3-Zone Heat Pump CONFORTO MHMZ | 48,000 BTU - R410A
The Conforto MHMZ 48 000 multi-zone heat pump heats and cools 3 rooms with a single outdoor unit. ENERGY STAR cold-climate certified, it delivers 36,000 BTU/h at −8 °C, heats down to −30 °C and qualifies for a $4,320 LogisVert grant. Installed by AirGreen in Montréal, Laval, Longueuil, the North Shore and the South Shore.
3 rooms, one outdoor unit.
Figures come from the manufacturer’s data and the AHRI certification.
The parts that make a multi-zone system.
Tap a part to learn more.
Outdoor unit
One compressor for the whole house. It supplies up to 5 heads.
Base pan heater
A heater keeps the outdoor unit’s base pan free of ice below 1 °C and during defrost (NEEP).
Refrigerant lines
One pair of lines per head.
Indoor heads
One head per room, each with its own remote and temperature. The combination is chosen in the “Zones” menu.
Control
Each zone is set separately.
Turn rooms on and off. Watch the power being shared.
One outdoor unit supplies every head: when several rooms call at once, they share its capacity. Pick an outdoor temperature.
Tell us your rooms. We tell you if this size is enough.
Pick the number of rooms and their size. The estimate targets a −15 °C day; it is a guide, the real calculation is done room by room at your home.
The whole series at a glance: find the box that fits you.
Each box is a product: the outdoor unit’s size, and the number of heads.
At −15 °C, it still delivers 93 % of its rated capacity.
Tap a temperature: capacity, efficiency and the cost of one hour of heating.
At every temperature, cheaper than baseboards.
Cost of one hour at full output, for the same heat delivered. Hydro-Québec Rate D, second tier: 11.142 ¢/kWh.
The official ratings, on the same scales as before.
SEER2, HSPF2 and EER2 come from the AHRI certification.
A grant you can calculate, not guess.
The capacity at −8 °C. $120 per 1,000 BTU/h is the rate for ENERGY STAR cold-climate heat pumps (guide v1.10).
One multi-zone or several wall units? Both sides, honestly.
We compare both options on your floor plan during the estimate.
What to know before installing a multi-zone system.
Dimensions, wiring and lines, drawn. Then our six steps.
The outdoor unit, dimensioned
One circuit for the whole house
Published sound levels, on one scale.
We use the outdoor figure to choose where the unit goes.
What is particular about this machine.
Only facts published by ENERGY STAR, NEEP or the manufacturer.
Every number, and where it comes from.
Each line carries its source; a line with no published value is not shown.
The manufacturer’s documentation, as PDF.
Everything we have written about this system.
A cathedral-ceiling living room and two bedrooms, served by the same condenser
A living room with a cathedral ceiling is often the most beautiful room in the house and the hardest to keep comfortable. Heat rises to the ridge in winter, large windows let the sun in during summer, and the bedrooms, closed and lower, live in a completely different climate. The 3-Zone Heat Pump CONFORTO MHMZ | 48,000 BTU - R410A treats these three spaces separately, with three wall heads connected to a single MHMZ548DACFC condenser.
This 4-ton condenser serves 3 zones here and accepts up to 5 at most. The wall heads intended for it are the MHWAL09DACFC, the MHWAL12DACFC and the MHWAL24DACFC. Its certified ratings are 21.8 SEER2, 11.7 EER2 and 9.8 HSPF2. The system is ENERGY STAR certified with the cold-climate designation under ENERGY STAR ID 2495078, and it qualifies for a $4,320 LogisVert grant.
The challenge of a high ceiling
In a tall room, air settles in layers. Warm air collects under the ceiling, cool air stays at floor level, and your feet can be cold in a room that seems warm on the thermometer. The large glazed areas common in these living rooms add losses in winter and heat gains in summer. A small wall head is not enough to stir such a volume.
This size therefore targets homes whose main room is large and tall: a bungalow with a cathedral ceiling, a country house with a mezzanine, a living room extended under a sloped roof. The other two zones serve the bedrooms. The load calculation accounts for the room's actual volume, not just its floor area.
The MHWAL24DACFC in a large volume
For the living room, we plan the MHWAL24DACFC, the largest of the intended heads. It is not installed at the top of the wall, where the air is already warm, but at a height that lets it blow toward the occupied zone and remains accessible for filter maintenance. It blows along the length of the room, toward the windows rather than against a wall.
A ceiling fan helps a great deal in these rooms. Set to push air gently downward in winter, it brings the heat collected under the ridge back to the occupied zone and makes the head's work more effective. If your living room already has one, we take it into account when choosing the location.
The two bedrooms
The bedrooms get smaller heads: the MHWAL12DACFC for the main bedroom, the MHWAL09DACFC for a child's or guest room. Closed at night, they need their own set point, independent of the living room's.
The three heads share the condenser's capacity. During the day, the living room takes the largest share; at night, the bedrooms do. With 3 zones out of a maximum of 5, two connections remain free to equip another bedroom or an office later, after checking the remaining capacity.
A mezzanine open to the living room is a special case. It benefits from the large room's air in winter, but it collects heat under the roof in summer and quickly becomes the hottest zone in the house. During the visit, we assess whether the living-room head is enough to cover it or whether it deserves its own head on one of the free connections.
Winter according to the certificate
The certificate lists 36,000 BTU/h at -8 °C (17 °F), with a COP of 2.30, and 45,000 BTU/h at -15 °C (5 °F), with a COP of 2.00. The maximum published capacity is 45,000 BTU/h at -15 °C. The two points are measured separately; we report each one as published.
A COP of 2.00 means that at -15 °C, each kilowatt-hour consumed returns two kilowatt-hours of heat, where an electric baseboard returns one. At -8 °C, the ratio rises to 2.30. ENERGY STAR's cold-climate designation confirms that the combination meets the low-temperature performance criteria.
These figures come from certificate AHRI 210605819, published by NEEP.
Backup heat and defrost
The certificate does not publish a point colder than -15 °C. In a heavily glazed living room, backup remains worthwhile: the existing electric baseboards or fireplace stay in place, set slightly below the heads' set point, and take over during extreme cold. In cold, humid weather, the condenser also runs defrost cycles of a few minutes; the heads then stop blowing warm air and a cloud of vapour rises from the outdoor unit. This is normal.
The inverter compressor and its three zones
The inverter compressor varies its speed according to demand and meters the R-410A refrigerant sent to each head. In the living room, it runs for long periods at moderate speed, which keeps the air moving continuously and limits stratification. Shutting off an unoccupied bedroom leaves the other two zones running normally. As on any multi-zone system of this type, the three heads work in the same mode, heating or cooling.
Summer under a cathedral ceiling
In cooling, the system is built around a nominal size of 48,000 BTU/h for the three zones. In a tall, glassy living room, sunny afternoons are what count: blinds on the upper windows lighten the load considerably. Extended low-speed operation removes moisture from the air, and each head offers a dehumidification mode for muggy days. The bedrooms, for their part, are cooled for the night without cooling the whole living room.
The 21.8 SEER2, 11.7 EER2 and 9.8 HSPF2 ratings
The HSPF2 of 9.8 measures heating efficiency over the whole cold season; in Quebec, it is the rating that weighs most on the bill. The SEER2 of 21.8 measures cooling efficiency over a whole summer, and the EER2 of 11.7 measures cooling at full load, in hot weather. The COP expresses efficiency at a specific temperature: it is the ratio between heat delivered and electricity consumed.
The $4,320 LogisVert grant
The system is listed in Hydro-Québec's LogisVert program, with $4,320 for the owner of an existing home, according to the list in effect on the installation date. We confirm eligibility before signing and prepare the detailed invoice, model numbers and proof of payment. Our page on the efficient heat pump grant summarizes the program's conditions.
Installation and maintenance
Our installation
After the visit and the load calculation, the condenser is installed above the snow line, on a stand or a sturdy bracket, away from snow sliding off the roof. A 4-ton condenser requires a larger dedicated circuit than a small wall-mounted heat pump; we check the panel's space and capacity during the visit.
Each head gets its own refrigerant line set back to the condenser, grouped in a line cover outdoors, and its own sloped condensate drain. Commissioning includes the vacuum, the leak test, a check of each zone and setup of the three remotes with you.
Maintenance
Rinse the filters of all three heads every two weeks in season; the living-room one comes out with a stepladder, hence the importance of its location. Keep the condenser clear of snow and leaves, without covering it in winter. One HVAC maintenance visit per year cleans the coils, fans and drains and checks the electrical connections. Our cleaning service takes over when you prefer to hand off the annual visit.
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 3-Zone Heat Pump CONFORTO MHMZ | 48,000 BTU - R410A. We assess your living room and bedrooms and confirm the right size and your grant eligibility before signing.
What people ask us about multi-zone systems.
Can I heat one room and cool another at the same time?
No. On a multi-zone system like this one, every head works in the same mode, heating or cooling. Each room still keeps its own set temperature.
What happens when every room calls for heat?
They share the outdoor unit’s capacity: 36,000 BTU/h at −8 °C, 45,000 at −15 °C.
How many heads can I connect?
Up to 5 on this outdoor unit. This product is configured for 3 heads.
How much is the LogisVert grant?
$4,320. The grant never exceeds 100 % of the cost before taxes; apply within 9 months of installation.
Is it ENERGY STAR certified?
Yes, cold climate, ID 2495078.
Down to what temperature does it heat?
Down to −30 °C.
Is it noisy?
Outdoors, 65 dB(A): we place the unit away from bedroom windows.
Why a multi-zone instead of several wall units?
One outdoor unit on the wall and one circuit. In return, the rooms share the capacity, and if the outdoor unit stops, every zone stops.
A multi-zone system is planned room by room. At your home.
We measure every room, draw the line route and choose the right head for each zone. The on-site estimate is free and the quote arrives within 24 h.