications.
Quick comparison: wall-mounted heat pump vs. wall-mounted air conditioner
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A heat pump provides air conditioning and supplemental heating, for a lower energy bill and a better ROI over the year.
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A wall-mounted air conditioner only provides cooling; it remains relevant when existing electric heating is sufficient and the aim is for minimal entry cost.
The Sharp ZU1 series is ideal for customers who want a four-season system , filtered indoor air and controlled noise impact.
What makes the AirGreen difference
Proven installation method
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Technical survey of the site (structures, drilling, condensate drainage);
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Implementation plan with validated clearances ;
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Cold connections checked with a torque meter , leak tests, vacuuming and instrumented commissioning;
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Clean and durable finish: stainless steel fixings, protected wiring, careful sealing.
Full support
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Multi-room sizing and configuration advice;
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Financial aid eligibility verification;
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Annual HVAC maintenance contract to preserve performance and warranty;
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Rapid intervention throughout Greater Montreal : Montreal , Laval , Longueuil , North Shore , South Shore .
Tips for getting the most out of your Sharp ZU1
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Leave the machine in auto/inverter mode to finely modulate the power.
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Maintain stable instructions rather than large day/night differences.
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Keep 30–40 cm free in front of the exterior facade for airflow.
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Clean the inner head filters every 4 to 6 weeks during use.
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Schedule annual HVAC maintenance : electrical inspection, pressure/temperature readings, superheat/subcooling checks and exchanger cleaning.
Conclusion
This installation in Rosemont–La Petite-Patrie exemplifies what we strive to deliver: a clean, technical, and sustainable HVAC system that respects the architecture of Montreal plexes and maximizes comfort. The Sharp ZU1 wall-mounted heat pump provides the desired versatility—summer coolness, winter supplemental heat, cleaner air—while maintaining contained operating costs. At AirGreen, we apply the same high standards to every project, from the choice of capacity to the last screw, for a result that is efficient, quiet, and elegant.