Central Heat Pump ADD-ON ARCOAIRE R4H5S Economy | 4 Tons - 48,000 BTU (Coil EVD4X 24.5 in.) - R410A

The heat pump heats first, your electric furnace backs it up

The ADD-ON system adds a heat pump to an existing electric furnace: a coil is installed on the furnace and the outdoor unit heats and cools through the same ducts. The furnace's electric elements are only used as backup. The Central Heat Pump ADD-ON ARCOAIRE R4H5S Economy | 4 Tons - 48,000 BTU (Coil EVD4X 24.5 in.) - R410A pairs the R4H5S48AKAAA outdoor unit with the EVD4X48M24A coil.

The principle of an ADD-ON does not change from one house to the next: the heat pump heats as long as it is enough, the electric furnace's elements take over when the cold demands it, and in summer the heat pump cools the whole house. What changes is the furnace in place: its age, its blower, its control and the electrical panel that feeds it. Here is what each of these points calls for.

What is inside an electric furnace

An electric furnace is a simple piece of equipment: a blower pushes the house air across heating elements, resistances similar to those of an electric baseboard, and the heated air goes out into the ducts. The elements are grouped, and the furnace control turns them on one after the other according to demand, rather than calling for all the power at once.

In an ADD-ON, none of this disappears. The coil is added on the air outlet, the furnace blower pushes air through it summer and winter, and the elements stay ready to serve. A heat pump moves heat rather than producing it: it captures heat from the outdoor air and carries it to the coil. As long as it is enough, the elements stay idle.

Who heats, and when

In mild and cool weather, the heat pump heats alone. When the cold deepens and it can no longer hold the set point, the thermostat brings in the furnace's elements as auxiliary heat. In deep cold, they carry most of the heating. During the outdoor unit's defrost cycles, they may also come on briefly so that the air at the registers stays warm.

This sharing happens without any action on your part: you set a temperature, and the thermostat chooses the source. An emergency heat mode also lets the elements heat on their own if the outdoor unit has to be shut down for a repair; the house stays heated in the meantime.

The electrical panel and the service entrance

Here, both pieces of equipment are electric. The outdoor unit adds a dedicated circuit to the panel that already feeds the furnace and its elements. Before the quote, we check the capacity of the electrical service and the space available in the panel; if a modification is needed, the quote specifies it.

We also look at the condition of the wiring and the breaker of the furnace itself. Connections that have overheated or tired original wiring are easier to correct during the project than afterwards, and our electrical licence lets us handle them as part of the same project as the heat pump.

The thermostat and the auxiliary heat setting

The thermostat links the two pieces of equipment. It is a heat pump thermostat, sometimes connected to an outdoor sensor, which calls on the heat pump first, then on the elements when the house needs more. The point at which auxiliary heat comes in is set according to the heat loss of the house and your comfort; we set it at commissioning and show you how to change it.

Auxiliary heat that comes in too early makes the elements work when the heat pump would have been enough; auxiliary heat that comes in too late lets the house cool down before the elements help. The setting looks for the right balance for your home, and it can be adjusted after the first cold spells if the house calls for it.

The air delivered by the heat pump is less hot than the air from the electric elements, the cycles are longer, and a plume of vapour comes out of the outdoor unit during defrost. This is normal operation.

The 4-ton size and the Economy series

The 4-ton size often serves a large family home: a two-storey house with a finished basement in Laval, an extended two-level house, a heavily glazed house. These examples are only a guide; a room-by-room load calculation settles it. We size the heat pump on the cooling load, since the furnace's elements cover the deep cold, which avoids the short cycles of an oversized unit.

The EVD4X48M24A coil is a 24.5 in. format and must match the width of the furnace cabinet, with a sheet-metal transition when needed. The R4H5S48AKAAA unit belongs to Arcoaire's Economy series; the same coil goes with the other series of this size, and it is the ratings of the pairing, confirmed before the quote, that let you compare them.

System ratings

The pairing of the R4H5S48AKAAA outdoor unit and the EVD4X48M24A coil is not listed with SEER2 ratings in the AHRI certification directory. We confirm the ratings of the complete system before the quote; they also determine grant eligibility.

Together with the load calculation, these ratings are also used to set the point at which the thermostat adds the furnace's elements. You receive them in writing with the quote; this page shows none.

In summer, the furnace only lends its blower

In summer, the furnace's elements stay off and only its blower works. The heat pump cools the whole house through the existing ducts, and the coil removes humidity from the air, which drains through the condensate line to the floor drain or a pump. For a house heated by an electric furnace alone, without central air, this is often the most noticeable change of the project.

The furnace blower must then deliver the airflow the coil requires. We check its capacity and set its cooling speed at commissioning.

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.

Installation on the existing furnace

The coil sits on the furnace's air outlet, and a compatible thermostat decides when the heat pump heats alone and when the electric furnace takes over. We check the condition of the furnace, the airflow of its blower and the duct sizes before the quote. The outdoor unit goes on a stand, above the snow line, on a dedicated circuit.

The insulated refrigerant line set connects the outdoor unit to the coil; its joints are brazed under nitrogen, then it undergoes a pressure test and a vacuum before the R-410A charge. The outdoor unit is placed out of roof drip and away from bedroom windows, according to your municipality's rules, with an outdoor disconnect within sight.

Maintenance: two pieces of equipment, two schedules

Replace the system filter according to its format, keep the outdoor unit clear of snow and leaves, and plan annual HVAC maintenance of the coil, condensate drain and electrical connections. In winter, white vapour during defrost is normal.

The electric furnace keeps its own schedule: inspection of the blower, the heating elements and the tightness of their connections. Plan both maintenance visits before the heating season.

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.

Request your free estimate for the Central Heat Pump ADD-ON ARCOAIRE R4H5S Economy | 4 Tons - 48,000 BTU (Coil EVD4X 24.5 in.) - R410A. We assess the home room by room and confirm the right size and your grant eligibility before signing.

Available while supplies last.

Warranty: 10 years on the compressor, 10 years on parts and 6 years on labor.