LG

LG MULTI F R32 7-Zone Heat Pump | 48,000 BTU Compressor

In stock
SKU: UMXB481A
Provincial Subsidy (LogisVert): 1690 $ (Updated: November 26, 2025)
Model Number (External): UMXB481A
AHRI: 215402339
ENERGY STAR®: Yes
ENERGY STAR® (Cold Climate): No / No
# ENERGY STAR ID: 3621273
Heating Capacity: -16 °C
Cooling Capacity: 48,000 BTU
Gas (Freon): R-32
WiFi: Included

SEER2 (Seasonal Air Conditioning Efficiency)

1 20.5 30

HSPF2 (Seasonal heating efficiency)

1 9.5 15

EER2 (Instantaneous efficiency in air conditioning)

1 12.8 20

COP at -8 °C (Heating energy efficiency)

1 2.17 3
Nominal Power: 48,000 BTU
Power at -8°C: 33800 BTU
Power at -15°C: 37800 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: 7 Areas
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

When a single outdoor unit has to manage multiple spaces, without compromising on comfort

In Greater Montreal, "easy" buildings are rare. At AirGreen , we work weekly on Montreal duplexes and triplexes, split-level houses in Laval , new constructions in Longueuil , bungalows on the South Shore , and properties more exposed to the wind on the North Shore . One reality consistently emerges: comfort is not uniform from room to room, nor from floor to floor. Between sunlight, insulation, air volume, space usage, and humidity, a single central thermostat almost never reflects real-life living conditions.

This is precisely where the LG MULTI F R32 7-Zone Heat Pump | 48,000 BTU Compressor ( UMXB481A outdoor unit) becomes a high-impact solution. It allows you to create zoned comfort , using a single outdoor unit to power multiple indoor units, while maintaining optimal performance and control. The desired result is not simply "heating and cooling." It's about stabilizing temperature variations, improving dehumidification, reducing temperature conflicts between floors, and offering a simpler daily experience: each zone has its own setpoint, and the system adjusts accordingly.

We also see another major advantage in this type of configuration: when a building is renovated in stages (one floor this year, another next year), a well-designed multi-zone system offers flexibility while avoiding the need for two or three outdoor units. This is a very practical consideration for narrow courtyards in Montreal, regulated facades, or areas where aesthetics and the surrounding neighborhood dictate more discreet choices.


What "7 zones" means in real life

A 7-zone system isn't just about "putting a head in every room." Its real benefit, when intelligently designed, is to:

  • Reducing the temperature differences between floors : a ground floor can remain stable without overheating the rooms.

  • Adapting comfort to occupancy : office during the day, bedrooms at night, living room in the evening.

  • Managing problem rooms : solarium, very active kitchen, bedroom above a garage, damp basement.

  • Improve humidity control in summer, especially in areas where the air stagnates.

A common example: in some duplexes in Villeray–Saint-Michel–Parc-Extension , the living room and kitchen (with south-facing windows) quickly become uncomfortable in the spring, while the upstairs bedrooms remain cooler. In a house in Brossard , the opposite is often seen: a basement that is more humid and cooler than the rest of the house, with a sustained demand for dehumidification in the summer. In both cases, multi-zone climate control allows for a more precise response, without forcing the entire building to follow the same logic.


The equipment at a glance: what you get with the UMXB481A

Your product sheet contains key information that immediately guides the planning process:

  • Cooling capacity: 48,000 BTU

  • Rated power: 48,000 BTU

  • Zones: 7 zones (with a maximum capacity of up to 8 zones depending on the configuration)

  • Gas: R-32

  • WiFi: included

  • ENERGY STAR®: Yes

  • AHRI: 215402339

  • Heating capacity indicated: down to -16 °C

  • Voltage: 220 V

  • MCA: 34 A

  • MOP: 40 A

  • Outdoor noise level: 55 dB(A)

  • Warranty (compressor – parts – labor): 10-10-0 years (extended warranty available)

The dimensions shown are also useful from the outset, because they influence the placement:

  • Outdoor unit: 37.41 x 15.66 x 54.34 in

  • Indoor unit(s): dimensions vary depending on the model chosen (e.g., compact wall-mounted unit around 32.94 x 7.56 x 12.13 in., depending on the head)

Finally, your page lists several compatible indoor unit models (depending on the project design): KNUAK091A, KNUAK121A, NUAK181A, KNMAB071A, KNUAB091A, KNUAB121A, KNMAB151A, KNUAB181A, KNMAB241A . This diversity is an advantage: the indoor units can be adapted to the specific needs of each room (small bedroom, open space, more demanding room, etc.), instead of imposing a single solution everywhere.

At AirGreen , that's exactly what we do when we conduct an assessment: we don't "randomly" choose a head unit for each room. We size the unit based on the volume, the intended use, the building envelope, the sunlight, and the actual behavior of the occupants.


What makes the difference on a multi-zone project in Montreal, Laval and on both shores

1) The design of the refrigeration network: the part that no one sees, but which decides everything

In a multi-zone system, performance depends not only on the brand or BTU rating. It depends heavily on the network design: routes, lengths, elevation changes, distribution, and accessibility. This is where stability, reliability, and ease of service are determined.

On-site, in a Rosemont–La Petite-Patrie triplex, one often has to work around obstacles: load-bearing walls, stairwells, areas where pipes shouldn't be exposed, and finishing constraints. In a Laval (Fabreville) house, one wants to avoid unnecessary runs through a cold garage or crawl space. On the North Shore , some properties require walkways protected against ice and snow accumulation. These aren't minor details: they are the elements that distinguish a "correct" installation from a truly sustainable one.

At AirGreen, we favour a structured approach:

  • Clear identification of the drilling paths before drilling.

  • mechanical and aesthetic protection (pipe covers, clean fixing, consistent passages),

  • maintainable access (no elements buried behind finished ceilings),

  • Smart margin for future service.


2) The BD Unit (distribution unit): the "silent" part that must be flawless

In a multi-zone system, refrigerant distribution doesn't happen by magic. The distribution unit (often called a BD Unit ) plays a central role: it distributes the refrigerant to the indoor units.

This component directly influences:

  • the simplicity of the network,

  • the ability to diagnose quickly,

  • accessibility during an interview,

  • the quality of the finishes (and the actual cost of a future service).

In a project in Boucherville , we deliberately relocated the planned location of the BD Unit so that it could be accessed without opening up finished ceilings. This required a bit more planning during installation, but it avoids lengthy and costly interventions later on. In a property in Saint-Eustache , we also chose a location that minimizes sound transmission to an adjacent bedroom. The goal remains the same: to preserve everyday comfort and keep the system user-friendly in the long term.


3) The logic of BTUs in multi-zone systems: avoid the most costly mistake

A common misconception is that the total capacity of all indoor units will be available everywhere, all the time, simply adding them together. A multi-zone system distributes overall capacity according to demand and priority. If several zones require high power simultaneously, distribution becomes critical.

That's why, at AirGreen, we talk about design and not just assembly. We identify:

  • priority areas (living room, kitchen, master bedrooms),

  • secondary areas (office, spare room),

  • the periods of use (day/night),

  • the "sensitive" rooms (large windows, average insulation, room above a cold space).

In a house in Longueuil , for example, a front office was unused in the evenings. We adjusted the zoning strategy: lower temperature settings at night, and priority given to the bedrooms. The result: improved comfort and more consistent energy consumption, without unnecessarily oversizing.


4) Acoustic comfort: a good multi-zone system should also remain discreet

Multi-zone systems are often chosen for their aesthetic appeal (a single outdoor unit) and for comfort. However, comfort includes noise.

Your product sheet indicates an outdoor noise level of 55 dB(A) , and the indoor units can operate at very low levels (e.g., 29 dB(A) depending on the model). To ensure these figures translate into actual noise levels on-site, the following factors must be considered:

  • the location (avoid under a bedroom window, avoid corners that amplify reverberation),

  • the supports (wall mount or suitable floor base, with vibration reduction),

  • clearances (actual airflow, access to defrosting, space for service),

  • the quality of the fixing (a poorly chosen support can transmit vibrations to the wall).

In many densely populated areas of Montreal, yards are shared, neighbors are close, and a poorly positioned unit can become a source of friction. We integrate this from the planning stage: customer comfort, respect for the neighborhood, and accessibility for maintenance.


5) Electrical: Plan carefully to avoid unforeseen problems

Your datasheet indicates MCA 34A and MOP 40A , with a 220V power supply. In practice, this means you need to check:

  • the capacity of the electrical panel,

  • the space available for a suitable circuit breaker,

  • the path to the unit (clean, secure, compliant),

  • and the location of the sectioning box.

At AirGreen, we validate these elements before finalizing the offer. This step supports a key promise: a smooth installation, without any "surprise additions" because an electrical detail was overlooked.


6) R-32 and commissioning: the rigor that protects performance

R-32 refrigerant is part of a newer generation of HVAC systems. For the customer, this often means modern technology and a solution better aligned with market developments. For installation, this requires constant attention to detail.

  • Perfect seal of the fittings,

  • serious and documented vacuum drawing

  • respecting lengths and configurations,

  • checks at start-up (pressures, temperatures, reactions of zones).

Commissioning is not a formality. On a multi-zone system, it is the moment when it is confirmed that each zone responds correctly, that the distribution is stable, and that the system does not compensate for a design flaw with unnecessary cycles.


7) Wi-Fi and control: useful for comfort, but especially for consistency of use

Your page mentions WiFi included . In reality, the main benefit is to achieve more disciplined management:

  • realistic instructions,

  • Flexible hours

  • better stability (fewer extreme variations),

  • reduction of "conflicts" between zones.

We often see customers who alternate between very low and very high temperature settings, or who switch the heating on and off too frequently. With a multi-zone system, a stable and consistent strategy improves comfort and can limit energy consumption. During the handover to the customer, we clearly explain how to use the system to achieve the best results, without unnecessary complexity.


AirGreen field experiences: real-life scenarios where this 48,000 BTU multi-zone heater changes everyday life

Scenario 1: Triplex in Montreal with asymmetrical floors

In a triplex, each floor behaves differently. The top floor accumulates heat, the middle floor is often more stable, and the ground floor sometimes experiences heat loss (colder floor, drafts). A well-configured multi-zone system allows for compensation, zone by zone, without forcing the entire building to follow a single logic.

Scenario 2: Family home in Laval with teleworking

An office used all day should remain comfortable without turning the entire house into "office mode." With a multi-zone system, you maintain a stable temperature in the office area while keeping other areas on a lighter setting, then rebalance in the evening.

Scenario 3: South Shore, damp basement in summer

In many bungalows, the basement doesn't need "intense cooling," but it does require better humidity control. A dedicated, well-regulated area improves comfort and can reduce musty odors, while preventing the upper floors from becoming too cold.


Common mistakes to avoid (and what we do differently)

Mistake 1: Choosing a multi-zone system without a zoning plan

Placing interior units everywhere without a strategy creates rooms that clash with each other. We build a zoning logic based on use, volume, and the building envelope.

Error 2: Neglecting access to the service

An installation can look "beautiful" on day one, but become a nuisance when maintenance is required. We prioritize clean and accessible routes, and we avoid locations that require dismantling finished ceilings.

Mistake 3: Underestimating the importance of supports and location

Noise and vibration are rarely a brand-specific issue. They almost always stem from poor placement, inadequate support, or insufficient clearance. We consider this a key element of comfort.

Mistake 4: Leaving the electric one until last

When electrical work isn't planned from the outset, the construction slows down, and the client is subject to rushed decisions. We validate electrical feasibility during the estimation phase.


Why choose AirGreen for a 7-zone LG Multi F R32 setup?

Choosing a multi-zone system like this means choosing a solution that is heavily dependent on design and installation quality. At AirGreen , our approach is distinguished by:

  • a free on-site assessment based on the actual condition of the building.

  • concrete planning of the zones and the network,

  • clean and durable finishes,

  • a rigorous commissioning process,

  • clear guidance on usage and settings.

Your page highlights important commitments: transparent pricing , no deposits , and professional refrigeration technicians . This is exactly the philosophy we apply to multi-zone systems: a clean, well-explained, coherent, and maintainable project.


Conclusion

The LG MULTI F R32 7-Zone Heat Pump | 48,000 BTU Compressor (UMXB481A) is a particularly relevant solution when you want zoned comfort , a single outdoor unit, and a configuration adapted to the realities of Montreal, Laval, Longueuil, the North Shore, and the South Shore . Well-designed, it transforms everyday life: more stable temperatures, better-balanced rooms, and more logical humidity control in summer.

Contact AirGreen today for a 7-zone configuration recommendation and a free on-site estimate. Call 514-316-2973 or email sales@airgreen.ca for a clear quote and planning tailored to your building.