Installation of a Zephyr R-32 wall-mounted heat pump in Plateau-Mont-Royal

Four-season comfort with a flat-roof HVAC system designed for the reality of Montreal plexes

Context of intervention

At AirGreen , we often encounter condominiums and plexes in the Plateau-Mont-Royal region where floor and backyard space is scarce. For this project, our client wanted a compact, efficient, and discreet system that cools in the summer and provides additional heat in the mid-season, while preserving the building's architecture. We recommend a new-generation Zephyr R-32 wall- mounted heat pump, with the outdoor unit installed on a flat roof to free up the facade and avoid encroachment into the alley. This solution is ideal for Montreal, Laval , Longueuil , the North Shore , and the South Shore .

The equipment chosen and its advantages for an urban plex

Why a Zephyr with R-32?

• High seasonal efficiencies : R-32 offers better performance than older refrigerants while reducing the total fluid charge.

• Inverter : fine modulation of power, long and stable cycles , concrete energy savings in air conditioning and additional heating.

• Silence : controlled acoustic profile, crucial for shared roofs and party walls.

• Compactness : size suitable for raising the roof and respecting clearances around the fan.

Capacity and areas served

After a simplified load calculation (surface area, glazing, orientation, infiltration), we selected a single-zone configuration between 9,000 and 12,000 BTU for the main living area. This range covers the majority of open-plan rooms in the Plateau apartments, with a margin for summer humidity peaks.

Flat Roof HVAC Installation Details

Support and anchoring: stability without compromising the membrane

The Zephyr condenser is raised on an aluminum frame placed on skids/soles resting on treated wooden crosspieces . This configuration:

• protects the elastomer membrane from punctures;

• promotes drainage and prevents the accumulation of water and blown snow ;

• limits the absorption of vibrations thanks to the anti-vibration pads under the plates.

The fasteners are tightened to the torque, with neoprene washers to preserve the structure. The fan orientation respects the recommended clearances (free front of at least 1 m and lateral ≥ 30–45 cm) to guarantee heat exchange and the longevity of the compressor.

Refrigeration path: cleanliness, performance and sustainability

• Rooftop routing in high-density insulated copper connections (UV protection), tied and raised to prevent any water stagnation.

• Waterproof passage at the parapet drop via a sheath and membrane-compatible mastic; air barrier restored on the interior side.

• Clean vertical descent in UV-resistant chute to the interior wall head (short back-to-back configuration to minimize pressure losses).

Condensate management and electricity

• Gravity drain from the indoor unit, controlled slope to the discharge point; no condensate pump required, guaranteeing silence and reliability.

• Power wiring on a dedicated circuit, rated circuit breaker and external proximity disconnect for safety and maintenance. Connections are labeled and tested.

Commissioning: rigorous method

• Nitrogen flushing in brazing, pressure test , then deep vacuum draw until stability (control of the rate of rise) to eliminate humidity and non-condensables.

• Weighing of the fluid according to actual lengths, opening of the valves, verification of the intensities and blowing temperatures .

• Remote control settings (modes, speed, swing , setpoint lock) and usage instructions.

Challenges of a Montreal flat roof… and our solutions

1) Wind and structural noise

Exposed roofs generate wind loads and noise transmission. Our raised frame, combined with anti-vibration pads and verified propeller alignment , prevents resonance within the structure. The fan is oriented so that the air discharge does not follow a parapet.

2) Defrosting and snow removal

The raised area ensures free flow during defrost cycles and prevents snow from accumulating on the coil. We maintain perimeter clearance for winter service and recommend manual de-icing if a persistent snowdrift forms after a storm.

3) Membrane integrity

No unnecessary through-fastening: loads are distributed via the cross members, and any technical penetrations are treated with compatible flashings and sealants. This approach protects the roof warranty and simplifies subsequent inspections.

Results obtained

Comfort felt

• Rapid drop in indoor temperature in air conditioning, even during urban heat waves.

• In mid-season, stable additional heating without overconsumption thanks to the inverter.

• Low noise level at low speed, suitable for teleworking and quiet nights.

Efficiency and savings

• Continuous modulation → less jolts , less wasted energy.

• Effective dehumidification : a moderate setting provides tangible freshness.

Good usage practices

Recommended settings

• In air conditioning, aim for 23–24°C with AUTO speed to let the inverter optimize the cycles.

• For additional heating, maintain a stable setting (avoid large day/night variations).

• Activate the swing to distribute the air in the open area.

HVAC Maintenance

• Indoor unit filters : rinse every 4 to 8 weeks during use.

• Roof: keep 1 m free in front of the battery, clear leaves and snow.

• Annual AirGreen visit : electrical inspection, pressure/temperature measurement, leak test, battery cleaning and parameter updates.

Security, Compliance and Documentation

Standards followed

• Tightening torques and flares comply with R-32 ; certified tools.

• Clear labeling of circuits, route diagram, before/after photo file .

• Dedicated outdoor disconnector and circuit breaker in accordance with local requirements.

Grants and programs

High-efficiency R-32 wall-mounted heat pumps may be eligible for assistance programs in Quebec (e.g., LogisVert or municipal initiatives, depending on the criteria). Our team supports:

• eligibility verification (performance, operating temperature, approvals);

• preparation of parts (detailed estimate, invoice, proof of installation);

• filing and tracking for Montreal, Laval , Longueuil , North Shore and South Shore .

What this rooftop configuration brings to the owner

Key Benefits

• Zero footprint in the yard or on the facade: aesthetics preserved, co-ownership satisfied.

• Performance maintained in winter thanks to the raising and clearing of the battery.

• Easy maintenance : clear technical access, disconnect switch within reach, legible route.

• Durability : UV-resistant materials, stainless steel/galvanized fixings, protection against stagnant water.

Pitfalls Avoided (and How We Avoid Them)

• Defrosting ineffective if the unit is too low → sufficient elevation.

• Membrane punching by concentrated feet → wooden sleepers + wide plates.

• Vibrations transmitted to structures → buffers and turbine/fan balancing.

• Counter-slope of the interior drain → laser verification and water test.

Typical steps of an AirGreen project on a flat roof

1. Technical visit : surveys, photos, access constraints, co-ownership rules.

2. Sizing and selection of BTU capacity .

3. Route plan (ducts, penetrations, position of the disconnector).

4. Installation : supports, connections, power supply, seals.

5. Commissioning : nitrogen, vacuum, loads, measurements, settings.

6. Submission of the end of work file and HVAC maintenance recommendations.

AirGreen, your HVAC partner on the Plateau and throughout Greater Montreal

We design and install heat pumps , wall-mounted air conditioners , central and multi-zone systems in Montreal, Laval, Longueuil, on the North Shore and the South Shore . Our promise: honest advice , clear quotes, clean execution and real after-sales follow-up . Whether it's a flat roof like this one or a backyard, we adapt our supports (wall, slab, roof), our chutes and our routes to combine performance and aesthetics .

Quick Questions

Is a flat roof always better?
When a yard is cramped or regulated, yes. However, we validate the loads , prevailing winds and the membrane before confirming.

Is a condensate pump necessary?
In this back-to-back configuration with controlled slope, no . We favor the gravity drain for reliability and silence.

How long does an installation of this type take?
Generally one day , depending on the accessibility of the roof and the length of the route.

Conclusion

This Zephyr R-32 wall-mounted heat pump installation on a flat roof in Plateau-Mont-Royal demonstrates our expertise: raised supports, clean refrigeration path , controlled sealing and rigorous commissioning. The customer benefits from lasting comfort , quiet operation and optimized consumption , with a system ready for assistance programs applicable throughout Greater Montreal .