LG LGRED R32 Central Heat Pump | 4 Tons - 48,000 BTU

A central heat pump designed for the realities of Montreal, Laval, Longueuil and our winters

In Greater Montreal, a central heat pump is never “just” a device. It’s a complete system that has to cope with intense heating cycles, rapid temperature fluctuations, freeze/thaw cycles, and summers where humidity can drastically alter indoor comfort if dehumidification isn’t properly managed. At AirGreen, we see the difference in the field between a system that “works” and one that provides true stability: more uniform temperature, controlled noise, and more consistent operation from room to room.

The LG LGRED R32 Central Heat Pump | 4 Tonnes - 48,000 BTU fits into this logic: a 4-ton format (nominal power 48,000 BTU in cooling) for properties that require high capacity, with an R-32 refrigerant and a central architecture (outdoor unit + indoor unit) designed to work with ducts.

Product information that matters to a homeowner (and to a serious installer)

Based on this model, several data points are particularly useful for understanding what to expect:

• Product Name : LG Central Heat Pump LGRED R32 | 4 Ton – 48,000 BTU

• Outdoor unit (model) : KUSXA481A

• Indoor unit (model) : KNSLB481A

• AHRI : 215588577 (useful for identification and certain performance validations)

• Refrigerant : R-32

• Cooling capacity : 48,000 BTU

• Heating capacity : indicated as functional down to -25°C (depending on the unit)

• Voltage : 220V

• MCA : 32A / MOP : 40A

• Outdoor noise level : approximately 56 dB(A)

• Piping : 3/8 – 5/8

• Warranty (compressor – parts – labor) : 10 – 10 – 0 years (labor not included as standard)

• WiFi : optional

• Provincial subsidy (LogisVert) : displayed at $0 (update indicated as of November 26, 2025)

These elements serve as a basis, but the real question quickly becomes: is this the right format for your property, and will your ductwork (or ductwork design) allow the machine to express its performance in a stable and quiet manner?

What “4 tonnes” means in real life

A 4-tonne system isn't limited to a single "house size" on paper. In practice, the need depends on several factors:

• quality of the building envelope (insulation, airtightness)

• windows (glazed surface area, orientation, type)

• ceiling height and actual volume of air to be treated

• interior layout (open area vs. closed rooms)

• existing ducts (diameters, air returns, leaks, attic insulation)

• Occupant habits (target temperatures, times, occupied areas)

In Montreal , for example, we encounter properties where a high capacity is justified as much by the architecture as by the constraints of the ductwork. In some renovated duplexes in Rosemont–La Petite-Patrie or Villeray , we see very positive insulation improvements, but partial ductwork systems, sometimes modified “over the years,” which require a structured approach to avoid imbalances (and therefore discomfort).

R-32 refrigerant: an evolution, and a requirement for rigor

R-32 is one of the newer refrigerants, and its use comes with an unavoidable reality: the quality of the installation, procedures, and controls matters enormously. A properly installed R-32 central heat pump is an excellent modern choice; a poorly installed R-32 central heat pump quickly becomes a source of avoidable problems (unstable performance, charging errors, noise, and unnecessarily long cycles).

At AirGreen, we approach R-32 with a simple logic: a clean, compliant, measured, and documented installation on site, rather than an “by habit” approach.

AirGreen case study: stabilizing comfort in a property with temperature variations

A very common scenario, both in Laval and Longueuil : the property cools down quickly, but the air remains heavy. Or: the upper floor becomes too hot while the ground floor is comfortable, especially on hot days.

In this type of case, we begin by isolating the probable causes:

• Poorly distributed airflow (some duct branches are too restrictive)

• Insufficient air return (the circulation is "not working properly")

• Leaks in the attic ducts (treated air is lost)

• Overly restrictive or poorly adapted filtration

• adjustments and balancing not finalized after installation

Our AirGreen approach:

1. detailed inspection of the ducts (including hard-to-reach areas)

2. fixing leaks and problematic sections

3. improved air return when necessary

4. commissioning with functional validations (heating and air conditioning)

5. concrete recommendations to the client (filters, frequency, points to monitor)

The desired result: fewer fluctuations, a feeling of drier and more stable air in the summer, and more consistent operating cycles. In most cases, the customer feels the difference from the first week, especially during humid periods when the house was previously uncomfortable.

The installation details that make all the difference (and that you don't see in a product description)

1) The ductwork network: the key to comfort in a central heating system

A central heat pump's performance depends on the quality of the distribution network. Two installations can use the same model (KUSXA481A + KNSLB481A) and produce very different results.

Critical points that we systematically check:

• Air returns : size, location, overall circulation

• balancing : preventing one area from "stealing" all the bandwidth

• insulation of ducts in unheated areas (attic, crawl space)

• Sealing : a pipe leak is a direct loss of comfort and efficiency

• Noise : excessive air velocity, poorly designed transitions, undersized ducts

In areas like Ahuntsic or Saint-Laurent , you regularly see houses with existing flues that have been modified during renovations. This isn't a problem in itself, but it requires a thorough assessment before installing a 4-tonne central heating system.

2) The location of the outdoor unit: a “winter” decision

In Quebec, the positioning of the outdoor unit directly influences:

• the accumulation of snow

• defrost water management

• access for service and maintenance

• Air recirculation if the space is too enclosed

• vibrations and perceived noise (depending on the surface and support)

Our AirGreen objective: logical placement, clearances respected, stable support, and planning of defrost water to prevent it from freezing where it is driven.

3) Electricity: safety, compliance, and sustainability

A central electrical installation must be consistent with the building's electrical reality. For this model, references such as 220V , MCA 32A , and MOP 40A are used, which guide the circuit, circuit breaker, and wiring requirements according to applicable regulations. Proper electrical preparation prevents tripping, protects equipment, and ensures overall safety.

4) Drainage, condensation and dehumidification

In air conditioning mode, condensation management is a key issue. A unit of this capacity can remove a significant amount of humidity if everything is properly configured (clean coil, appropriate flow rate, good drainage, and suitable slope and siphon).

We sometimes see installations where:

• The drain is too long without an adequate slope.

• the connection is “more or less” watertight

• Maintenance access is difficult, so cleaning is neglected

At AirGreen, we prioritize installations that remain accessible, inspectable, and durable. A good installation is one that can be easily maintained, year after year.

Performance, maintenance, and realistic expectations: what you need to know before investing

Heating: stability, cycles and perception of comfort

A mention like “heating capacity down to -25°C ” is interesting, but the actual experience depends on several parameters:

• house insulation

• waterproofing

• sizing

• settings and airflow

• defrosting behavior

• quality of the installation

The important point for a homeowner: a good central heating system is not just about “blowing out very hot air”. It maintains a regular temperature without sudden variations, with a more homogeneous air distribution, especially in areas that were historically difficult (bedroom above garage, floor exposed to full sun, finished basement, etc.).

Air conditioning: beyond cooling, humidity management

In Montreal and on the South Shore , summer discomfort is often linked to humidity, not just temperature. A 48,000 BTU unit can certainly provide air conditioning, but an operational approach is needed that allows for:

• sufficiently stable cycles

• good dehumidification efficiency

• balanced air distribution

• suitable and clean filters

This is precisely where installation expertise makes all the difference. Two houses with the same temperature can feel completely different if humidity is not managed properly.

Noise: how to avoid unpleasant surprises

Perceived noise is not just the dB(A) value. It depends on:

• of the air velocity in the ducts

• the quality of the transitions and plenums

• of the fixing of the conduits (vibrations)

• the positioning of the outdoor unit

• of the support used (slab, supports, vibration isolation)

At AirGreen, we take noise seriously, because it's one of the most frequently cited annoyances after a central installation. A powerful system can remain discreet if the fundamentals are respected.

HVAC Maintenance: What We Recommend to Protect Your Investment

A central heat pump is a major piece of equipment. The best way to preserve its performance and durability is to have a clear HVAC maintenance routine.

What we typically cover:

• inspection of the outdoor unit (debris, clearances, general condition)

• checking drainage, condensation and signs of obstruction

• checking the condition of the coil (cleanliness, air circulation)

• Filtration system check (type, condition, replacement frequency)

• review of operating parameters and observation of cycles

• specific recommendations for the owner based on their environment (pets, dust, renovations, etc.)

In neighborhoods like Le Plateau-Mont-Royal or Hochelaga-Maisonneuve , some properties are more exposed to urban dust and fine particulate matter; on the North Shore , there is often more pollen in the spring. The maintenance plan must take these realities into account.

Why choose AirGreen for an LG LGRED R32 4-tonne central heating system?

At AirGreen, our approach is not to “install a machine”. We aim for an installation that meets three simple objectives:

1. Measurable comfort : stable temperature, consistent air circulation, effective dehumidification.

2. Sustainable installation : piping, drainage, electricity and commissioning carried out with rigor.

3. Clear customer experience : concrete explanations, clean work, and realistic maintenance recommendations.

We serve Montreal , Laval , Longueuil , the North Shore and the South Shore , and we adapt the installation to the specific characteristics of each building. A 4-tonne plant has great potential, but this potential is only realized when the entire system (house + ductwork + installation) is properly configured.

Get a free on-site estimate

To find out if the LG LGRED R32 Central Heat Pump | 4 Ton - 48,000 BTU (models KUSXA481A / KNSLB481A ) is the right choice for your property in Montreal , Laval , Longueuil , on the North Shore or South Shore , contact AirGreen. We assess your building, your ductwork, and your comfort goals to offer you a clear, sustainable, and tailored HVAC solution.