Installation of a FUJITSU AIRSTAGE ORION XLTH+ wall-mounted heat pump (AOUH15KTAP1) in the Saint-Édouard neighborhood, Rosemont–La Petite-Patrie, Montreal

Two outdoor units, a laneway wall, and plenty of calculations before drilling the first hole

The project was located in Saint-Édouard, in that part of Rosemont–La Petite-Patrie where duplexes and triplexes nearly touch, the laneway serves as the backyard, and every metre of exterior wall is a scarce resource. The owner called us in June, after two summers of hauling a portable air conditioner from room to room and an entire winter of watching his electricity bill rise because of the second-floor electric baseboards.

The request was simple: provide serious cooling in the summer and reduce some of the electric heating in the winter. The constraint was much less so. The ground-floor unit had just been equipped with a wall-mounted heat pump FUJITSU AIRSTAGE, and its outdoor unit already occupied the best section of the side wall. All that remained was a strip of gravel about one metre wide, wedged between the parged foundation and the neighbour’s fence.

This is exactly the kind of Montreal configuration the ORION XLTH+ series was designed for.

The starting point: a baseboard-heated duplex with no ductwork

The second floor totaled approximately 850 square feet: an open southwest-facing living-dining room, two bedrooms, and an enclosed kitchen. There was no ductwork and no reasonable way to install any without demolishing the original ceilings.

Our load calculation produced the following figures:

• Estimated cooling load: approximately 13,200 BTU/h for the main area, with significant solar gain in the late afternoon through three southwest-facing windows.
• Estimated heating load: approximately 17,000 BTU/h at Montreal’s design temperature (-23 °C), for the portion served by the unit.
• Client objective: cover as many heating hours as possible with the heat pump, while keeping the existing baseboards as supplemental heat in the bedrooms.

These figures led us to choose the 15KTAP1 model (indoor unit ASUH15KTAS, outdoor unit AOUH15KTAP1) rather than the 12KTAP1. The 15K’s heating capacity — up to 28,000 BTU/h at peak — made it possible to get through cold spells without running the baseboards continuously.

Why the ORION XLTH+ and not another wall-mounted unit

We install several brands every week in Montreal, Laval, and Longueuil. The choice is never based on habit, but on how well the building’s actual needs match the unit’s measured performance.

The number that determines everything: capacity maintained at -30 °C

Most wall-mounted heat pumps advertise a heating operating range down to -25 °C or -30 °C. The real question is not whether the unit starts at that temperature, but how much heat it still produces.

For the ORION XLTH+, the published figures are as follows, expressed as a percentage of rated capacity:

In other words, at -30 °C, the 15KTAP1 still provides its full rated capacity. There is no low-temperature shutoff device programmed into the unit: it continues heating as long as the operating range (-30 °C to 24 °C) is respected. For a Rosemont duplex where the goal was to reduce baseboard use, this feature was worth more than any sales pitch.

Efficiency ratings, translated into homeowner terms

The 15KTAP1 delivers a TRÈS2 (SEER2) of 28.7, a CPSC2 Region V (HSPF2) of 10.7, a TRE2 (EER2) of 15.4, and a coefficient of performance of 4.72. The last figure is the most telling: under test conditions, the unit delivers nearly 4.7 times more thermal energy than it consumes in electricity. An electric baseboard heater, by contrast, tops out at 1.

The unit is ENERGY STAR certified, including the Cold Climate and Most Efficient designations—a point that directly affects eligibility for rebate programs, which we discuss later.

R-32 refrigerant and the environmental question

The ORION XLTH+ runs on R-32, which has a global warming potential of 675, compared with 2,088 for R-410A: a 68% reduction. These units also require a lower refrigerant charge for equivalent capacity. The A2L classification, however, involves specific handling procedures, suitable detectors, and dedicated tools. This is another reason to entrust the installation to a trained team holding a valid RBQ licence.

The installation process, hour by hour

The team arrived at 7:30 a.m. The project was completed and commissioned at 3:10 p.m. the same day.

1. Outdoor unit positioning. The gravel strip did not allow for a ground-level pad without encroaching on the walkway. We opted for galvanized steel wall brackets, anchored into the stuccoed foundation with mechanical anchors sized for the unit's weight (44 kg empty, and more when charged). The bottom of the chassis is approximately 450 mm above the gravel—high enough to ensure that accumulated snow and defrost ice never block the lower air intake.
2. Coordination with the adjacent unit. The two units share the same wall. We maintained sufficient side clearance between the two chassis and observed the manufacturer's required rear clearance so that neither unit would draw in air discharged by the other. Air recirculation between two poorly spaced units causes heating performance to drop long before a customer notices it on their bill.
3. Drilling and conduit routing. Since the shared wall is brick over concrete block, the opening was core-drilled with a slope toward the outside for the condensate drain. The drainage line is visible in the photo: it runs directly into the gravel bed, which serves here as a natural percolation area. On a concrete slab, we would have routed the condensate to the alley drain.
4. Refrigerant line routing. Actual run length: approximately 7 metres, versus a maximum permitted length of 20 metres and a factory charge covering 14.9 metres. No refrigerant had to be added. The line sizes are 3/8 in. for gas and 1/4 in. for liquid, separately insulated along their entire length, including the outdoor section protected by a sleeve.
5. Flares and leak testing. Each flare was made using an eccentric flaring tool and tightened with a torque wrench to the manufacturer's specifications. A dry nitrogen pressure test was held, followed by evacuation to below 500 microns with a ten-minute standing vacuum test. This is the step most often rushed in the industry, and it is the one that determines the compressor's service life.
6. Electrical connection. Dedicated 208–230 V / 60 Hz / single-phase circuit with a 20 A circuit breaker and an outdoor disconnect switch within sight of the unit. The base pan heater, essential for preventing ice buildup beneath the heat exchanger during winter defrost cycles, was commissioned at startup.
7. Commissioning and configuration. Pressure and duct temperature checks, delta T measurement at the air handler, then pairing the built-in Wi-Fi with the AIRSTAGE app on the homeowner’s phone. We also enabled the outdoor low-noise operating mode, a setting we systematically recommend in densely populated areas.

The question of noise in a Rosemont alley

The outdoor unit of the 15KTAP1 is rated at 51 dB(A) in cooling and 49 dB(A) in heating. Indoors, the wall-mounted unit goes down to 26 dB(A) in quiet mode on this model, with six fan speeds plus automatic mode.

In an area like Saint-Édouard, where a neighbour’s bedroom window may be four metres from the unit, these figures are not merely decorative. Montreal boroughs regulate the sound level of mechanical equipment measured at the property line, and requirements vary from one borough to another. We check the applicable regulations before every installation, and our office team can also answer these questions by phone for areas in Montreal, Laval, Longueuil, the North Shore, and the South Shore.

The mistakes we see most often, and what they really cost

Every year, we take over dozens of installations completed by others. Four situations come up constantly.

Oversizing “to be sure”

An oversized unit reaches its setpoint too quickly, stops, restarts, and no longer dehumidifies properly in summer. The result is a cold, humid home with a persistent feeling of discomfort. The 15KTAP1 modulates from 3,900 to 19,400 BTU/h in cooling: this modulation range, not the maximum capacity, is what ensures true comfort.

Installing the outdoor unit on the ground in a snowy area

An outdoor unit installed on patio blocks 100 mm above the ground will spend part of February buried in snow. Wall brackets or a raised base cost a few hundred dollars more and prevent years of reduced performance.

Neglecting the vacuum evacuation

Residual moisture in an R-32 circuit combines with compressor oil and forms acids. The failure does not happen in the first year: it happens in the fifth or seventh.

Forgetting to maintain the indoor filters

The indoor filters of the ORION XLTH+ are washable. Rinsing them with lukewarm water every four to six weeks during the operating season is enough to maintain airflow. We also recommend annual professional HVAC maintenance, including cleaning the indoor coil, condensate pan, and outdoor heat exchanger.

Grants: what applied in this case

The homeowner was replacing an entirely electric heating system, which directed him toward Hydro-Québec’s LogisVert heat pump component, whose eligibility is based in part on the unit’s efficiency ratings and ENERGY STAR certification—two criteria that the ORION XLTH+ meets. Homeowners replacing an oil, propane, or natural gas system generally turn to Chauffez vert, and a federal interest-free loan for energy-efficient renovations may also be added to the financing plan.

The amounts, criteria, and deadlines for these programs are revised periodically. We therefore confirm the eligibility of the exact model at the time of the quote and provide the technical documents required for the application. We include this step in our support because a transcribed model number is all it takes for a complete application to be denied.

The result, two months later

We called the client back at the end of July, after three episodes of extreme heat. The second floor held at 23 °C without the unit needing to run above medium speed. His most useful comment for us was that he could hear the outdoor unit only when he opened the laneway-facing window, and his downstairs neighbour had not reported anything.

The real verdict will come in January. That is also why we document our installations: we know what our equipment does in February because we monitor it.

Why Montreal clients trust us with this type of project

At AirGreen, we have been installing wall-mounted heat pumps, central systems, and multi-zone solutions in Greater Montreal for more than twenty years. Our teams work every day in Rosemont–La Petite-Patrie, the Plateau, Villeray, Ahuntsic, Laval, Longueuil, the North Shore, and the South Shore. We know the laneways, stone foundations, shared walls, and borough regulations because we work there every day.

Every HVAC installation we complete includes a load calculation, equipment selection justified by the figures, documented commissioning, and complete support with rebate applications.

If you are considering a wall-mounted heat pump for a duplex, triplex, condo, or single-family home, email us at sales@airgreen.ca or call us at (514) 316-2973. We come to your property, take measurements, and provide you with a clear quote that includes the exact model number and the proposed unit’s actual performance ratings.