Central Heat Pump ADD-ON ARCOAIRE R4H5S Economy | 3 Tons - 36,000 BTU (Coil EVD4X 17.5 in.) - R410A

Three tons of cooling and heating, on an electric furnace that stays in service

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 is only used as backup, through its electric elements. The Central Heat Pump ADD-ON ARCOAIRE R4H5S Economy | 3 Tons - 36,000 BTU (Coil EVD4X 17.5 in.) - R410A pairs the R4H5S36AKAAA outdoor unit with the EVD4X36M17A coil.

The R4H5S series is the entry level of this Arcoaire family. At 3 tons, it is aimed at roomy homes, and the outdoor unit becomes a visible part of the property: where it goes, how it gets through winter and how it is connected matter as much as the equipment itself. This page takes the time to cover them.

What the system includes

Inside, the coil sits on the furnace's air outlet and the furnace blower pushes the air through it, then into the existing ducts. Outside, the unit contains the compressor and the heat exchanger that capture or reject heat. An insulated copper line connects the two, and the circuit runs on R-410A. A compatible thermostat coordinates the heat pump and the furnace's elements. Those elements and their power supply are not touched: they stay in place for backup.

Which homes this size suits

The 3-ton size is aimed at roomy homes: a large cottage, a bungalow with a large finished basement, an open-plan house with plenty of windows. With an ADD-ON system, the heat pump is sized first on cooling needs, since the furnace's elements cover the deep cold. A well-insulated house, even a large one, is sometimes fine with the next size down; an oversized unit would run in short cycles and leave humidity in the air. The room-by-room load calculation confirms the size.

The furnace must keep up too. A 3-ton coil requires substantial airflow, and we check the condition of the furnace, the airflow of its blower and the duct sizes before the quote.

Heat pump and furnace through the seasons

A heat pump moves heat instead of producing it: in winter, it captures heat from the outdoor air and delivers it to the coil; in summer, a reversing valve flips the cycle. In fall, in spring and through a good part of winter, the heat pump heats alone. When the cold becomes too sharp for it, the thermostat brings in the furnace's electric elements as auxiliary heat. This pairing does not carry the cold-climate designation; the furnace's elements cover the coldest nights.

The rest of the time, those elements stay off: the heat pump carries the heating, and the electric furnace only tops it up. During defrost, the elements may heat for a few minutes so that the air from the grilles stays warm. The moment auxiliary heat comes in is set with you at commissioning, according to your house.

Cooling and humidity

In summer, the heat pump cools every room served by the ducts. The cold coil also removes humidity, and the condensed water flows through a drain to a floor drain or a pump. A right-sized unit runs long enough on each cycle to dry the air throughout the house. We check the return air: a closed bedroom without a return stays warmer than the rest of the house.

System ratings

The pairing of the R4H5S36AKAAA outdoor unit and the EVD4X36M17A 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. This page therefore publishes no rating figure.

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. Our page on the grant for efficient heat pumps summarizes the program's conditions.

The installation, from the yard to the basement

Choosing the location

The location of the outdoor unit is decided during the visit, with you. We look for a spot close to the mechanical room, to keep the copper line short, and clear all around, so that air flows freely through the unit and the technician can reach it. We avoid bedroom windows, yours as well as the neighbour's, and corners where the hot air rejected in summer would stay trapped.

In a narrow side yard, the choices narrow. Some municipalities also regulate where outdoor equipment may go, and we take that into account. We present the chosen location to you before the work, so that there are no surprises on the day itself.

Snow, ice and defrost water

A heat pump runs in winter: it must stay above the snow line, on a wall bracket or a raised pad. It must not sit under a gutter or a roof edge that would drench it with meltwater, since that water freezes on the unit. During defrost, the unit also releases water: we choose a spot where it will not form ice on a driveway, a staircase or a walkway. And unlike an air conditioner, the unit is not covered in winter.

Wall bracket or pad: the choice depends on the wall, the yard and the snow that usually builds up in that spot. A wall bracket easily keeps the unit above the snow, but we avoid fastening it to a bedroom wall, so as not to transmit vibration into it. A raised pad, set on the ground away from the wall, is often better in that case.

Refrigerant line and electrical

The insulated copper line goes through the wall via a sealed opening, then reaches the coil by the most direct route. It is brazed, pressure tested and put under vacuum before the valves are opened. Outside, we protect it where it could get snagged.

The unit gets a dedicated circuit and a nearby disconnect, within sight of the unit. During the visit, we check the free space and capacity of the panel, which already feeds the furnace's elements; if work is needed, it appears in the quote. The control wiring connects the new thermostat, the furnace and the outdoor unit.

In the basement: the 17.5 in. coil and commissioning

The 17.5 in. coil is set on the furnace's air outlet; if it does not line up with it, we fabricate a sealed transition. We measure the clearance above the furnace and identify any humidifier mounted on the plenum. The condensate drain goes to a floor drain or a pump, with a steady slope. At commissioning, we check the refrigerant charge, airflow, defrost and the furnace's elements coming in, then we explain the thermostat to you.

Maintenance and warranty

The furnace filter now works all year: check it every month and replace it according to its format. After a storm, clear the snow around the outdoor unit and make sure nothing blocks the air; in fall, remove the leaves. Plan annual HVAC maintenance of the coil, the condensate drain and the electrical connections, in addition to a check of the electric furnace and its elements. In winter, white vapour during defrost is normal.

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

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 | 3 Tons - 36,000 BTU (Coil EVD4X 17.5 in.) - R410A. We assess the home room by room, choose the outdoor unit's location with you and confirm the right size and your grant eligibility before signing.

Available while supplies last.