GENERAL AIRSTAGE CENTAURI R32 Electric Furnace | 4 Tons - 48000 BTU

GENERAL AIRSTAGE CENTAURI AMUH48KUAS 48,000 BTU electric furnace: from the basement up to the bedrooms upstairs

In a two-storey house, the basement electric furnace keeps the whole duct system alive: every grille on the ground floor and upstairs depends on it. This 48,000 BTU (4-ton) GENERAL AIRSTAGE CENTAURI system takes over from it. The AMUH48KUAS multi-position air handler goes in the basement on the same ducts, the AOUH48KUAS1 Heat Pump sits outside, and an electric backup heat kit, housed in the air handler, provides reinforcement on the toughest days.

On the twin Fujitsu AIRSTAGE page, you will find exactly these two model numbers. The manufacturer, Fujitsu General Limited, renamed GENERAL Inc. on January 1, 2026, publishes a single spec sheet for both names and attaches the same warranty to it.

For a house this size, three things matter more than the rest: how much air reaches the upper floor, where the system is controlled from, and the grant. On that last point, this size receives the highest LogisVert amount in the entire CENTAURI series.

GENERAL or Fujitsu AIRSTAGE: the same machine

The name change moved nothing. Since February 2026, Rheem Canada has been in charge of sales in Canada; our orders still go through Groupe Master, the distributor we were already working with. The R&D centre and head office have not left Kawasaki, Japan, and AirGreen remains an AIRSTAGE Elite Plus installer.

If you still see "Fujitsu" on a box or in a warranty document, that is normal: the brand is being withdrawn in stages. We keep both pages online to avoid any confusion, and the following table lines up their values, identical from top to bottom.

You can also look at the Fujitsu AIRSTAGE CENTAURI 4-ton electric furnace, its twin under the former name.

When the furnace is replaced, almost the entire duct system stays: the main trunk running under the basement joists, the branches, the risers going up to the second floor and the grilles in every room. The old furnace is removed, and the AMUH48KUAS, whose cabinet measures 21 × 21 × 48 in. (W × D × H), connects to the supply plenum and the return air. In a basement, it normally goes in upflow; nothing prevents installing it downflow (UTD-DFMMB1 kit required) or in a horizontal left or right position, when the room calls for it.

The real test is the second floor. The AMUH48KUAS blower can move 1,600 CFM, against an external static pressure that the manufacturer places between 0.2 and 0.8 in. WC. That high airflow is only worth something if the ducts let it climb to the bedrooms. That is why the visit, where the duct layout and the number of grilles are set, reviews:

• the main trunk and its branches, from the basement to the farthest rooms;
• the risers climbing to the second floor inside the walls, sometimes narrow for the target airflow;
• the upstairs return air grilles, essential for air to circulate instead of sitting stagnant in the bedrooms;
• the location of the wall control, which must read a temperature representative of the house;
• the electrical service and the circuit the furnace used, since the heat pump and the backup kit will each have their own.

Let's talk capacity, since it is what has to take over from the old furnace. The brochure breaks it down this way: in cooling, 45,500 BTU rated, modulating from 15,400 to 48,000 BTU; in heating, 51,000 BTU rated at 8.3 °C, modulating from 16,000 to 55,000 BTU. For the whole CENTAURI line, the manufacturer goes further and claims rated heating capacity that can exceed nominal capacity by up to 33%. In winter, the certified tests provide two separate points, presented as they are: 37,200 BTU, COP of 2.99, at −8 °C; 41,000 BTU, COP of 2.24, at −15 °C.

The AOUH48KUAS1 heats and cools down to −21 °C, and the brochure states "no lockout" at low temperature. In a large house, the backup heat kit is what makes the difference on the coldest nights and below that limit. The air handler offers several backup logics, which the refrigeration technician sets at commissioning; the compatible kit from the manufacturer, bought separately, gets its own dedicated supply, in addition to the 208/230 V heat pump circuit (MCA 30 A, MOP 30 A).

The control deserves early thought, because none ships with the unit. In a multi-storey house, a wired wall controller, the KAGAMI UTY-RVRU or the UTY-RNRUZ5, keeps the control where the family is used to finding it, at the old thermostat's location if the spot is suitable. With the AIRSTAGE Mobile app, optional Wi-Fi also lets you adjust the setpoint from upstairs, without going down. A third-party 24 V thermostat can also connect through the UTY-TTRXZ1 interface, and a wireless remote works with its IR receiver kit. Service monitoring, finally, goes through a compatible controller.

Down in the basement, the air handler stays at 34 dB(A) on low and reaches 51 dB(A) at full airflow. As for the outdoor unit (31 × 12.63 × 37 in.), its spec sheet shows 59 dB(A); we keep it away from bedroom windows, yours upstairs as well as the neighbour's. On the piping side, the refrigerant line (3/8 and 5/8 in.) can stretch to 75 m (246 ft); the precharge covers the first 30 metres (98 ft), the minimum length is 5 m (16 ft) and the allowed height difference reaches 30 m (98 ft): the unit can go in the backyard rather than against the mechanical room wall. The cable and drain follow the line, and the unit rests on a pad or a bracket.

In summer, it is the second floor again that benefits most, since it is where heat builds up. The same ducts then deliver cooled air, with dehumidification of 4.7 pints/h according to the spec sheet. The values on AHRI certificate 217290597: a SEER2 of 17.0, an HSPF2 of 9.6 and an EER2 of 9.5, for an Inverter compressor running on R-32. The system also holds ENERGY STAR cold climate certification, under ID 4428950.

An access panel is built in for maintenance. The filter can sit on the optional 20 × 20 in. base, and it deserves watching: a loaded filter slows the air, and the rooms farthest from the unit are the first to notice. Leak detection is part of the air handler.

For the grant, Hydro-Québec gave this system $4,464 in its LogisVert list of October 27, 2026, the highest amount in the CENTAURI series; the list in force on the date you apply is the one that counts. Warranty: 12 years from the manufacturer on the compressor and parts, 6 years on labour. AirGreen also offers it under the "central heat pump" name, with no technical difference at all.

This system suits the two-storey house whose ducts already serve both levels. If the second floor is heated by baseboards and has no grilles, the air handler will not be able to heat it without new ducts, and we assess that possibility with you. Finally, the 4 tons have to come out of the calculation made on site; if it points lower, we will propose a smaller system.

Official brochures

The manufacturer's brochures are available as PDF files:

• Brochure in French (PDF)
• Brochure in English (PDF)

Laflèche, in Saint-Hubert: a free quote for your two-storey home

Laflèche, the rest of Saint-Hubert, all of Longueuil: we install this system there in place of an electric furnace, and our territory also covers Montreal, Laval, the North Shore and the South Shore. For a free quote from AirGreen, an HVAC contractor, call 514 316-2973; it starts with a visit of the basement, both floors and the yard.

Before we come, locate the return air grilles upstairs, if there are any. Their number and size tell us a lot about what the duct system will be able to do.