Central Heat Pump ARCOAIRE R4H5S Economy | 1.5 Tons - 18,000 BTU (Air Handler FJMA4X) - R410A
The right-sized central heat pump for a small ducted home
In a home that already has ductwork, a central heat pump handles the cooling of every room and most of the heating, with a single thermostat and no unit visible on the walls. The Central Heat Pump ARCOAIRE R4H5S Economy | 1.5 Tons - 18,000 BTU (Air Handler FJMA4X) - R410A pairs the R4H5S18AKAAA outdoor unit with the FJMA4X18L0AB cabinet, an air handler that takes the place of the old electric furnace and pushes air through the existing duct system.
Its certified ratings are 14.3 SEER2, 12.0 EER2 and 7.5 HSPF2. At 1.5 tons, it is one of the smallest central heat pump sizes: it is meant for homes where a bigger unit would run in short bursts, heat the bedrooms poorly and leave humidity in the air in summer.
The homes that suit 1.5 tons
This size suits compact homes that already have their ducts: a townhouse, a small well-insulated bungalow, a renovated semi-detached house, or the upper floor of a duplex with its own duct system and its own air handler. It also suits recent homes with a tight envelope, where the heating load is often lower than people expect.
Floor area alone does not settle it. Attic and wall insulation, the age of the windows, the orientation of the house and the amount of glazing change the load a great deal. An unrenovated house from the sixties may need the next size up, even if it is small. That is why we run a room-by-room load calculation before proposing a size, rather than copying the size of the old unit.
Why an oversized unit hurts comfort
The habit of choosing "a little bigger, to be safe" dates from the air conditioner era. With a central heat pump, it costs comfort. An oversized unit reaches the set point in a few minutes, stops, then starts again: these short cycles wear the components, leave temperature differences between rooms and shut the cooling off before the coil has removed the humidity. The house is cool, but clammy.
A properly sized system, on the other hand, runs in longer cycles. Air moves through the ducts for longer, rooms far from the cabinet get their share and the coil has time to dry the air. In a small home, the 1.5-ton size is often the one that allows this steady operation, in winter as in summer.
The FJMA4X cabinet, in place of the old furnace
The FJMA4X18L0AB cabinet is the system's indoor unit. It houses the coil, where the refrigerant releases or absorbs heat, and the blower that moves air through the ducts. It goes where the old electric furnace stood, usually in the basement or a utility closet, and connects to the existing supply plenum and return air.
The cabinet can also receive backup electric heating elements. They only come on when the heat pump alone is no longer enough, in deep cold or during a defrost. Their capacity is chosen from the load calculation and the capacity of the electrical panel; we list it in the quote.
How a heat pump heats a home
A heat pump does not produce heat, it moves it. In winter, the refrigerant flows through the outdoor unit and absorbs the heat contained in the air, even cold air. The compressor raises its temperature by compressing it, then the refrigerant releases that heat to the cabinet's coil, and the blower distributes it through the ducts. In summer, a reversing valve turns the circuit around: the heat of the house is sent outdoors.
Because it moves heat instead of producing it with a resistance, a heat pump delivers more energy than it uses as long as the outdoor air is not too cold. The system runs on R-410A, a refrigerant that refrigeration technicians know well.
What the certificate shows for winter
The certificate lists 10,100 BTU/h at -8 °C (17 °F) and 7,700 BTU/h at -15 °C (5 °F), with a COP of 1.88 at -15 °C. The two points are measured separately; we report each one as published, without extrapolating.
Compared with the nominal size of 18,000 BTU, these figures represent about 56% at -8 °C and 43% at -15 °C. A heat pump's capacity drops as the cold deepens, while the home's needs rise. There is therefore an outdoor temperature below which the heat pump is no longer enough on its own: the cabinet's backup elements then supply the missing share, and switch off as soon as the heat pump can carry the load again.
These figures come from certificate AHRI 210998953, as published in the AHRI certification directory.
Reading SEER2, EER2, HSPF2 and COP
- SEER2 (14.3): seasonal cooling efficiency, calculated over a typical summer. The higher it is, the less cooling weighs on the summer bill.
- EER2 (12.0): cooling efficiency at full demand, in hot weather. This is the rating that matters during heat waves.
- HSPF2 (7.5): seasonal heating efficiency. For a home that is heated most of the year, this is the rating to look at first.
- COP: the ratio between the heat delivered and the electricity used at a given temperature. An electric baseboard has a COP of 1; with a COP of 1.88 at -15 °C, the heat pump delivers almost twice as much heat as the electricity it uses, even at that temperature.
These are not the highest ratings available in a central heat pump; they are those of a conventional system at the right size. If seasonal efficiency comes first for you, we will also show you better-rated pairings of comparable size during the visit.
Summer: cooling and humidity
In summer, the same system cools the whole house through the existing grilles. The cabinet's coil cools the air and removes humidity, which flows out through the condensate drain. In a small volume, the right size makes all the difference: cycles are long enough to dry the air, and the house stays comfortable without lowering the set point.
In a townhouse, the upstairs bedrooms are often the warmest rooms. We check that each one has its supply and that there is enough return air upstairs, because a bedroom with the door closed and no return stays warmer than the rest of the house.
LogisVert
This pairing does not carry an amount on Hydro-Québec's LogisVert list of October 19, 2026. If the grant matters for your project, we will point you to an eligible pairing of comparable size and confirm eligibility before signing.
Installation by AirGreen, from the visit to commissioning
The steps of the job
A central heat pump only reaches its ratings if the installation is right. Here is how our jobs unfold.
- Visit and load calculation: we measure the rooms, note the insulation and windows, and confirm that 1.5 tons is the right size.
- Duct check: main ducts, number of registers, return air and filter location. A central heat pump only delivers its full efficiency if the airflow keeps up.
- Indoor cabinet: the FJMA4X takes the place of the old furnace, connects to the plenum and gets a condensate drain to a floor drain or a pump.
- Outdoor unit: on a wall bracket or a stand, above the snow line, away from roof drips and dryer vents.
- Refrigerant connection: insulated copper line set, brazing, pressure test and vacuum before the valves are opened.
- Electrical: dedicated circuit for the outdoor unit, disconnect, power to the cabinet and its backup elements, thermostat wiring.
- Commissioning: check of the refrigerant charge, airflow, defrost and thermostat, then an explanation of how everything works.
Maintenance
A central system needs little maintenance, but it needs it regularly. Check the cabinet filter every month during the heating and cooling seasons, and replace it according to its format: a clogged filter reduces airflow, and therefore efficiency. Keep the outdoor unit clear of snow, ice and leaves, and do not cover it in winter, since it runs all year.
Plan annual HVAC maintenance: cleaning of the coils, check of the condensate drain, the electrical connections and operation in both heating and cooling. In winter, the white vapour rising from the outdoor unit during defrost is normal.
Warranty
Warranty: 10 years on the compressor, 10 years on parts and 6 years on labor.
Keep the invoice and the commissioning report, with the serial numbers of both units: they serve as the reference for any service request.
AirGreen, for the life of the installation
A family business active for more than fifteen years in Montreal, Laval, Longueuil, the North Shore and the South Shore, we hold RBQ licences for ventilation, refrigeration and electrical work and carry $5,000,000 in liability insurance. The in-home assessment is free, the quote is in writing, and our financing options let you choose the right unit rather than the cheapest one.
These three licences match the three parts of a central heat pump job: the ducts, the refrigerant circuit and the electrical connection.
Request your free estimate for the Central Heat Pump ARCOAIRE R4H5S Economy | 1.5 Tons - 18,000 BTU (Air Handler FJMA4X) - R410A. We assess the home room by room and confirm the right size and your grant eligibility before signing.