People sleep cool and sit warm. A house on one thermostat has to pick a side, so somebody is under a blanket on the sofa or somebody is awake at 3 am with the window open.

The pairing here does the picking for you: two 9,000 BTU ducted air handlers for the bedrooms and two 12,000 BTU units for the living space, four wall thermostats in total. Only the zones that are switched on draw from the 35,000 BTU outdoor unit.

Four zones, nothing on the wall

Every room in the drawing has a slim grille in the ceiling instead of a box on the wall. That is the reason people choose concealed ducted over wall heads: in a room with tall windows, picture walls or a heritage cornice, there is nowhere good to put a wall unit. The grille and a short duct run solve it.

What is actually in the cartons

Four of every per zone item: a copper gas pipe and liquid pipe at 16 ft, a communication wire at 19 ft, a drain hose, a wall thermostat, a remote, a wall sleeve, mounting foot pads and a screw kit. Ducting, grilles and the flexible duct itself are not included and are sized by your installer for each room.

Wall thermostat, remote, phone or voice

A hidden air handler needs a control you can see, and each zone gets a wired wall thermostat for that. The remote, the app and voice through Alexa or Google Home all work as well. Four thermostats on four walls is the closest this gets to a conventional ducted system, except each one only commands its own zone.

Seven modes behind the grille

The panel lists seven modes including ECO and sleep, and eight fan speeds starting at mute. 4D auto swing works the grille vanes so air spreads across the room rather than dropping in one column. A self clean cycle dries the coil after a cooling run, which matters more when the unit is out of sight.

One 35,000 BTU outdoor unit runs all four ducted air handlers. Each zone starts, stops and holds its own temperature, so an empty room costs nothing to leave alone.

A common rule of thumb is 20 to 25 BTU per square foot (Carrier publishes 25). On that basis a 9,000 BTU unit suits roughly 360 to 450 sq ft and a 12,000 BTU unit suits roughly 480 to 600 sq ft. Natural Resources Canada points to CSA F280-12 for a proper load calculation.

The compressor varies its speed instead of cycling on and off. Published ratings are 22.5 SEER2 for cooling and 10 HSPF2 for heating on R454B refrigerant.

A chassis electrical heater keeps the outdoor base pan clear. The manufacturer rates heating down to -25°C (-13°F) and cooling up to 55°C (131°F).

Each zone gets a 16 ft insulated copper line set and 19 ft of communication wire, plus a drain hose. That is the material most quotes list separately, four times over on a system this size.

The outdoor unit runs on 208-230V 60Hz. This is not a standard 15 amp household outlet. It wants its own branch circuit, sized from the MCA and maximum breaker figures on the unit's own nameplate, with a disconnect within reach.

Four wired wall thermostats, four remotes, the phone app and voice control through Alexa or Google Home. A 24 hour timer and a child lock are built in.

A self clean cycle dries the coil after cooling, and the filter washes out. Both matter more on a hidden air handler, because nobody walks past it and notices.

Ships from our United States warehouse. Delivery to Canada usually takes 8 to 14 business days, with no customs charges or duties to pay on arrival. Free shipping on orders over $150, a flat $18.90 below that, and tracking by email as soon as it leaves.

Return within 14 days of purchase, unused, in original condition and packaging.

Covered directly by the manufacturer under their warranty terms for material and manufacturing defects.

Found it cheaper at a Canadian retailer? Send us the link and we will match that price. It has to be the same item, in stock, sold and shipped inside Canada, and compared like for like on what comes in the box.

Two zones at 9,000 BTU for bedrooms, roughly 360 to 450 sq ft each, and two at 12,000 BTU for living space, roughly 480 to 600 sq ft each.

Glass walls, a cornice worth keeping, a bed under the only free wall. A concealed air handler above the ceiling leaves a slim grille and nothing else on show.

This is a heat pump, not a cooling only air conditioner. It carries a 10 HSPF2 heating rating and a chassis electrical heater on the outdoor unit for cold weather.

What we stand behind

• Ships from our United States warehouse, free shipping over $150, and 14 day returns unused in the original packaging.
• 14 day returns on unused items in original condition and packaging
• Covered by the manufacturer's own warranty for material and manufacturing defects
• Line sets, communication wire and a controller for every one of the four zones are in the box

How much space will each ducted air handler cover?

Sizing runs off the heat load of the room, not just its floor area, and Natural Resources Canada points to CSA F280-12 for the real calculation. As a rough check, 20 to 25 BTU per square foot is the usual rule of thumb. On that basis a 9,000 BTU unit suits roughly 360 to 450 sq ft and a 12,000 BTU unit suits roughly 480 to 600 sq ft. Poor insulation, large west facing windows or a 9 ft ceiling all push the figure up.

The four ducted air handlers add up to 42,000 BTU but the outdoor unit is 35,000 BTU. Is that a mistake?

No. On any multi zone system the indoor ratings are not meant to be added together, and multi zone sizing guides say so plainly. The 35,000 BTU figure is what the outdoor unit can deliver at one time, shared among whichever zones are calling for it. Four rooms rarely peak at the same moment, which is why this combination is offered.

How cold can it get outside before it stops heating?

The manufacturer rates low ambient heating down to -25°C (-13°F), helped by an electric heater in the outdoor chassis. Natural Resources Canada notes that air source heat pumps lose capacity and efficiency as it gets colder, with typical COPs falling from 2.0 to 5.4 at 8°C to 1.1 to 3.7 at -8°C, and that most newer units have a minimum operating temperature between -15°C and -25°C. Keep a backup heat source for the coldest stretches.

Can I install this myself in Canada, and does it run on a normal outlet?

No on both counts. The outdoor unit runs on 208-230V 60Hz, so it needs its own branch circuit and an electrician, not a wall socket. Refrigerant work is also regulated: Ontario, for example, states that only a certified technician may remove, discharge, handle and dispose of refrigerants including HFCs, and that mechanical work on refrigeration equipment needs a Certificate of Qualification on top of that. Other provinces have their own halocarbon rules, and the federal Code of Practice says the same thing in plainer terms.