Wall-Mounted Heat Pump ARCOAIRE 16.8 SEER | 18,000 BTU - R454B

A plex apartment cooled in summer, and baseboards that heat less

In Montreal duplexes and triplexes, summer is still often spent with window air conditioners: noisy, balanced on the sill, and removed every fall. Whether you live in one of the units or rent one out, a wall-mounted heat pump settles the matter for good. The Wall-Mounted Heat Pump ARCOAIRE 16.8 SEER | 18,000 BTU - R454B cools the apartment's large living space in summer, and heats it in spring, in fall and for a good part of the winter, alongside the baseboards.

Its certified ratings are 18.3 SEER2, 9.9 EER2 and 8.7 HSPF2. It runs on R-454B refrigerant with a variable-speed compressor. The series name carries the mention 16.8 SEER; it is the SEER2 ratings on the certificate that are used to compare units.

Why replace window air conditioners

A window air conditioner blocks the view and some of the light, lets warm air and noise in around the frame, and often drips on the balcony or sidewalk below. It has to be installed and removed every year, and it does not heat. A wall-mounted heat pump puts the compressor outside, frees the window and spreads air up high, across the whole room.

For an owner who rents, it also makes for a more attractive unit: air conditioning is a frequent criterion for tenants, and a heat pump that heats in the shoulder seasons reduces baseboard use, and therefore the occupant's electricity bill.

Which apartment it suits

The 18,000 BTU size suits a large living space: a double living room, a living room open to the dining room, or a kitchen-dining room enlarged during a renovation. In a plex apartment, the bedrooms often open onto a long hallway; a single head will not cool them if their doors stay closed. Depending on the floor plan, we will propose a single head for the living space, or a configuration that also serves the bedrooms. We discuss this during the visit, floor plan in hand.

The ground-floor and top-floor units do not have the same needs either: downstairs, the floor above a cold basement weighs in winter; upstairs, it is the roof that weighs in summer. The load calculation takes this into account, unit by unit.

Summer: cooling and humidity

The SEER2 rating of 18.3 describes cooling efficiency over the whole season, and the EER2 rating of 9.9 describes efficiency on a hot day. Because the compressor slows down as soon as the room approaches the set point, the unit spends most of the summer at low speed, where it uses the least.

Second- and third-floor units accumulate the heat that rises and the heat from the roof. At low speed, the indoor coil stays cold and condenses moisture from the air, which drains away. This continuous dehumidification makes the room comfortable at a reasonable set point, even on hot, humid July nights. Closing the blinds on the sunny side in the afternoon also lightens the load a lot.

Heating, certified figures

The certificate lists 11,200 BTU/h at -8 °C (17 °F), about 62% of the nominal size, with a COP of 2.41, and 10,600 BTU/h at -15 °C (5 °F), about 59%, with a COP of 2.10. The two points are measured separately; we report each one as published.

These figures are clear: the heat pump heats with very good efficiency, but its capacity in deep cold does not replace the baseboards of a whole apartment. It takes care of the fall, the spring and moderate winter days; the baseboards handle the rest. The setting is simple: the heat pump holds the main set point, and the baseboard thermostats are set a few degrees lower. They only switch on when the heat pump needs help.

What to plan for in a plex

In a divided co-ownership building, installing an outdoor unit on the facade or the roof generally requires the co-owners' approval. In a rental building, plan access for annual maintenance and give the tenant the basic instructions: rinse the filters, store nothing in front of the outdoor unit, report any water leak at the drain. These simple steps extend the unit's life and avoid unnecessary service calls. If several units in the building are equipped, we plan the outdoor units' locations together, to keep the yard and facade clear.

Inverter and R-454B refrigerant

A heat pump moves heat instead of producing it: in summer, it takes the heat out of the apartment; in winter, it draws heat from the outdoor air. Inverter technology varies the compressor's speed instead of running all-or-nothing. R-454B is the new-generation refrigerant, with a much lower global warming potential than the previous one; classified A2L, it calls for precise installation methods, which we apply on every job.

The ratings, plainly

• SEER2 of 18.3: cooling efficiency over the whole season.
• EER2 of 9.9: cooling efficiency at the hottest point.
• HSPF2 of 8.7: heating efficiency over a full season.
• COP of 2.41 at -8 °C and 2.10 at -15 °C: heat delivered per unit of electricity, while an electric baseboard delivers one for one.

These figures come from certificate AHRI 215324157, published by NEEP.

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, step by step

Visit, location and outdoor unit

The visit is free. We measure the room, look at the windows, the orientation and the floor level, then run a load calculation. The wall head is secured to the framing, up high, on a wall from which air covers the living space, with a drainage slope for condensate. In a plex, the outdoor unit goes, depending on the case, on a ground stand in the yard, on a wall stand, on a back balcony or on the roof, always above the snow line and away from bedroom windows, including the neighbours'.

Lines, electrical and commissioning

The refrigerant lines, the communication cable and the drain go through a single sealed opening, and a line cover can finish the run along the rear facade. The system needs a dedicated circuit at the apartment's panel: we check its capacity during the visit, because panels in older plexes are often already well filled. At commissioning, the circuit is evacuated and checked for tightness, then we test cooling, heating and the drain, and set the baseboards as backup.

Maintenance

Rinse the indoor filters every two weeks in season, keep the outdoor unit clear of snow and leaves, and plan annual HVAC maintenance of the coils, drain and electrical connections. In winter, white vapour during defrost and a short pause in heating are normal. Our cleaning service takes over when you prefer to hand off the annual visit, a practical option for owners of several units.

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 Wall-Mounted Heat Pump ARCOAIRE 16.8 SEER | 18,000 BTU - R454B. We visit the apartment, confirm the right size and give you a written quote before signing.