GENERAL AIRSTAGE ALTAIR 300 Mini Split | 12,000 BTU | Montreal, Laval, South Shore, North Shore

GENERAL AIRSTAGE ALTAIR 300 12,000 BTU: the Fujitsu Mini Split Heat Pump under its new name, for a finished basement in Mascouche or Repentigny, cool in summer and supplementally heated in winter, with no ductwork

A finished basement lives the opposite way from the rest of the house. In July, it is the least hot room, but the air there is heavy, sticky, with that musty smell that comes back as soon as the door is closed; in January, it is the coldest room at floor level, and the baseboards run for a long time for middling comfort. Neither the central system, when there is one, nor a window air conditioner, often impossible to fit in a basement window, really settles those two seasons. A mini split does, with no ductwork, through a single hole, and that is the use for which we propose the GENERAL AIRSTAGE ALTAIR 300 12,000 BTU in Mascouche and Repentigny homes.

This machine is the Fujitsu AIRSTAGE ALTAIR 300 12,000 BTU, identical: same indoor unit ASUH12KNAS, same outdoor unit AOUH12KNAS1, same AHRI certificate 217505656, same values certified by NEEP, same warranty of 12 years on the compressor, 12 years on parts and 6 years on labour. Its manufacturer was called Fujitsu General Limited; it has been called GENERAL Inc. since January 1, 2026. Nothing else moved.

GENERAL or Fujitsu AIRSTAGE: the same machine

Paloma Rheem Holdings, owner of Rheem since 1988, acquired Fujitsu General in August 2025, and on January 1, 2026 Fujitsu General Limited became GENERAL Inc. The Fujitsu brand is being phased out of the equipment; during the transition, the same machine is sold under both names. The head office and the R&D centre remain in Kawasaki, Japan, with the same factories, the same AIRSTAGE products, the same model numbers and the same warranty program. The GENERAL trademark has been in use since 1946; the company, founded in 1936, marks the 90th anniversary of its founding in 2026. In Canada, Rheem Canada has handled sales since February 2026; Groupe Master remains AirGreen's distributor.

We show both pages because you will see both names for a while yet, in quotes as on boxes, and you need to be able to check that they designate the same machine. The table below does that, specification by specification.

The twin page under the original name: Fujitsu AIRSTAGE ALTAIR 300 12,000 BTU. Same units, same certificate, same warranty.

Summer in a basement is a matter of humidity before it is a matter of degrees. In air conditioning mode, the wall unit cools the air passing over its coil and condenses the moisture out of it, which leaves through the drain; the air comes out drier, and that is what makes the musty smell and the clammy feel on the family-room sofa disappear. The SEER2 of 18.0 measures efficiency over the cooling season, the EER2 of 10.35 that of heat-wave days at full load. What matters most in a basement is the ability to run at low speed for a long time: a unit that cools too fast and stops leaves the humidity in place. This one modulates very low, down to 1,400 BTU/h in heating at −15 °C and 3,100 BTU/h at 8 °C, and the same modulation lets it, in summer, hold the setpoint without on-off cycling and keep drying the air.

In winter, the basement has an advantage: buried for a good part below ground level, it loses less heat than a floor exposed to the wind, and its need is smaller and steadier. The values certified by NEEP under AHRI certificate 217505656 give the measure of what the ALTAIR 300 brings there. At −8 °C, it delivers 7,500 BTU/h at its certified operating point with a COP of 2.62: every kilowatt-hour consumed returns 2.62 kilowatt-hours of heat, against one for the baseboard. At −15 °C, its certified capacity is 8,200 BTU/h, 68% of its nominal 12,000 BTU size, with a COP of 2.18. The manufacturer guarantees heating down to −15 °C. For a family room or a basement office, that means the heat pump keeps the room comfortable on most winter days and the baseboards start only in deep cold. The HSPF2 of 9.0 sums up the efficiency over the season; it is a modest value next to the cold-climate series, and that is why we present this model as supplemental heating, not as primary heating.

Silence, too, is a basement matter: that is where the teenager's bedroom, the home theatre and the work-from-home office end up. The indoor unit runs between 20 and 41 dB(A) depending on fan speed; at low speed, at night or during a movie, you do not hear it. The outdoor unit holds at 48 dB(A). The vertical louvers are motorized and sweep the air up and down; the horizontal louvers are set by hand at installation, to aim the air toward the centre of the room rather than at the wall.

Installing a wall unit in a basement calls for three decisions that we make with you at the estimate visit:

• The line route: the head mounts high, near the ceiling, on an exterior wall if possible, and the insulated 1/4 and 3/8 in copper refrigerant line exits through the rim joist, above ground level, with the control cable and the drain, protected by a line cover outdoors.
• Drainage: in a basement, the unit is often too low for condensate to flow by gravity to the outside; we then install a discreet condensate pump, or we route the drain to an existing floor drain, and we tell you before the work, not after.
• The outdoor unit: on a wall bracket, raised above accumulated snow, away from bedroom windows, with clearance for air and defrost water.

A licensed electrician connects the dedicated 208/230 V circuit to the panel, which is generally a few steps away, in the basement precisely. We finish with the nitrogen leak test, the vacuum, the start-up and the supply-air temperature check. The refrigerant is R-32, and Wi-Fi is offered as an option, handy for starting the basement's dehumidification from upstairs.

Maintenance is simple, but the basement makes it a little more frequent: dust from the laundry room, the workshop or the dryer clogs the filters faster than upstairs. The indoor filters pull out by hand, rinse under warm water and go back in once dry. Once a year, a refrigeration technician cleans the coil and the drain pan, checks the refrigerant charge and tests the condensate pump if there is one. These are the same steps and the same parts as for the Fujitsu version.

Two clarifications, without detours: this model is not ENERGY STAR certified and it is not listed among the heat pumps eligible for Hydro-Québec's LogisVert program, according to the list of October 27, 2026. We therefore promise you no grant. If a grant is part of your calculation, we will show you the series that qualify.

This model is made for the finished basement of a Mascouche or Repentigny home where you want a dry, cool family room in summer and a comfortable living space in winter without relying on the baseboards, for the bedroom or office in a half-basement, and for the basement apartment of an owner-occupant who wants to offer air conditioning without ductwork or heavy work.

Free quote in Mascouche, Repentigny and across the North Shore

Call us at 514 316-2973 or request your free quote online. Our estimator comes to see the basement, the available wall, the rim joist, the drain route and the electrical panel, and then you receive a written quote. We install the GENERAL AIRSTAGE ALTAIR 300 12,000 BTU on the North Shore, in Laval, in Montreal, in Longueuil and on the South Shore.

An RBQ-licensed HVAC contractor and AIRSTAGE Elite Plus installer, AirGreen installs and services this machine under both names, with the same warranty and the same service.