A roof installation designed to last: raised structure, UV insulation of the connections and simplified maintenance, for 4-season comfort in a residential building in the Southwest .
An HVAC modernization that respects the roof and the neighborhood
In this typical residential building in Southwest Montreal (flat roof, parapets, shared technical access), we are installing a GREE FreeMatch R32 MultiZone heat pump to supply several interior zones. The objective is threefold: reduce the energy bill , decouple room-by-room temperatures and minimize the acoustic impact on the immediate neighborhood and the interior courtyard.
Why choose a MultiZone R-32 system
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Flexible layout : a single outdoor unit serves multiple wall heads/consoles ; ideal for 3.5, 4.5 and adjoining apartments.
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High seasonal efficiencies (SEER/HSPF) and reliable heating in cold weather thanks to the optimized defrost algorithms of GREE R-32 platforms.
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R-32 refrigerant : better heat transfer coefficient and lower GWP than R-410A, an advantage for the environment and efficiency.
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Acoustic comfort : inverter compressor and exterior fan management for quiet nights — important in dense neighborhoods like Montreal , Laval or Longueuil .
Technical configuration delivered by AirGreen
Raised and decoupled outdoor unit
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Raised aluminium base with anti-vibration feet : secure roof clearance (winter snow removal, runoff) and reduced noise transmission .
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Clean routing of refrigeration lines : grouped bundles, closed UV-resistant insulation, spaced collars to avoid pinch points and facilitate maintenance.
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Flared connections to the couple (with nitrogen purge) and pressurization with nitrogen before deep vacuum drawing ; digital vacuum gauge to validate the seal.
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Outdoor electrical sectioning within service range, wiring in waterproof sheath with expansion loops.
Roof drilling and waterproofing
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Drilling into a dedicated passage box , with insulated sleeve and vapor barrier .
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The joints are made with mastics compatible with bituminous/elastomer membranes, then protective flashings to preserve the roof warranty.
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Slope of the connections ensured to avoid oil pockets and preserve the return of oil to the compressor.
Internal distribution
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3 to 5 zones depending on the apartment, with wall heads positioned high on the exterior walls.
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Gravity drainage preferred for each evaporator when the architecture allows it; condensate pump only if necessary, mounted on silent blocks and with overflow detector .
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Fine-tuning of remote controls: ventilation curves, eco settings, child locks, night modes.
Key steps in our HVAC installation
1. Load study and balancing scenarios
We model the thermal envelope: facade orientation, glazing, roof insulation, thermal bridges. Zone-based BTU sizing prevents underheating in extreme cold and short cycles in summer.
We simulate actual usage (occupancies, open doors, kitchens) in order to choose the capacities per head and the equivalent length of each circuit (pressure losses, differences in level, bends).
2. Site preparation and roof protection
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Protective mats and distribution boards to prevent puncture of the coating.
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Tracing of technical trenches, clear identification of beams (color codes) to facilitate future maintenance.
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Coordination with the condominium association for power cuts and roof access.
3. Brazing, vacuum and commissioning
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Silver brazing (if extension required) under continuous nitrogen.
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Pressurization to the values prescribed by GREE; prolonged maintenance to detect any drift.
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Vacuum ≤ 500 microns , stability controlled; fluid release, then superheat/subcooling and operating current readings .
4. Acoustic and anti-vibration optimization
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Adjustment of exterior ventilation speeds and nighttime silence mode .
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Elastomer pad and spacers to filter low frequencies; air discharge orientation to avoid recirculation against parapet walls.
5. Final checks and occupant training
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Test of each zone in heating and air conditioning with validation of ΔT .
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Verification of defrosting under simulated conditions, testing of condensate pumps (if present).
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Training: stable instructions, eco programming, filter maintenance, good door/window practices.
Results: controlled comfort and reduced consumption
The customer benefits from increased thermal stability , better humidity control in summer, and a significant reduction in bills thanks to inverter modulation. Noise pollution is contained, both for occupants and neighbors. The HVAC maintenance reminder is included in our annual monitoring.
Salient details visible on the pose
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Raised structure : the outdoor unit is clear of the roof plane, which facilitates snow removal and limits corrosion.
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Grouped refrigeration bundles : continuous insulation, sheathed junctions, spaced collars — a clean assembly that simplifies diagnostics .
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Radius of curvature respected and clearance around the fan; no immediate obstacle (chimney, low wall) likely to create air recycling.
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Maintenance access : valve, fittings and electrical panel accessible without dismantling the structure.
Grants and eligibility (Greater Montreal)
High-efficiency R-32 MultiZone heat pumps may be eligible for current assistance programs (depending on SEER2/HSPF2, low-temperature operating ranges, and unit configuration). Our AirGreen team handles:
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of eligibility verification ,
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preparation of documents ,
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and optimization of settings to maximize savings in Montreal , Laval , Longueuil , North Shore and South Shore .
HVAC maintenance recommended for longevity
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Filters : monthly cleaning during periods of intensive use; periodic replacement if specific media.
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Batteries (evaporators and condenser): annual gentle wash; fin inspection/degreasing if unit near a kitchen outlet.
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Checking of external insulation (UV/friction), re-installation of collars after a freeze/thaw cycle.
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Winter : Keep snow clearance around the outdoor unit; check the defrost drain.
An AirGreen HVAC maintenance contract ensures long-term performance and secures the manufacturer's warranty.
Pitfalls to avoid on Montreal roofs
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Direct supports without load distribution: risk of punching and sealing disputes.
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Air recirculation caused by a wall/parapet that is too close: loss of capacity during heat waves.
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Unprotected UV bundles : insulation cracks, condensation and losses.
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Condensate pumps not required: use gravity instead; if a pump is required, provide a detector and easy access .
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Excessive equivalent lengths and unnecessary “serpentine” loops: pressure losses, trapped oil.
Tips for optimizing comfort and bills
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Stable settings : let the inverter modulate; avoid repeated variations of ±3°C.
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Seasonal modes : In the off-season, favor Dry to control humidity without overcooling.
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Night : Quiet mode and sweep limitation for draft-free sleep.
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Doors : open if you want to share the air conditioning between adjoining rooms; closed to prioritize one area.
Why AirGreen for your MultiZone projects?
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Local expertise in apartment buildings and condominiums in Greater Montreal.
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Mastery of the new R-32/R-454B ranges : GREE , Fujitsu , Midea , Sharp , etc.
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Measurable quality : vacuum reports, tightening torques, end-of-site photos, harness diagrams provided to the customer.
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Complete service : study, HVAC installation , HVAC maintenance , grant support — in Montreal , Laval , Longueuil , North Shore and South Shore .
Express FAQ
Is a MultiZone suitable for a 6-unit apartment?
Yes, depending on the configuration: we often prefer 1 condenser per dwelling for autonomy, but shared solutions are possible depending on the electricity available and the co-ownership rules.
What happens if a head fails?
Other areas remain operational; we are stocking common parts to reduce lead times .
Can we add a head later?
On some FreeMatch R32 bases, yes if the remaining capacity and authorized lengths allow it. We check before any extension.
Balance sheet
The GREE FreeMatch R32 installed on roofs in the Southwest offers a rare combination: zonal flexibility , efficiency in cold climates and respect for the roof thanks to a raised, clean and durable installation. The result: comfortable homes all year round and a sustainable investment for co-owners.