A fieldstone wall, a basement workout room, and no ductwork available
The basement of a home in Saint-Rémi, in the Jardins-de-Napierville RCM, had been converted into a workout room a few years earlier: floating floor, mirror panels, squat rack, weight-plate storage rack, and recessed lighting. Everything was there except comfort. In July, the room reached 27 °C by the second set, the air became muggy, and the mirrors fogged up. In January, the opposite was true: 15 °C at floor level, making it impossible to warm up without keeping a coat on for the first ten minutes.
The homeowner called us with a simple request and a major physical constraint: make the room usable twelve months a year without touching the fieldstone foundation wall that runs from one end of the basement to the other.
We installed a FUJITSU AIRSTAGE Orion XLTH+ 12 000 BTU wall-mounted heat pump (indoor unit ASUH12KTAS, outdoor unit AOUH12KTAP1). Here is how the project unfolded, what proved more demanding than expected, and what this case can teach anyone considering an HVAC installation in the basement of an older home in Montréal, Laval, Longueuil, the North Shore, or the South Shore.
Why a wall-mounted unit rather than a central system
The house was already heated with electric baseboard heaters. There was no existing ductwork, no plenum, and no proper mechanical space in the basement. Adding a central system would have meant building a complete ductwork network in a room with limited ceiling height, losing 20 cm of ceiling clearance over half the area—in a room where people lift weights overhead.
The wall-mounted heat pump met three needs simultaneously:
- Air conditioning and dehumidification in summer, with moisture removal of 1.8 L/h on this model—an especially important feature in a room where two people work out with the door closed;
- Efficient heating in winter, almost completely replacing the basement baseboard heaters;
- Just one wall penetration, meaning only one intervention on the envelope of an older home.
The selected unit: FUJITSU AIRSTAGE Orion XLTH+ 12KTAP1
The choice of model is anything but trivial. The Orion XLTH+ series is FUJITSU AIRSTAGE's cold-climate range, and it stands out precisely where conditions are most challenging in Montérégie.
| Feature | Value (12KTAP1) |
|---|---|
| Rated cooling | 12,000 BTU/h (range 3,100 to 17,300) |
| Rated heating | 15,300 BTU/h (range 4,500 to 27,300) |
| SEER2 (TRÈS2) | 31,5 |
| HSPF2 Region V (CPSC2) | 11,3 |
| EER2 (TRE2) | 16,7 |
| COP (CP2) | 4,88 |
| Heating range | −30 °C to 24 °C |
| Refrigerant | R-32 (GWP 675) |
| Indoor sound level | 23 dB(A) in Quiet mode |
| Certification | ENERGY STAR (ES, ESCC, ESME) |
The figure to remember for a Quebec basement is not SEER2, but residual heating capacity in cold weather. The 12KTAP1 delivers 171% of its rated capacity at −15 °C, 156% at −21 °C, 128% at −26 °C, and 103% at −30 °C. In other words: on the coldest night of the year in Saint-Rémi, the unit still produces more than its nominal 15,300 BTU/h. Many wall-mounted heat pumps sold in Quebec lose 40 to 50% of their capacity at −20 °C—that is exactly when the customer starts looking at it skeptically.
The outdoor unit also incorporates a base pan heater, a detail we require for any installation where snow accumulates on the ground against the house.
The stone wall: the real obstacle on the project
The first photo tells the whole story. The fieldstone pillar occupies the corner where, on paper, the indoor unit should have gone. Drilling through a lime-mortared stone foundation is no minor operation: core drilling vibrates the assembly, and a stone that becomes dislodged inside the wall cannot simply be put back in place.
Our approach was to move the unit onto the adjacent stud partition wall, built in front of the highest section of the foundation, and route the piping through the rim joist above the level of the stone. Three advantages:
- No structural work on the original masonry;
- An outlet above the exterior ground level, protected from accumulated snow and spring water backflow;
- A short piping run, well below the model's 20 m limit (factory precharge up to 14.9 m, so no refrigerant addition was necessary).
The indoor unit was mounted approximately 2.25 m above the floor, in the corner opposite the window. This height had a precise purpose: above the line of the mirrors, to prevent the airflow from being directed straight back toward the unit and skewing the ambient temperature reading.
The condensate drain: the step too many people underestimate
In the basement, condensate does not drain by gravity to the outside—the outlet is higher than the unit. A quiet condensate pump is therefore required, connected to an existing drain or the sump pit. On this project, the line was routed along the window frame and then down to the floor drain, with a trap and an overflow pipe.
A 12,000 BTU wall-mounted heat pump in cooling mode in a workout room can generate more than a litre and a half of water per hour of sustained operation. An improvised connection into a pan always ends the same way: a swollen floating floor.
The outdoor unit and snow clearance
The AOUH12KTAP1 unit measures 716 × 820 × 315 mm and weighs 42 kg. It was installed on wall brackets with anti-vibration pads rather than on a ground slab, approximately 45 cm above the average snow level. On the South Shore, where late-January accumulations regularly exceed 60 cm, wall mounting prevents the defrost grille from being buried and cold air from recirculating beneath the unit.
The electrical connection was made on a dedicated 208-230 V / 60 Hz / single-phase circuit with a 20 A circuit breaker, run from the main panel. The outdoor sound level of 48 dB(A) in cooling mode allowed us to comply easily with the usual setback distances from the property line—a point we systematically verify with the municipal planning department before every HVAC installation.
The process, hour by hour
- 7 h 45 — Arrival, protection of the floor and mirrors, and final confirmation of the location with the client.
- 9 h 00 — Mounting of the wall plate, drilling the passage through the rim joist, and installing and sealing the sleeve.
- 10:30 a.m. — Installation of the outdoor unit on brackets, bending and flaring of the piping (3/8 in. gas, 1/4 in. liquid).
- 12:30 p.m. — Electrical connection, condensate line, and installation of the condensate pump.
- 14 h 00 — Evacuation, leak check, and opening of the valves.
- 3:15 p.m. — Start-up, pressure checks, configuration of the built-in Wi-Fi and the AIRSTAGE app.
- 4:00 p.m. — Explanation of how it works, demonstration to the client of how to clean the washable indoor filters, and handover of the documents.
One day. No ductwork, drywall repair, or stone moved.
Mistakes to avoid in a basement
- Undersizing because you think “basement = cool”. A workout room has a high internal heat gain: people, lighting, and sometimes a television. The load is nothing like that of a bedroom of the same size.
- Sizing up by reflex. An oversized unit reaches the setpoint too quickly and stops dehumidifying. In a closed room, this is the fastest way to end up feeling clammy despite a thermostat setting of 21 °C.
- Installing the unit facing a mirrored wall or less than 15 cm from the ceiling. Manufacturer clearances exist for a reason: air returns through the top.
- Neglecting to seal the wall penetration. In an older home, a poorly sealed penetration becomes a path for cold air and an entry point for vermin.
- Failing to verify municipal compliance. Noise and placement rules vary from one municipality to another across Montreal, Laval, Longueuil, the North Shore, and the South Shore.
Applicable grants
The Orion XLTH+ series is ENERGY STAR certified, including the cold-climate (ESCC) and highest-efficiency (ESME) designations. This certification is an eligibility requirement for most Quebec financial incentives, notably Hydro-Québec's LogisVert and Rénoclimat. Amounts and criteria change from year to year; at AirGreen, we verify each unit's eligibility at the time of quotation and provide the documents required for the application.
What this Saint-Rémi project reminds us
An older home does not conform to a plan. The stone wall does not move, the drain is where it is, and the window occupies the most logical wall. What distinguishes a successful HVAC installation from an acceptable one is understanding the building before drilling the first hole.
Our approach
At AirGreen, every project begins with a technical visit during which we measure, photograph, and validate three things: the actual piping route, condensate management, and available electrical capacity. We refuse to set a price over the phone based solely on square footage — that is how you end up with a poorly placed unit and a disappointed customer.
We serve all of Montreal, Laval, Longueuil, the North Shore, and the South Shore, including Saint-Rémi, Saint-Constant, Candiac, Delson, Sainte-Catherine, Napierville, and Saint-Isidore. Our teams are certified, hold RBQ licences, and are trained on the FUJITSU AIRSTAGE product lines.
Ready for your project
If you are considering a wall-mounted heat pump for a basement, an addition, a finished garage, or a room your current system does not reach, write to us or call us. We will provide sizing based on your building, a clear price including installation, and complete support with your grant applications.
AirGreen — Air Conditioning & Heating
(514) 316-2973 | sales@airgreen.ca