An intervention designed for four-season comfort and durability
At AirGreen , we approach each HVAC installation as a coherent whole: equipment selection, building location, installation details and commissioning protocols. In this project in Villeray–Saint-Michel–Parc-Extension , we are installing two Midea28 (R-454B) wall-mounted heat pumps to serve two separate areas of a flat-roofed plex. The client's goal: to ensure quiet air conditioning in the summer, efficient heating in the winter, and controlled operating costs all year round.
Client context and needs
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Residential complex in an urban area, gravel roof with new membranes.
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Neighborhood and accessibility constraints: minimize vibration transmission and facilitate seasonal maintenance.
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Priorities: low temperature performance , defrost reliability, safe access for technicians, membrane protection and grant eligibility .
What we have achieved
1) Choice of range: Midea28 to R-454B
The Midea28 is a new generation wall-mounted heat pump that runs on R-454B (A2L) , a refrigerant with a lower GWP than R-410A. It offers capacities of 9,000 to 33,000 BTU and performs very well in cold climates thanks to its inverter compressor and optimized control electronics.
Benefits for a Montreal plex:
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Reliable heating down to very cold (operating ranges suitable for -30°C depending on capacity).
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High SEER/HSPF , particularly beneficial in mid-season.
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Fine modulation that stabilizes temperature and limits ON/OFF cycles.
2) Exterior installation: stability, silence and protection of the roof
We place the two condensers on aluminum structures fixed on 4x4 beams and protective soles . Blue anti-vibration pads are placed at each foot to mechanically isolate the units from the load-bearing slab and the frame.
Key points of the installation:
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Load distribution to preserve the membrane; no hard points.
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Peripheral clearances respected to avoid air recycling and ensure effective defrosting.
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Orientation of the blowers opposite to obstacles (low walls, roof outlets) in order to stabilize the air flow in winter.
Result: a silent installation, stable in the wind and fully serviceable without disturbing the neighborhood.
3) Refrigeration path and power supply
The insulated refrigeration lines are grouped and guided by clamps with controlled bend radii. We maintain a compact total length (≈ 6–9 m per unit) to minimize pressure losses and remain within the specifications of the Midea28. Communication wiring and dedicated power supply are routed under protection, with an external circuit breaker accessible for each machine.
AirGreen Procedures:
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Brazing under nitrogen , leak testing with dry nitrogen .
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Deep vacuum draw until stabilization (triple point if necessary).
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Subcooling/superheating checks according to the conditions of the day, then recording of the measurements in the commissioning sheet.
4) Condensate management and interior integration
Each zone receives a wall-mounted head positioned to sweep the living room without direct air flow onto the sleeping areas. The condensate drain is preferred by gravity ; a mini-pump is considered only when the configuration requires it. The inverter modulation allows discreet operation in the evening , ideal for bedrooms located on the upper floor of the plex.
5) Salient installation details
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Flat gravel roof : aluminum structures on 4x4 and soles to protect the membrane and avoid any punching.
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Anti-vibration pads under each foot: greatly reduced structural noise for the home and the neighborhood.
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A2L / R-454B : Compliant electrical and signal routing, clear identification of refrigerants with safety labeling.
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Installation levels made (spirit level visible during construction) to ensure correct drainage of defrosting water.
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Compact and protected refrigeration path ; connections neatly grouped at the back of the units.
Deadlines, coordination and security
Organization of the site
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Technical survey : 45–60 minutes to check passages, clearances and electrical panel.
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Installation : generally one day for two single units, including testing.
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Customer training : programming, filters, heating/air conditioning switch, HVAC maintenance advice.
Security and Compliance
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Compliance with fire clearances for exhausts and ventilation caps.
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Circuit breaker near each condenser, labeling and wiring diagram recorded.
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Membrane compatible flashings and sealants for any penetration.
Maintenance: ensuring long-term performance
User Interview
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Filters : Rinse every 4–8 weeks during periods of heavy use.
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Clearances : Keep 50–60 cm around condensers; remove leaves and debris.
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Heating mode : do not obstruct the defrost water drain in winter.
AirGreen Maintenance
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Annual inspection : electrical tightening, exchanger cleaning, refrigeration parameter check, fan test, check of silent blocks and flow.
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Seasonal optimization : mid-season usage tips to maximize savings.
Grants and Eligibility
New generation wall-mounted heat pumps (R-454B/R-32) , with cold climate performance and recognized certifications, are generally eligible for current grant programs (depending on capacity and Energy Star criteria). We support our customers in Montreal , Laval , Longueuil , North Shore and South Shore in verifying eligibility , collecting proof of installation and submitting files.
Measurable results after commissioning
Comfort and silence
The Midea28's inverter modulation stabilizes the temperature and maintains low noise levels in sleeping areas. Defrost cycles are short and smooth, with no noticeable drop in comfort.
Energy savings
By replacing electric baseboard heaters and older air conditioners, the heat pump reduces annual energy consumption. The savings are particularly noticeable in mid-season thanks to its low-speed operation and high SEER rating.
Sustainability of the installation
The combination of aluminum structures + soles + anti-vibration pads protects the roof, reduces mechanical wear and facilitates maintenance, extending the life of the devices.
Why entrust your project to AirGreen?
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Mastery of Montreal flat roofs : loads, sealants, blower orientation and frost management.
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Strict refrigeration procedure : deep vacuum , documented tests, recorded values.
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Complete support : sizing, selection of recent brands for R-454B/R-32 (Midea, Gree, Fujitsu, Sharp), subsidies , scheduled maintenance and responsive after-sales service.
Are you planning an installation in Montreal, Laval, Longueuil, on the North Shore or the South Shore? We size, install and maintain wall-mounted heat pumps adapted to your building, with particular attention to silence , durability and energy savings .
Useful keywords: wall-mounted heat pump , Midea28 , HVAC installation , HVAC maintenance , Montreal , Laval , Longueuil , North Shore , South Shore , R-454B , Inverter , flat roof .