LG

LG MULTI F MAX R32 3-Zone Heat Pump | 54,000 BTU Compressor

In stock
SKU: KUMXB541A-3
Provincial Subsidy (LogisVert): 1860 $ (Updated: November 26, 2025)
Model Number (External): KUMXB541A
AHRI: 215402341
ENERGY STAR®: Yes
ENERGY STAR® (Cold Climate): No / No
# ENERGY STAR ID: 3621275
Heating Capacity: -16 °C
Cooling Capacity: 54,000 BTU
Gas (Freon): R-32
WiFi: Included

SEER2 (Seasonal Air Conditioning Efficiency)

1 20.6 30

HSPF2 (Seasonal heating efficiency)

1 9.5 15

EER2 (Instantaneous efficiency in air conditioning)

1 12.6 20

COP at -8 °C (Heating energy efficiency)

1 2.19 3
Nominal Power: 54,000 BTU
Power at -8°C: 37200 BTU
Power at -15°C: 39000 BTU
Interior Dimensions (L x D x H): 32.94 x 7.56 x 12.13 in ***
Vertical flap control (Air direction): Auto ***
Horizontal flap control (Air direction): Auto ***
Sound Pressure Level (Indoor): 29 / 38 dB(A) ***(depending on the model chosen)***
Possible Model Number (Interior): KNUAK091A, KNUAK121A, NUAK181A, KNMAB071A, KNUAB091A, KNUAB121A, KNMAB151A, KNUAB181A, and KNMAB241A

CFM (Airflow) (12,000 BTU***)

1 459 700
External Dimensions (L x W x H): 37.41 x 15.66 x 54.34 in
Zones: 3 Zone (Triple Zone)
Maximum Zones: 8 Areas
Sound Pressure Level (Exterior): 55.0 dB(A)
Voltage: 220 V
MCA (Minimum Circuit Ampacity): 34 A
MOP (Maximum Overcurrent Protection): 40 A
Warranty (Compressor - Parts - Labor): 10-10-0 years
Additional Warranty: Possible

A multi-zone HVAC solution designed for demanding buildings in Greater Montreal

In numerous residential and multi-unit projects in Montreal , Laval , Longueuil , and on the North and South Shores, we observe the same reality: efficiently heating and cooling multiple spaces with a single system quickly becomes complex if the equipment isn't perfectly suited. The LG MULTI F MAX R32 3-Zone Heat Pump | 54,000 BTU Compressor addresses this very issue. At AirGreen , we install it when performance, flexibility, and reliability must coexist without compromise.

This multi-zone system is designed to power up to three active zones , with the option to expand to more zones depending on the configuration. It is suitable for owners of large houses as well as apartment buildings, offices, or commercial spaces where each zone needs to be controlled independently, without requiring multiple outdoor units.


A multi-zone architecture designed for true flexibility

Independent management of areas

The LG MULTI F MAX 's greatest strength lies in its ability to power multiple indoor units of varying capacities from a single outdoor compressor. In practice, this means:

  • A bedroom that can be maintained at a stable, quiet, and moderate temperature

  • An open-plan living room with superior heating or air conditioning capacity

  • A separate office, shop or dwelling regulated independently

Each zone operates according to its own needs, without unnecessarily straining the entire system.

Extended compatibility of indoor units

We particularly appreciate this model's broad compatibility with various types of LG indoor units: wall-mounted, console, ceiling-mounted, or ducted. During installations in Laval and Longueuil , this flexibility allowed us to integrate the system into existing buildings without altering the interior architecture—a significant advantage for renovations.


Thermal performance adapted to the Quebec climate

Stable and useful heating when it's cold

Quebec's climate imposes high heating requirements. With this type of multi-zone system, what matters is not just the BTU "size," but the ability to deliver actual heat when the temperature drops.

For this outdoor unit, the published capacities show a significant reserve in winter:

  • Heating capacity (min. – nominal – max.): 12,420 – 58,000 – 64,000 BTU/h

  • Maximum heating at 17°F (≈ -8°C): 48,000 BTU/h

  • Maximum heating at 5°F (≈ -15°C): 40,500 BTU/h

  • Maximum heating at -4°F (≈ -20°C): 35,200 BTU/h

On the ground, these figures become concrete in projects on the North Shore where the system must maintain a stable level of comfort, even when areas demand it simultaneously.

Strong and stable air conditioning during heatwaves

In summer, the air conditioning capacity is sized for high loads (flat roofs, large windows, upper floors, very sunny dwellings):

  • Cooling capacity (min. – nominal – max.): 10,800 – 50,500 – 63,200 BTU/h

This is precisely the kind of profile we often encounter in Montreal and Longueuil , where sunlight exposure varies enormously from room to room.

Energy efficiency: the right indicators, in the right place

To avoid any confusion: SEER2 / HSPF2 values ​​often depend on the exact match (combinations of indoor units, ratios, configurations) and may be displayed inconsistently if incorrectly imported into a product page.

Here, the simple and consistent indicators to remember are the COPs under nominal conditions:

  • COP in air conditioning (at 95°F): 3.69

  • COP in heating mode (at 47°F): 3.35

In plain terms: under nominal conditions, each kW of electricity consumed is converted into several kW of useful thermal capacity, which explains why this type of multi-zone heat pump is popular in Greater Montreal when it is well designed and well installed .


R-32 refrigerant: efficiency and environmental responsibility

The LG MULTI F MAX uses R-32 gas , known for its lower global warming potential compared to older refrigerants. In our recent HVAC projects in Montreal and the Montérégie region, this choice is increasingly important for clients sensitive to environmental issues and future regulations.

R-32 also allows:

  • Improved thermal efficiency

  • A reduced refrigerant charge

  • Simpler and safer maintenance


Essential technical data for a reliable installation

At AirGreen , we always emphasize the importance of respecting electrical and mechanical parameters to ensure the longevity of the system:

  • Voltage : 208–230 V (single phase)

  • MCA (minimum circuit ampacity) : 33.3 A

  • MOP (maximum protection) : 40 A

  • Operating range :

    • Cooling: 14°F to 118°F

    • Heating: -4°F to 64°F

  • Noise level (outdoor, sound pressure) : 53 dB(A) in air conditioning / 55 dB(A) in heating

  • Refrigerant charge : 7.5 lb

These characteristics facilitate integration into dense residential areas, particularly in Montreal , where noise constraints are a real issue.

The extensive piping capacities and permissible height differences offer great flexibility in layout, which is particularly advantageous in multi-story buildings or complex configurations.


LogisVert subsidy: a concrete financial lever

At the time of writing, this model is eligible for a $1,860 LogisVert provincial grant . We systematically assist our clients in Laval , Longueuil , the South Shore , and the North Shore in validating eligibility and preparing the required documents, so that the grant is actually obtained, and not simply mentioned on a quote.


Real-life installation scenarios at AirGreen

Intergenerational housing in Laval

In an intergenerational residence, we installed this system to serve:

  • The main residence

  • A secondary dwelling in the basement

  • A separate office space

Multi-zone control allowed each occupant to adjust their temperature without conflict, while maintaining a single, discreet outdoor unit.

Apartment building on the South Shore

In a triplex apartment, the LG MULTI F MAX replaced three separate systems. The result:

  • Reduction of external footprint

  • Centralized maintenance

  • Better distributed energy consumption

The owners quickly noticed a decrease in operating costs.


Common mistakes that we systematically avoid

Our field experience has taught us that the performance of a multi-zone heat pump depends as much on the installation as on the equipment itself. In particular, we avoid:

  • Oversizing the compressor

  • Poor distribution of power across areas

  • Suboptimal pipe lengths

  • Inadequate electrical protection

Each project begins with a thermal analysis and rigorous planning, adapted to the actual building, and not to a theoretical scenario.


Why entrust this project to AirGreen?

Choosing AirGreen means benefiting from:

  • Certified refrigeration technicians specializing in multi-zone systems

  • $5 million in liability insurance

  • Transparent pricing , confirmed before work begins

  • A structured and accessible after-sales service

We never propose this type of system unless we are convinced that it truly meets the client's needs.


A heat pump designed to last

With a 10-year warranty on the compressor and parts , and the possibility of an additional warranty, the LG MULTI F MAX R32 3-Zone Heat Pump | 54,000 BTU Compressor is part of a logic of durability, both mechanically and energetically.


Switch to a controlled, multi-zone HVAC solution

For residential, commercial, or multi-unit projects in Montreal , Laval , Longueuil , on the North Shore or South Shore , contact AirGreen . We will offer you a complete analysis, meticulous installation, and genuine support from the initial call to after-sales service.