An interior head placed to the millimeter in a narrow corridor: precise comfort, silence and controlled aesthetics in a Villeray plex
Housing context and objectives
At AirGreen , we are working in a typical Villeray–Saint-Michel–Parc-Extension plex , on the upper floor of a modernized 1950s building. The owner wanted stable heating in winter and gentle air conditioning in summer, while preserving the passage in a narrow corridor leading to the bedrooms. We are installing a Sharp wall-mounted heat pump from the ZU1 range (R-32) whose interior head is integrated in the upper part, just above a lintel, to efficiently serve the sleeping area without obstructing the opening of the doors or the recessed lighting in the ceiling.
Why the Sharp ZU1 (R-32) range in a Montreal plex
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High seasonal efficiency thanks to the inverter compressor and R-32 refrigerant, beneficial for performance and environmental footprint.
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Extreme cold weather range adapted to the climate of Greater Montreal: capacity for when the mercury drops, ideal for Montreal , Laval , Longueuil , North Shore and South Shore .
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Very low acoustics , both inside and outside, limiting noise pollution in corridors and shared courtyards.
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Precise air distribution : motorized flap and fine control electronics to send treated air to adjacent rooms without direct air current in the passage.
Reading the site: constraints of a narrow corridor
The hallway features a low ceiling with molding and a solid wood door frame in the immediate vicinity. The usable installation space is limited in height and width. Our challenges:
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Ensure upper clearances for air suction despite the molding,
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Ensure a door opening radius without hitting the head cover,
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Maintain a clear passage and avoid any risk of snagging,
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Maintain gravity drainage of condensates , even with a high-positioned hole.
Choice of location and preparation
We are choosing a high central installation , a few centimeters below the ceiling to optimize the return of hot air in winter and take advantage of the air mixture in the corridor. The wall support is laser aligned to guarantee horizontality despite the slight irregularities of the old plasterboard.
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Mounting plate anchored to studs, with dowels suitable for off-stud areas, to avoid any resonance.
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Discreet through-hole immediately behind the unit; sloped outwards for natural condensate drainage.
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Sheath and elastomeric sealant for airtightness, limiting thermal bridges and parasitic odors.
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Covered routing (discreet capping on the outside) to protect the refrigerant connections and the communication cable to the condenser.
Installation details: our step-by-step
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Measurement survey : checking ceiling heights, wall thickness and clearance around the molding.
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Electrical check : dedicated circuit, compliant rating and circuit breaker, external disconnect switch on the condenser side for maintenance safety.
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Installation of the plate : digital control, stainless steel screws and support washers for uniform pressure on the plasterboard.
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Drilling Ø65–75 mm with outward slope ; internal chamfer to avoid damaging the line insulation.
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Pre-fabrication of connections : soft bends, continuous insulation, butyl tape at the junctions. Estimated total length ≈ 3–4 m between the head and the condenser, sufficient for a direct route without unnecessary bends.
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Refrigeration connections : tightening to the prescribed torque , deep vacuum (micron control) and vacuum holding before releasing the fluid.
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Condensate management : gravity via the same sheath, continuous slope; no pump required, therefore silence and improved reliability.
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Commissioning : heating and cooling tests, control of blowing temperatures, verification of the shutter, measurement of intensity and acoustics under partial load.
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Finishing touches : covers closed properly, screw covers, local repainting around the hole if necessary.
Air settings for a corridor
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Orient the shutter slightly towards the furthest room to draw the tempered air by the Venturi effect into the corridor.
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Auto Preferred Speed : Fan modulation reduces noise in a reverberant space.
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Heating mode : gentle and continuous setting, avoiding short cycles which accentuate temperature differences in a narrow area.
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Dehumidification mode in summer: useful during humid periods, without excessively cooling the passage.
Results obtained
The corridor becomes a diffusion plenum : the air is distributed naturally towards the bedrooms and the adjoining living room. Noise levels remain low, even at night. In winter, the temperature rises regularly and consumption remains low thanks to inverter modulation. In summer, the corridor remains dry and cool, which improves the comfort of the adjacent rooms.
Best practices for HVAC installation in hallways
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Respect the upper clearances for air suction; in the presence of molding, aim for a minimum of 3–5 cm.
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Avoid air returns obstructed by a light fixture or soffit.
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Prioritize gravity for condensate ; a pump is only considered as a last resort.
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Limit bends on refrigeration lines and protect each passage with a sheath.
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Check that the doors open at 90–110° to prevent contact with the front of the unit.
Recommended HVAC maintenance
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Filters : clean every 4 to 8 weeks depending on use and the presence of animals.
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Exchanger : light dusting with a vacuum cleaner fitted with a brush, without deforming the fins.
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Outdoor condenser : gentle rinsing in spring, clearing snow and leaves in season.
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Annual AirGreen inspection : electrical tightening, verification of refrigeration parameters, calibration of the shutter and inspection of the seals.
Capacity selection and sizing
Even in a confined space, we size the heat pump based on the priority heating load . In a Villeray apartment complex, a 12,000 to 18,000 BTU unit is common to serve a hallway and two adjacent rooms, subject to actual heat losses (orientation, insulation, infiltration). This approach guarantees comfortable modulation and year-round energy savings .
Aesthetics and integration
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The Sharp white shell aligns with the ceiling molding for a continuous visual reading.
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The filler paste around the sheath is smoothed before painting to make the work invisible.
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On the exterior, the capping follows the lines of the facade, a neutral color to blend in with the cladding.
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The vibrations are decoupled by the plate and the screws, avoiding any resonance in the plasterboard of the corridor.
Grants and support
Efficient R-32 heat pumps such as the Sharp ZU1 series are generally eligible for assistance programs in Quebec. We assist our customers with:
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eligibility verification according to performance reports,
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collecting serial numbers and proof of installation,
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submission of files on time.
This service covers all of Greater Montreal: Montreal , Laval , Longueuil , North Shore and South Shore .
Common mistakes to avoid in this type of installation
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Sticking the head to the ceiling : the suction is muffled, the noise increases and the efficiency decreases. Always keep some clearance at the top.
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Horizontal condensate without slope: source of odors and leaks. Gravity is the rule.
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Undersizing the capacity for a multi-room hallway: this causes short cycles and recurring discomfort.
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Forget to open the doors when positioning: the hood can become an impact point.
Why entrust your HVAC installation to AirGreen?
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Experience of Montreal plexes : narrow corridors, moldings, old partitions, complex openings.
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Multi-brand expertise (Sharp, Gree, Fujitsu, Midea, etc.) to recommend the right equipment.
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Quality procedure : deep vacuum checked, tightening torques checked, load tests, photo report and initial setting.
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After-sales service : maintenance reminders, priority availability during cold weather, common parts in stock.
Site sheet – key points
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Machine : Sharp ZU1 range , wall-mounted heat pump ( R-32 ), capacity adjusted to the housing.
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Room : narrow corridor with molding, Villeray–Saint-Michel–Parc-Extension .
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Installation : plate on uprights, drilling at a slope , gravity drainage of condensates.
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Route : insulated and covered connections to the condenser, length approx. 3–4 m .
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Objective : four-season comfort, silence , diffusion of air to the rooms without obstructing the passage.
Do you want the same level of integration in a hallway or a high-traffic room in Montreal , Laval , Longueuil , on the North Shore or the South Shore ? Our team studies, sizes and installs your heat pump with exemplary finishes and complete support for subsidies.