An HVAC upgrade designed for Montreal winters: stability, silence and simplified maintenance access
Urban context and site constraints
In Rosemont–La Petite-Patrie, many flat-roofed plexes require a robust and membrane-friendly HVAC system . Here, we are installing a Sharp wall-mounted heat pump ( ZU1 series, R-32 refrigerant) with an outdoor condenser positioned on the flat roof . The immediate environment—parapet, roof vent, and snow cover—requires precise clearances to ensure performance, condensate drainage, and safe maintenance.
Why the Sharp ZU1 range for this project
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High seasonal efficiency thanks to inverter technology which modulates capacity according to actual demand.
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R-32 refrigerant, more efficient with reduced mass and environmentally beneficial.
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Designed to suit the cold climate of Greater Montreal , with an optimized defrost cycle and stable control electronics.
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Common capacity range (12k to 24k BTU) to accommodate sizing for typical plex apartments.
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Controlled noise level both indoors and outdoors, an essential criterion in densely populated areas.
Our approach: sizing based on the thermal loads of the housing, envelope measurements (windows, infiltration, orientation) and occupancy habits. This guarantees continuous operation at low speed, synonymous with comfort and energy savings .
Flat roof installation details
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Raised galvanized steel support resting on protective pads. The pads distribute the load and protect the membrane.
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Sufficient raising height to keep the unit above the snow and facilitate manual snow removal around the equipment.
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Clearances respected in relation to the parapet and obstacles (neighboring vent) in order to ensure undisturbed air intake/exhaust and maintenance access.
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Compact refrigeration path to the interior via sealed roof penetration (membrane compatible flashing and sealant). R-32 insulated copper pipes are neatly capped to the interior header.
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Vibration management via pads and stiffening of the frame to prevent any transmission to the light frame of the roof and limit structural noise in the housing.
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Winter condensate drainage : slope and free area under the unit so that water from defrosting drains properly, limiting ice formation.
Interior integration and air quality
The discreet, wall-mounted interior fan head ensures even distribution without drafts. The positioning takes into account furniture, shutter travel, and ceiling height to optimize stratification in heating mode.
We offer optional air quality optimization (improved filters, regular maintenance) to maintain machine performance and heat exchanger cleanliness.
Performance and comfort in practice
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Rapid temperature increases , then stable maintenance thanks to continuous modulation.
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Humidity better controlled in summer by operating at low speed which extends the air/exchanger contact time.
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Reduced noise : Elevated mounting, fan balancing and electronic control lower the perceived noise level on the roof and inside.
Electricity and protections
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Dedicated circuit compliant with Code, circuit breaker sized according to the nameplate, circuit breaker nearby on the roof side for safe work.
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Protected external wiring and clean routing to the panel. Connections are thermographically checked during commissioning to anticipate any abnormal heating.
Progress of the work
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Technical visit and load calculation: readings, validation of the location of the interior head and the passage of the connections.
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Roof preparation : tracing, membrane protection, leveling and support beam.
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Installation of the support and the outdoor unit, R-32 refrigeration connections, nitrogen tests and deep vacuum drawing .
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Electrical connections , power-up, mode settings and complete functional tests.
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Handover of the site : user demonstration and seasonal maintenance instructions.
In a comparable urban context, this type of intervention is generally carried out during the day , without disrupting neighborhood life.
Recommended HVAC maintenance
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Clear snow around the condenser after heavy snowfall; never obstruct the grilles.
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Clean the inner head filters every 4 to 8 weeks during the usage season.
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Annual inspection by our technicians: checking pressures, modulation, sealing, condensate flow, tightening the terminal block and cleaning the exchanger.
Regular maintenance maintains performance, extends lifespan and prevents increases in consumption.
Points of attention and mistakes to avoid
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Direct support on unprotected membrane: risk of punching. Always use suitable pads.
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Insufficient height above the snow: accumulation and icing possible.
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Tortuous line paths : pressure losses, trapped oil, reduced efficiency.
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Failure to comply with clearances : air recirculation and defrost cycles too frequently.
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Lack of circuit breaker nearby: non-compliance and risk during interventions.
Grants and support
Depending on the capacity and efficiency ratings, a recent R-32 wall-mounted heat pump is often eligible for assistance programs in Quebec. We guide our clients for files covering Montreal , Laval , Longueuil , the North Shore and the South Shore : eligibility verification, technical documents, proof of installation and compliant invoicing.
Result for the customer
This installation provides four-season comfort , an optimized energy bill and easy maintenance access to the roof thanks to the raised support. The careful finish (short path, continuous insulation, standardized clearances) ensures long-lasting reliability, even during Montreal's extreme cold.