Central Heat Pump ADD-ON ARCOAIRE HCH6 2 stages | 2 Tons - 24,000 BTU (Coil EVD4X 14.5 in.) - R410A

A two-stage compressor, added to the furnace you keep

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: its electric elements take over in deep cold. The Central Heat Pump ADD-ON ARCOAIRE HCH6 2 stages | 2 Tons - 24,000 BTU (Coil EVD4X 14.5 in.) - R410A pairs the HCH624GKA outdoor unit with the EVD4X24M14A coil.

What sets the HCH6 series apart is in its name: its two-stage compressor. In an ADD-ON installation, this detail has concrete consequences for the choice of thermostat, the settings of the furnace blower and commissioning. This page goes through them, along with what the installation includes.

What "two-stage" means

A single-stage compressor works one way only: it is either running or off. A two-stage compressor has two operating levels, a reduced level and full capacity, and the system chooses according to demand. On a mild day, the reduced level may be enough; when demand rises, the second stage comes in.

This operation is not continuous modulation: there are two levels, no more. But to take advantage of it, the whole chain has to follow, from the thermostat to the furnace blower. That is where the quality of a two-stage ADD-ON installation is decided.

The thermostat has to follow

A furnace-only thermostat cannot control a heat pump, let alone a two-stage heat pump paired with a furnace. The thermostat we install must manage three things: the two compressor stages, the reversing valve that switches the heat pump from heating to cooling, and calling in the furnace's electric elements, as auxiliary heat, when the cold becomes too sharp. An incompatible thermostat can leave the compressor on a single level, which cancels out the point of the series.

The wiring matters too: between the thermostat, the furnace and the outdoor unit, there must be enough conductors to carry each of these signals. We assess it during the visit and add the missing wiring where needed.

The furnace blower and the two levels

In an ADD-ON system, the furnace blower is what pushes the air through the coil. With a two-stage compressor, the airflow must match the level in use: airflow suited to the reduced level, higher airflow at full capacity. Depending on the furnace, these settings are made on its control board or through the wiring of the motor speeds. We check the condition of the furnace, the airflow of its blower and the duct sizes before the quote, and we confirm that the furnace can provide these settings.

Which homes this size suits

The 2-ton size is aimed at mid-sized homes already equipped with a forced-air electric furnace: a bungalow with a basement, a semi-detached house, a roomy townhouse or a modest cottage. With an ADD-ON system, the heat pump is sized first on cooling, since the furnace's elements cover the deep cold. An oversized unit would spend its time starting and stopping, even with two stages.

Insulation, windows, orientation and airtightness change the needs from one house to the next, at equal size. The room-by-room load calculation confirms the size before the quote.

Winter: the heat pump, then the furnace

A heat pump moves heat instead of producing it. In winter, its refrigerant, R-410A, captures heat from the outdoor air and delivers it to the coil. In fall, in spring and through a good part of winter, it heats alone. When the cold becomes too sharp, 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.

Every hour the heat pump heats alone is an hour those elements stay off: that is what lightens the electric furnace's load over the winter. During defrost, the elements can heat for a few minutes so that the air from the grilles stays warm. The moment auxiliary heat comes in is set according to your house, its insulation and your comfort.

In heating, the thermostat follows a sequence: the heat pump's reduced level first, full capacity when demand rises, then the furnace's electric elements once the heat pump is no longer enough. Properly set, this sequence avoids calling auxiliary heat too early on a cool morning, while letting it take over without hesitation when the cold sets in for good.

Summer: cooling and humidity

In summer, a reversing valve flips the cycle and the heat of the house is rejected outdoors. The cold coil also removes humidity from the air, and the condensed water flows through a drain to a floor drain or a pump. On days when the reduced level is enough, the system runs in longer cycles, which helps keep the air dry; during a heat wave, the second stage takes over.

We also check the return air. A closed bedroom without a return stays warmer than the rest of the house, whatever the compressor.

System ratings

The pairing of the HCH624GKA outdoor unit and the EVD4X24M14A 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. No rating figure therefore appears on this page.

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.

Installation by AirGreen

The 14.5 in. coil and the work

• Coil: set on the furnace's air outlet; if the widths do not match, we fabricate a sealed transition. The condensate drain goes to a floor drain or a pump.
• Outdoor unit: on a bracket or a pad, above the snow line, away from roof drips, dryer vents and bedroom windows.
• Refrigerant line: insulated copper, brazing, pressure test and vacuum before the valves are opened.
• Electrical: dedicated circuit, outdoor disconnect and control wiring for both stages and the furnace; we check that the panel can carry both the heat pump and the electric furnace's elements.
• Thermostat: a model compatible with a two-stage heat pump paired with an electric furnace.

Commissioning for each level

At commissioning, we check the refrigerant charge and the airflow at the reduced level as well as at full capacity, in heating as in cooling. We test defrost, the furnace's electric elements coming in and the stage sequence controlled by the thermostat. We then set with you the moment electric auxiliary heat takes over, and show you how to read the screen.

Maintenance and warranty

The furnace filter now works all year: check it every month and replace it according to its format. Keep the outdoor unit clear of snow and leaves. Plan annual HVAC maintenance of the coil, the condensate drain and the electrical connections, in addition to a check of the electric furnace, its elements and its blower. 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 HCH6 2 stages | 2 Tons - 24,000 BTU (Coil EVD4X 14.5 in.) - R410A. We check your electric furnace, your thermostat and your ducts, then confirm the right size and your grant eligibility before signing.

Available while supplies last.