Controlled comfort in a HoMa plex: a wall-mounted head installed to the millimeter for efficient airflow from the entrance
Project background
At AirGreen , we are working in a typical plex in Mercier–Hochelaga-Maisonneuve . The entrance room, bathed in light by a glass transom above the door, suffered from marked discomfort during heat waves and bitter cold. Our client wanted a compact, quiet HVAC solution capable of stabilizing the temperature of adjacent spaces without major renovations. We are proposing the installation of a Zephyr wall-mounted heat pump – a discreet format that fits perfectly into Montreal's urban housing.
Interior installation: installation close to the ceiling to optimize sweeping
The interior head is fixed a few centimeters from the ceiling , exactly above the transom. This positioning:
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promotes reverse stratification : the warm air blown in in winter spreads out under the ceiling then falls back down uniformly;
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allows efficient horizontal sweeping towards the corridor and the living room, the adjustable blade directing the flow under the lintel without hindering the opening of the door;
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frees up wall space: no furniture is impacted, and traffic remains fluid in the entrance.
The refrigeration passage is on the right side (classic Zephyr configuration), joining the external casing by a single perforation, which limits the refrigeration length to approximately 3 to 4 meters – the ideal layout for reducing pressure losses , maintaining efficiency and minimizing the noise level of the external compressor.
Condensate management: gravity as a priority
The installation level in relation to the window and the transom allowed us to maintain gravity drainage of the condensate in air conditioning mode. This choice:
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eliminates the need for a lift pump (less maintenance, no additional noise);
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reduces the risk of backflow during episodes of humid heat;
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simplifies annual HVAC maintenance (flushing of the pan and pipe).
Aesthetics and sealing: discreet capping and careful drilling
Externally, the refrigerant and power connections are protected by a discreet capping , adjusted to the color of the secondary facade overlooking the courtyard. The drilling passes through a single load-bearing wall; we apply a vapor barrier seal and UV-resistant exterior caulking , essential for durability and airtightness.
Why a wall-mounted heat pump in a HoMa plex?
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Compactness : no ducts or plenum required; the head is installed where it is most needed.
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Advantageous seasonal yield , especially with short line lengths and a direct route .
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Quiet : The Zephyr indoor unit maintains a low noise level at low speeds; the location above the door directs the diffusion away from the rest area.
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Flexibility of use : a responsive heating mode in the off-season and a precise air conditioning mode in summer, with a digital setpoint display that facilitates daily habits.
Salient installation details
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Working height : under ceiling, clearance optimized for the motorized shutter.
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Power supply : dedicated circuit with protection in accordance with the Quebec Electrical Code ; section and circuit breaker sized according to the outdoor unit nameplate.
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Communication and vacuum : torque tightening of flare nuts (controlled torque), triple vacuum draw to < 500 microns, verification by nitrogen leak test before releasing the fluid.
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Finish : rework of the moldings around the transom for a clean integration; flush interior hole cover.
Result: consistent comfort and simple control
At a set point of 23°C , air circulation covers the entrance, hallway, and adjoining living room. The sensation of draft is limited thanks to the fine adjustment of the fins . The customer notes increased thermal stability and a decrease in perceived humidity during hot periods.
Our recommendations for use and maintenance to maintain performance
Recommended settings
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Auto mode in the off-season ; manual switching between Heating (< 10°C ext.) and Cooling (peaks > 26–27°C).
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Instructions : 22–23°C for a comfort/consumption compromise.
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Sweeping : when cooling, direct slightly upwards to promote air mixing; when heating, horizontal then slightly lowering.
Annual HVAC maintenance
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Clean washable filters every 2–3 months of heavy use.
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Inspection of the condensate tray , flow test and anti-biofilm disinfection (important in urban environments).
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Checking the electrical tightening and vibrations of the outdoor condenser; dusting the coil and straightening the fins if necessary.
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Control of refrigeration load and subcooling/superheating using calibrated instruments – the only reliable way to ensure the promised seasonal efficiencies .
Best practices in the Montreal environment
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Clear the condenser in winter (snow, ice) and provide a raised support with snow guard if exposure requires it.
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Avoid temporary extension cords : supply dedicated circuit only.
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On the rear facade, choose a matching, UV-stable capping to preserve the aesthetics of the plexes ; when reselling, a clean installation reassures the buyer.
Key performance and eligibility points
High-performance wall-mounted heat pumps are generally eligible for energy efficiency assistance programs when certain performance and cold weather thresholds are met ( extreme cold models, recognized certifications). Eligibility varies depending on the exact model and the year of the program; we systematically check these criteria when submitting for our clients in Montreal, Laval, Longueuil, North Shore and South Shore .
What we bring to each installation
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Positioning study : we evaluate heights, air flows and obstacles (lintels, transoms, moldings) to aim for uniform comfort , without cold zones.
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Optimized refrigeration route : priority given to short lines , sealed holes and gravity drain to reduce risks and maintenance.
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Carpentry finish : respect for the moldings and architectural details of the HoMa , Rosemont and Le Sud-Ouest plexes.
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After-sales service : HVAC maintenance reminder and rapid availability during peak periods.
When to choose a multi-zone configuration?
If several distant rooms need to be covered (e.g. upstairs bedrooms and living room), we offer MultiZone systems compatible with wall-mounted or cassette heads. For a home with open spaces (entrance-living room-kitchen), a single well-positioned head – as here – is often sufficient, with controlled investment and consumption.
Frequently asked questions from our customers at HoMa
Doesn't placing it so close to the ceiling suffocate the device?
No. The required clearances are respected. This proximity improves air mixing and prevents direct blasts.
Is the noise noticeable in the entrance?
In steady state, the noise level remains low. The corridor acts as an acoustic buffer for the rest rooms.
What if the transom condenses in summer?
We adjust the shutter to limit direct cold air hitting the glass. Regular maintenance maintains effective dehumidification , which reduces condensation.
Conclusion: A well-placed mural changes everything
This Zephyr compact HVAC installation in Mercier–Hochelaga-Maisonneuve illustrates the importance of positioning , drain management and a short refrigeration path . The result: immediate comfort , silence and a neat finish – the winning trio for Montreal plexes.
Need a similar project in Montreal, Laval, Longueuil, North Shore or South Shore?
We evaluate your home, validate eligibility for current subsidies and provide a detailed quote . AirGreen supports each client, from design to HVAC maintenance .