LG MULTI F MAX R32 5-Zone Heat Pump | 54,000 BTU Compressor
The LG Multi F Max R32 54 000 multi-zone heat pump heats and cools 5 rooms with a single outdoor unit. it delivers 37,200 BTU/h at −8 °C, heats down to −16 °C and qualifies for a $1,860 LogisVert grant. Installed by AirGreen in Montréal, Laval, Longueuil, the North Shore and the South Shore.
5 rooms, one outdoor unit, and the most powerful in its class at −8 °C.
Compared with the 7 multi-zone systems of 54,000 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 8 heads and modulates from 12,420 to 48,000 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 72 % 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. $50 per 1,000 BTU/h is the rate for ENERGY STAR heat pumps (guide v1.10).
Where it ranks among same-size multi-zone systems.
Compared with the 7 multi-zone systems of 54,000 BTU we sell, using the LogisVert list figures. Weaknesses too, said plainly.
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 demanding buildings in Quebec
At AirGreen , we have been installing multi-zone systems for many years in real-world settings: single-family homes, duplexes, triplexes, multi-unit buildings, and complex commercial spaces in Montreal , Laval , Longueuil , and on the North and South Shores . The LG MULTI F MAX R32 5-Zone Heat Pump – 54,000 BTU fits perfectly into this reality: a centralized solution capable of supplying several independent zones while maintaining high energy efficiency, even in Quebec winter conditions.
This model is aimed at owners and managers who wish to replace several stand-alone systems with a single robust outdoor unit, reduce clutter, improve room-by-room control and optimize overall building energy consumption.
Understanding multi-zone logic: why this system is a game changer
One outdoor unit, up to 8 indoor zones
The heart of the system is the LG KUMXB541A outdoor unit, capable of powering up to 5 active zones (and a maximum of 8 zones depending on the configuration) . Each indoor zone operates independently: temperature, heating or cooling mode, airflow, and programming.
In practice, this allows, for example:
-
to heat a frequently used living room,
-
to maintain rooms at a more moderate temperature,
-
to air-condition a home office without overloading the entire system.
At AirGreen, we have installed this type of configuration in several residences in Laval-des-Rapides and Boucherville , where clients wanted to replace energy-intensive electrical systems without opening up walls to install central conduits.
Intelligent capacity management
With a nominal capacity of 54,000 BTU , the system automatically redistributes capacity according to the actual demand of the indoor units. This prevents excessive on/off cycles, reduces wear on components, and improves overall thermal comfort.
Technical performance adapted to the Quebec climate
Reliable heating in cold weather (data measured under standardized conditions)
The LG MULTI F MAX R32 heat pump is designed to maintain stable operation in winter. The following values correspond to the maximum heating capacities at standard outdoor temperatures:
-
48,000 BTU/h at 17 °F (≈ -8.3 °C)
-
40,500 BTU/h at 5 °F (≈ -15 °C)
-
35,200 BTU/h at -4 °F (≈ -20 °C)
In practice, this type of behavior is particularly relevant on the North Shore (for example in Blainville and Mascouche ) and in some windier areas of the South Shore , where low-temperature heating performance becomes a decisive criterion for multi-story buildings with unequal loads.
Efficiency indicators (COP measurements instead of oversized seasonal values)
For a multi-zone system of this category, the most reliable efficiency benchmarks to compare between models and projects are the COPs measured under test conditions:
-
COP in air conditioning (outside 95 °F / ≈ 35 °C): 3.69
-
COP in heating mode (outside 47 °F / ≈ 8.3 °C): 3.35
These figures describe actual energy efficiency under standardized conditions. In our projects, the impact on the bill then depends on the sizing, the number of simultaneously active zones, occupancy, instructions, and the quality of the installation.
R-32 refrigerant: a technical and environmental choice
Why R-32 makes a difference
R-32 gas has a lower global warming potential than older refrigerants. In addition to its reduced environmental impact, it offers:
-
improved thermal efficiency
-
a lower refrigerant charge,
-
a faster response to load variations.
In our commercial projects in Montreal East , this choice is often motivated by internal policies to reduce carbon footprint and by compliance with current and future standards.
Installation flexibility: a major advantage in renovation
Generous pipe lengths and elevation changes
This system accepts:
-
a total piping length of up to 475.7 ft ,
-
a maximum elevation difference of 98.4 ft between the outdoor unit and the indoor units .
In practical terms, this allows us to install the outdoor unit on a roof, backyard or wall mount, while serving homes spread over several floors, without compromising performance.
Compatible with several types of indoor units
The LG MULTI F MAX is compatible with a wide range of LG wall units:
KNUAK091A, KNUAK121A, NUAK181A, KNMAB071A, KNUAB091A, KNUAB121A, KNMAB151A, KNUAB181A, KNMAB241A .
At AirGreen, we often combine different capacities (9,000, 12,000, 18,000 BTU) in the same project in order to precisely adapt each zone to its actual thermal load.
Noise level and acoustic comfort
Discretion both indoors and outdoors
-
Indoor units : from 29 dB(A) depending on the model chosen
-
Outdoor unit : 55 dB(A)
In a project completed in Outremont , the client was concerned about noise due to rooms located near the outdoor unit. Careful site planning and the use of vibration-damping mounts resulted in virtually imperceptible operation, even during intensive heating.
Electricity, safety and compliance
Key electrical data
-
Voltage: 208–230 V (single phase)
-
MCA: 33.3 A
-
MOP: 40 A
These parameters are essential to ensure a compliant and safe installation. At AirGreen, we systematically coordinate with master electricians to avoid any overload or non-compliance with the Quebec Electrical Code.
LogisVert subsidy: a concrete financial advantage
At the time of writing, this system is eligible for a $1,860 LogisVert provincial grant . For many of our clients in Longueuil and on the South Shore , this financial assistance tipped the scales towards a more efficient multi-zone system rather than a minimalist solution.
What we learned on the ground
Common mistakes to avoid
-
Undersizing certain areas for the sake of initial cost savings
-
Neglecting pipe routing planning
-
Choosing a multi-zone system without considering the actual habits of the occupants
We have seen projects where poor power distribution led to persistent discomfort. At AirGreen, every installation begins with a detailed analysis of the loads and actual usage.
Observed results
-
More stable thermal comfort
-
Decrease in complaints related to temperature variations
-
Better control of electricity bills over 12 months
Why entrust the installation to AirGreen
-
Certified and experienced refrigeration technicians
-
$5M liability insurance
-
Transparent pricing, no surprises
-
Recognized expertise in complex multi-zone systems
We don't just install a device: we design a sustainable HVAC solution, tailored to your building and your long-term goals.
Conclusion
The LG MULTI F MAX R32 5-Zone Heat Pump – 54,000 BTU represents a high-performance HVAC solution for residential and commercial buildings that demand flexibility, energy efficiency, and reliability in cold climates. Properly designed and installed, it transforms thermal comfort management while reducing operating costs.
Contact AirGreen today for a personalized assessment, a detailed quote, or to discuss your project in Montreal , Laval , Longueuil , on the North Shore or South Shore . Our team will support you every step of the way, from analysis to installation.
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: 37,200 BTU/h at −8 °C, 39,000 at −15 °C.
How many heads can I connect?
Up to 8 on this outdoor unit. This product is configured for 5 heads.
How much is the LogisVert grant?
$1,860 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, ID 3621275. It also meets the ENERGY STAR Most Efficient criteria, according to the ENERGY STAR database.
Down to what temperature does it heat?
Down to −16 °C.
Is it noisy?
Indoors, the reference head goes down to 29 dB(A). Outdoors, 55 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.