GENERAL AIRSTAGE CENTAURI R32 Electric Furnace | 3 Tons - 36000 BTU

GENERAL AIRSTAGE CENTAURI AMUH36KUAS 36,000 BTU electric furnace: the Heat Pump heats, the backup waits its turn

This 36,000 BTU (3-ton) electric furnace does not heat like the one sitting in your basement. The AMUH36KUAS multi-position air handler takes its place on the duct system, but the heat comes first from the heat pump, the AOUH36KUAS1 outdoor unit. The pair is identical, screw for screw, to its twin sold under the Fujitsu AIRSTAGE name: the manufacturer is the same, renamed GENERAL Inc. on January 1, 2026, and so are the spec sheet and the warranty.

Every time we visit to replace an electric furnace, someone asks what happens to the heating elements. The old ones leave with the old furnace, but their job stays: the electric backup heat kit, housed in the air handler, takes it over. It stays in reserve as long as the heat pump is enough. The real tuning work is deciding when, and under what conditions, that reserve comes into play.

GENERAL or Fujitsu AIRSTAGE: the same machine

If the cabinet carries a different name, it is because the manufacturer changed hands. Rheem's parent company since 1988, Paloma Rheem Holdings, acquired control of Fujitsu General Limited in August 2025; on January 1, 2026, the Japanese company adopted the name GENERAL Inc., and its American subsidiary changed its name the same day. The designs, the factories and the AIRSTAGE model numbers did not move.

The Fujitsu brand is fading out gradually, so both labels still share distributors' shelves. That is why we publish both pages: the table lines them up, value by value, and you simply keep the name you prefer.

The Fujitsu version of this system is here: Fujitsu AIRSTAGE CENTAURI 36,000 BTU electric furnace.

Here is what actually changes in the basement. The old furnace comes out. In its place, the AMUH36KUAS (21 × 21 × 48 in., W × D × H) takes over the existing supply plenum and return air, once the ducts have been checked during the visit. The room grilles stay where they are. What gets added: outside, the outdoor unit, mounted on a pad or a bracket, and, to connect the two units, a 3/8 and 5/8 in. refrigerant line that runs together with the cable and the drain. An electric furnace never had to get rid of water; the air handler, on the other hand, collects condensate in summer and needs a way out for it. If needed, it can also be mounted downflow (UTD-DFMMB1 kit) or horizontally, left or right.

In winter, the system follows a well-defined sequence:

1. Mild weather: the heat pump heats on its own. The Inverter compressor slows down or speeds up with demand; at 8.3 °C, the brochure gives it 38,000 BTU of rated heating, modulating from 9,200 to 43,000 BTU.
2. Real cold: the heat pump keeps carrying the house. The certified tests give two separate reference points, each to be taken for what it is: 27,400 BTU with a COP of 2.85 at −8 °C, and 32,000 BTU with a COP of 2.18 at −15 °C.
3. Demand above what the heat pump delivers: the backup kit comes into play, according to the backup logic selected at commissioning.
4. Colder than −21 °C: you are outside the outdoor unit's operating range, which the brochure describes as running with no low-temperature lockout down to that limit. The electric backup then takes over.

Choosing that logic matters more than any other setting. Among the backup heat logics the air handler offers, we look for the one that strikes the right balance: the heat pump doing most of the season, and the backup arriving early enough that the house does not lose ground during a cold snap. The kit is a manufacturer accessory, sold separately, that needs its own power supply; before proposing one, we look at the electrical panel and at the old furnace's circuit.

That leaves everything orbiting the furnace, starting with the air exchanger and the humidifier that are often grafted onto it. The built-in input/output terminals of the AMUH36KUAS link them to the air handler, instead of letting each one run on its own schedule. The exchanger (HRV or ERV) and the humidifier connect there, and so can, if needed, a third-party auxiliary heater, a fire alarm or a door switch. During the visit, we note how each one is tied into the furnace today, so we can recreate the same links on the new unit.

On AHRI certificate 217290596, you read a SEER2 of 17.6, an HSPF2 of 9.8 and an EER2 of 10.6. The system is ENERGY STAR cold climate certified under ID 4428949. And it cools, which your electric furnace never did: the brochure lists 36,000 BTU of rated cooling across a 9,600 to 39,000 BTU range, and the spec sheet puts dehumidification at 3.82 pints/h.

With its 1,207 CFM maximum airflow and an allowed external static pressure of 0.2 to 0.8 in. WC, the air handler tells you what your ducts will have to carry; their routing and the number of grilles are decided on site. The air handler runs at 31 dB(A) at its lowest speed and 46 dB(A) at maximum. As for the AOUH36KUAS1, it shows 56 dB(A) and its cabinet measures 31 × 12.63 × 37 in.

The refrigerant line limits leave room to work: 50 m (164 ft) at most, 20 m (66 ft) of it covered by the precharge, 5 m (16 ft) at least and 30 m (98 ft) of maximum height difference. The heat pump connects to a circuit of its own, at 208/230 V (MCA 25 A, MOP 25 A), and the kit to its own. The filter stays reachable through an access panel, and starting up the system, the commissioning, is a refrigeration technician's job. AirGreen, an HVAC contractor holding an RBQ licence, is an AIRSTAGE Elite Plus installer.

No control comes with the unit. If your 24 V wall thermostat can run a heat pump and its backup, the UTY-TTRXZ1 interface lets you keep it. Otherwise, three routes: a KAGAMI UTY-RVRU or UTY-RNRUZ5 wired wall controller, Wi-Fi through the AIRSTAGE Mobile app, or a wireless remote with its IR receiver kit; compatible controllers add service monitoring.

Among the options is a filter base (20 × 20 in.); leak detection, for its part, comes built into the unit. One difference from the old furnace: this system also works in summer, so the filter gets dirty over two seasons instead of one.

As of October 27, 2026, Hydro-Québec listed this system in its LogisVert program for a $3,288 grant; the list in force when you apply is the one that counts. The manufacturer's warranty runs 12 years on the compressor and parts; labour, 6 years. We also offer this same system under the "central heat pump" name.

This size is aimed at the family home heated by an electric furnace with ducts in good shape, especially when an air exchanger or a humidifier is already connected. A house heated by baseboards, with no ducts at all, is not the right starting point. As for the 3 tons, they are confirmed by a calculation made on site, never by a remote estimate.

Official brochures

The manufacturer's brochures are available as PDF files:

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

Tétreaultville and all of Montreal: a free quote to replace your electric furnace

From Tétreaultville to the rest of Montreal, and out to Laval, Longueuil, the North Shore and the South Shore, we handle this replacement from the visit to commissioning. The quote is free at 514 316-2973: we come and look at the furnace, the ducts, the electrical panel and where the outdoor unit could sit.

When you call, tell us which rooms stay the coolest in January: that is often where the duct inspection begins.