A heating and air conditioning solution designed for an urban building
In a residential building in the Southwest district of Montreal , we are installing a Zephyr wall-mounted heat pump with a condenser positioned on the flat roof . The goal of the condominium association is twofold: to improve the comfort of the top-floor units in both summer and winter, and to preserve the aesthetics of the street-side facades. The rooftop configuration perfectly meets these expectations while respecting the access and maintenance constraints specific to urban buildings.
Why the Zephyr heat pump is suitable for this project
We favor a compact, efficient, and quiet heat pump capable of providing reliable heating in extreme cold and consistent air conditioning during heat waves. The Zephyr range meets these criteria with:
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Inverter compressor ensuring fine modulation of power and significant electricity savings throughout the year.
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High-efficiency exchanger promoting rapid temperature rise and remarkable stability in heating mode.
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Low noise level , beneficial for both occupants and the neighborhood, particularly on shared roofs.
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Anti-corrosion treatments for fins, useful in urban environments subject to freeze/thaw cycles and acid rain.
Inside, wall-mounted headers serve the main rooms. Outside, the condenser is insulated from gravel projections and raised for optimal clearance, a prerequisite for the longevity of the unit.
Engineering Choices for a Successful Flat Roof Installation
Support, clearances and load management
The condenser is placed on a raised aluminum support fixed to anti-vibration pads . This structure distributes the loads on the gravel and protects the membrane. We keep:
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Sufficient peripheral clearance for air intake and discharge, avoiding any recycling of hot air.
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A ground clearance (raise) that keeps the unit above snow accumulation and meltwater.
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A service corridor allowing safe access to the panel and service valve for maintenance.
This approach reduces vibration transmission to the structure and simplifies annual inspections.
Roof crossing and connection route
The refrigerant connections and the communication/power cable run in a sealed, securely fastened and sealed metal technical box . The pipes are UV-insulated and protected against abrasion. We limit the circuit length to optimize efficiency and minimize pressure losses.
Inside, the lines are neatly covered up to the wall units. The condensate drain is treated differently depending on the season:
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In air conditioning mode , gravity evacuation to a planned drainage point, avoiding any backflow.
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In heating mode , management of defrost water on the roof with sufficient slope to prevent ice from forming under the appliance.
Power supply and compliance
We install a code-compliant, waterproof disconnect switch in close proximity to the unit. The dedicated 240V circuit is protected at the home's electrical panel. Grounding and polarity are verified at every step. Clear labeling simplifies future repairs.
Commissioning and essential checks
Commissioning follows a strict protocol:
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Nitrogen test and leak test of connections.
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Deep vacuum (≤ 500 microns) and stabilization.
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Weighing/adjusting the refrigerant according to the actual pipe length.
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Functional checks in cooling and heating: intensity, overheating/subcooling, blown temperatures, and communication between cards.
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Calibration of shutters and air flow adjustments according to the rooms served.
Building context and constraints resolved
Dense urban environment
The building, bordered by neighboring walkways and rooftops, requires minimizing visual impact and noise. The rooftop positioning keeps the condenser away from neighbors' windows and preserves the area's brick facades. We maintain safety margins with respect to railings and metal edges, and we pay attention to the direction of the airflow so as not to disturb common areas.
Access and security
Access to the roof is via a hatch; we plan the intervention during a dry weather window , with lifelines if necessary. Handling (lifting of the unit, support and tools) is organized to avoid any aggressive contact with the membrane and limit back and forth movements.
Membrane protection
In addition to anti-vibration pads, we use distribution pads under the support brackets. All holes are sealed and sealed according to industry standards. We submit a photo report to the union to ensure traceability of the work.
Results obtained and benefits for occupants
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Immediate comfort : uniform temperature in the rooms concerned, precise control thanks to Inverter modulation.
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Reduced noise : discreet noise level on the roof and inside; no perceptible hum in the bedrooms.
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Energy efficiency : continuous operation at low speed preferred, guaranteeing savings over the year.
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Easy maintenance : clear access to the condenser and connections; washable interior filters and simplified HVAC maintenance routine.
Best practices specific to flat roof installations
Defrosting and water management
In winter, the defrost cycle generates water. We plan:
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A clearance under the unit for free drainage.
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The orientation of the frame so that the water naturally follows the slope of the roof, away from traffic areas.
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Sufficient elevation to prevent snow from forming on the fan.
Preventive maintenance
We recommend annual HVAC maintenance : cleaning the outdoor coil, checking tightness of connections, checking refrigeration parameters, and updating seals if necessary. For indoor units: washing filters, inspecting condensate trays, and light disinfection to maintain healthy air quality .
Montreal winter: some precautions
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Do not pile snow against the device when clearing snow.
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Keep a free radius of 60–90 cm around the condenser.
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Avoid installing the unit under direct ice discharge; a deflector may be added if ledges form.
Grants and Eligibility
High-efficiency heat pumps may be eligible for assistance programs in Quebec. Depending on the exact configuration and certified performance of the installed Zephyr model, it may be possible to benefit from contributions (e.g., municipal and provincial programs and partner offers). We systematically verify the AHRI and eligibility criteria before submitting applications. Our team assists co-owners in compiling evidence (invoices, photos, certificate numbers).
What more we bring to Montreal, Laval, Longueuil, North Shore and South Shore
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Accurate sizing : We evaluate the envelope, orientation and living habits to choose the right BTU capacity and number of heads.
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Impeccable finishes : aligned covers, clean holes, tidy wiring, calibrated support.
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Respect for deadlines : coordination with the union and the roofing contractor as needed.
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After-sales service : maintenance reminders, rapid availability in the event of an alert and a team trained in advanced diagnostics.
Advice for co-ownerships considering rooftop installation
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Validate the building regulations : authorized location, permissible load, maximum noise.
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Provide a secure access hatch : this determines future maintenance.
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Standardize the support : same height and same orientation for all units to standardize the aesthetics and facilitate snow removal.
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Install a visible and labeled disconnect for each condenser.
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Schedule an annual maintenance in early summer to cover air conditioning needs and a quick winter check before December.
Summary testimony of the occupants
The co-owners appreciate the temperature stability , the noise reduction and the reduction in their bills compared to old window air conditioners. The aesthetics of the facades are preserved; access to the roof remains free thanks to the service corridor left around the condenser.
Want a similar project?
Whether your building is located in Montreal , Laval , Longueuil , on the North Shore or the South Shore , we design and build sustainable HVAC systems , adapted to local architecture and the Quebec climate. Our team guides you from the choice of heat pump to commissioning, with particular attention paid to the roof and waterproofing.