Central Heat Pump ADD-ON ARCOAIRE HSH6 Premium | 4 Tons - 48,000 BTU (Coil EVD4X 24.5 in.) - R410A

A cool, dry summer throughout the house, through the existing ductsThe 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 HSH6 Premium | 4 Tons - 48,000 BTU (Coil EVD4X 24.5 in.) - R410A pairs the HSH648GKA outdoor unit with the EVD4X48M24A coil.For many homeowners, the project starts in summer: a house that heats well in winter thanks to its electric furnace, but where the bedrooms become hard to bear during heat waves. This pairing adds central air conditioning to the furnace, and the same heat pump then heats in cool weather. This page focuses on summer, the season in which this system changes daily life the most.One outdoor unit for every roomWith an ADD-ON, cool air flows through the ducts and registers already in place. No more window units that block the view and let hot air in around the frame: the compressor and the outdoor fan are outside, and only the furnace blower runs inside the house. Every room served by the duct system is cooled, including those where a wall unit would be hard to place.The air of the whole house also passes through the furnace filter on every cycle. Central air conditioning therefore filters the air all summer long: a good-quality filter, replaced on time, traps part of the dust and pollen that come in through the windows in spring.Humidity, half of the discomfortA humid day feels hotter than a dry day at the same temperature. In cooling mode, the EVD4X48M24A coil cools the air below its dew point: humidity condenses on its fins and flows out through the condensate drain. The house becomes drier, and a moderate set point is then enough to make it comfortable.This dehumidification requires fairly long cycles. That is why we size the heat pump on the house's actual cooling load, and not as big as possible: an oversized unit cools quickly, shuts off and leaves the air clammy. Since the furnace's electric elements cover the deep cold, nothing forces us to oversize the unit for winter.The upstairs bedroomsIn a two-level house, the upper floor concentrates the heat: the roof heats up in the sun, warm air rises, and the bedrooms are often the rooms farthest from the furnace. Three measures help keep them comfortable. Balancing the dampers, which sends more air upstairs in summer. A return upstairs, which brings warm air back to the coil instead of letting it build up. And blinds or curtains closed on windows exposed to the afternoon sun.During the visit, we look at the upstairs duct runs and the returns. If a correction would help, the quote proposes it.The basement and the main floorConversely, the basement stays naturally cool in summer, and it can even become cold and damp if it receives as much air as in winter. Many duct systems have dampers that are adjusted by season: more open downstairs in winter, more open upstairs in summer. We show you which ones to adjust and in which direction, so that the main floor and the basement do not take all of the cool air.During heat wavesAn air conditioning system is sized for the region's usual summer conditions, not for the hottest day of the decade. During a heat wave in Montreal, it is normal for the heat pump to run almost non-stop in the afternoon. A few habits help: keep a steady set point rather than lowering it sharply when you get home, close the blinds on the sunny side, and let the system run from the morning rather than starting it when the house is already hot.The 4-ton size and the HSH6 seriesThe 4-ton size often suits a large two-level house, a heavily glazed two-storey home facing west, or an extended house on the South Shore. These examples are only a guide: insulation, shading and airtightness change the load, which we establish with a room-by-room load calculation.The HSH648GKA unit belongs to the HSH6 series, one of Arcoaire's Premium series. The EVD4X48M24A coil, a 24.5 in. format, is the same as for the other series of this size; it must match the width of the furnace cabinet, with a sheet-metal transition when needed.System ratingsThe pairing of the HSH648GKA 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.The pairing's cooling and heating ratings are given to you in writing with the quote; this page shows none.Winter, alongside the electric furnaceIn cool weather, the heat pump heats alone; when the cold deepens and it is no longer enough, the thermostat brings in the elements of the electric furnace as auxiliary heat. The auxiliary heat threshold is set at commissioning according to the house and your comfort. During defrost, a plume of vapour comes out of the outdoor unit and the furnace's elements may come on briefly. The heat pump's air is less hot than the air from the electric elements, and its cycles are longer: this is normal.LogisVertThis 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 furnaceThe 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.What commissioning sets for summerthe R-410A charge, after the nitrogen pressure test and the vacuum on the refrigerant line set;the furnace blower speed in cooling mode, for airflow that both cools and dries;the condensate drain flow and, where applicable, the operation of the pump;the thermostat's cooling settings;the position of the dampers for the warm season.The outdoor unit, on its stand, is placed away from bedroom windows and roof drip, according to your municipality's rules, with an outdoor disconnect within sight.MaintenanceReplace 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.Before summer, make sure nothing crowds the outdoor unit: tall grass, branches, patio furniture. A clean outdoor coil rejects heat better, and the house benefits on hot days.AirGreen, for the life of the installationA 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 HSH6 Premium | 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.