LG Multi F MAX LGRED R32 Heat Pump | 5 Zones + 42000 BTU | Montérégie
The LG Multi F Max LGRED R32 42 000 multi-zone heat pump heats and cools 5 rooms with a single outdoor unit. it delivers 31,600 BTU/h at −8 °C, heats down to −25 °C and qualifies for a $3,792 LogisVert grant. Installed by AirGreen in Montréal, Laval, Longueuil, the North Shore and the South Shore.
5 rooms, one outdoor unit.
Compared with the 86 multi-zone systems of 42,000 BTU we sell. Every number on this page carries its source.
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 6 heads and modulates from 12,420 to 53,200 BTU/h depending on what the rooms call for (NEEP).
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, also from your phone.
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 104 % of its rated capacity.
Tap a temperature: certified capacity, efficiency and the cost of one hour of heating.
It slows down, it speeds up: the certified modulation range
Light bar: from minimum to maximum capacity. Dark mark: the rated value.
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. The mark shows the median of the same-size multi-zone systems we sell.
A grant you can calculate, not guess.
The capacity at −8 °C comes from Hydro-Québec’s list of October 1, 2026. $120 per 1,000 BTU/h is the rate for ENERGY STAR cold-climate heat pumps (guide v1.10).
Where it ranks among same-size multi-zone systems.
Compared with the 86 multi-zone systems of 42,000 BTU we sell, using the LogisVert list figures. Weaknesses too, said plainly.
Against three other brands in its class.
Same rated size, other manufacturers. Pick the opponent.
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 multi-zone HVAC solution designed for complex buildings in Montérégie
In many residential and multi-unit projects in the Montérégie region , a single-zone heat pump quickly reaches its limits. Multi-storey houses, duplexes, large condos, renovations with architectural constraints: these configurations require a truly flexible, stable, and efficient multi-zone HVAC solution for cold climates.
It is precisely in this context that the LG Multi F MAX LGRED R32 Heat Pump – 5 zones, 42,000 BTU stands out as a serious technical reference, when it is correctly sized and installed by a specialized team like AirGreen .
At AirGreen , we install this type of system in projects where precision, thermal load management, and long-term reliability are non-negotiable. This LG model isn't for everyone: it's designed for buildings that require intelligent heating and cooling distribution without the need for multiple outdoor units.
Understanding the Multi F MAX logic: an HVAC architecture designed to last
The LG Multi F MAX LGRED R32 series is based on an advanced architecture: a single outdoor unit powers up to 5 indoor units (with the technical possibility of up to 6 zones depending on the configuration). Each zone operates independently, both in terms of temperature and airflow, allowing for precise room-by-room comfort management .
In practice, this means:
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A north-facing room can be heated without unnecessary overconsumption elsewhere
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A south-facing glazed area can be independently air-conditioned.
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Short cycles, which cause premature wear, are avoided.
This flexibility is essential in the plexes of Longueuil , the intergenerational homes of Boucherville , or the renovated residences of Saint-Jean-sur-Richelieu , where thermal needs vary greatly from one area to another.
Actual capacity and behavior in cold climates
Unlike many systems that are oversized on paper but unstable in real-world conditions, the LG Multi F MAX KUMXA421A offers consistent and measurable capability:
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Nominal cooling capacity: 42,000 BTU
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Reliable operation down to -25°C in heating mode
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Output at -8°C: approximately 31,600 BTU
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Output at -15°C: approximately 44,000 BTU
These values must always be interpreted correctly according to the actual configuration of the refrigeration network.
At AirGreen, we always emphasize one point: performance depends as much on the installation as on the machine itself . A poorly balanced Multi F MAX quickly loses its advantages.
The technical choices that make the difference on the field
R-32 refrigerant: efficiency and compliance
The R-32 gas used in this model has a lower global warming potential than previous generations. But beyond the environmental aspect, it also allows for:
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Improved heat transfer
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A reduced refrigeration load
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Increased stability at low temperatures
This translates into better real energy efficiency , particularly noticeable in the winters of Montreal , Laval and the South Shore .
Electrical and acoustic data to consider
Electrically, the outdoor unit operates on 220V , with:
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MCA: 33 A
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MOP: 40 A
These values necessitate a thorough analysis of the electrical panel , a step systematically carried out by AirGreen before any installation.
In terms of noise, the external sound level of approximately 56 dB(A) remains very controlled for a unit of this capacity, which is essential in dense or regulated residential environments.
Real-life installation scenarios created by AirGreen
Case 1: Renovated duplex in Longueuil
Project with two superimposed dwellings, load-bearing walls retained, impossibility of installing two outdoor units.
Solution :
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1 LG Multi F MAX LGRED R32 outdoor unit
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5 wall-mounted indoor units of varying capacities
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Optimized distribution via branch units
Result :
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Major reduction in external footprint
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Independent comfort for each accommodation
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Stable energy consumption during periods of extreme cold
Case 2: Intergenerational home in Montérégie
Separate zones are needed for the floors and the annex accommodation.
Common problem: temperature conflicts and noise complaints with improperly sized systems.
Thanks to a detailed analysis of thermal loads , AirGreen configured the Multi F MAX to avoid any overallocation of capacity, ensuring constant thermal stability .
What to avoid with a multi-zone system
We regularly see the same errors in installations carried out without specific expertise:
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Pipe lengths not respected
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Poor zone balancing
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Lack of precise calculation of heat losses
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Poor selection of indoor units
With such a sophisticated system, these errors quickly negate the expected benefits. At AirGreen, every Multi F MAX project is treated as a custom project , never as a standard installation.
Why entrust your LG Multi F MAX project to AirGreen
Choosing AirGreen is not simply buying a heat pump:
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Over 15 years of HVAC experience in Greater Montreal
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Team of refrigeration technicians specializing in multi-zone systems
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Complete mastery of electrical and refrigeration standards
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Complete transparency regarding actual performance and technical limitations
We regularly work with residential, multi-unit residential and light commercial projects requiring a rigorous approach.
A solution eligible for provincial subsidies
This model is eligible for the LogisVert grant , with an amount of up to $3,792 depending on the configuration and criteria in effect at the time of installation. AirGreen will assist you with the eligibility analysis and application preparation.
Conclusion: A demanding, but remarkably efficient, multi-zone heat pump
The LG Multi F MAX LGRED R32 5-zone, 42,000 BTU heat pump is a high-performance solution. It doesn't tolerate improvisation, but when properly designed, installed, and balanced , it delivers outstanding comfort, consistent efficiency, and seamless integration into complex projects.
Take action with AirGreen
Are you planning a project in Montreal , Laval , Longueuil , the South Shore or the North Shore ?
Contact AirGreen now for a complete analysis, a detailed quote and an HVAC installation that meets the highest market standards .
Warranty: 10 years on the compressor, 10 years on parts and 6 years on labor, straight from the distributor.
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: 31,600 BTU/h at −8 °C, 44,000 at −15 °C.
How many heads can I connect?
Up to 6 on this outdoor unit. This product is configured for 5 heads.
How much is the LogisVert grant?
$3,792 according to Hydro-Québec’s list of October 1, 2026. 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 3621281. It also meets the ENERGY STAR Most Efficient criteria, according to the ENERGY STAR database.
Down to what temperature does it heat?
Down to −25 °C.
Is it noisy?
Indoors, the reference head goes down to 29 dB(A). Outdoors, 56 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.
What does the warranty cover?
Our sheet lists 10 years on the compressor and 10 years on parts. AirGreen extended warranty: possible.
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.