LG Central Heat Pump LGRED R32 | 3.5 Tons - 42,000 BTU

An LG power plant designed for the real climate here

In Greater Montreal, choosing a central heat pump is never just about the BTU rating. A central system must perform in very real-world conditions: the heavy humidity of July, temperature variations between floors, freeze-thaw cycles, sometimes aging ductwork, homes renovated in stages, and, above all, high expectations for comfort. The LG LGRED R32 Central Heat Pump | 3.5 Ton – 42,000 BTU fits perfectly into this framework: a reliable central solution capable of offering a balance between performance, comfort, and efficient heating and cooling management.

At AirGreen , we've been installing and maintaining HVAC systems in Montreal , Laval , Longueuil , the North Shore , and the South Shore for years. We know that a central unit can be remarkable… or disappointing, depending on one key factor: the quality of the installation, the settings, and the integration with the ductwork. Our approach is to translate a technical specification into measurable results in your home: more stable temperature, better airflow, reduced humidity in the summer, and reliable operation when winter arrives.

The product, in plain terms (what your figures mean in real life)

On your product page, this LG control unit stands out due to key parameters:

• Size/capacity : 3.5 tons , 42,000 BTU (cooling)

• Refrigerant : R-32

• Exterior model : KUSXA421A

• Interior model : KNSLB421A

• AHRI : 215588569

• Advertised heating capacity down to -25°C

• Wi-Fi : optional

• Noise level (outdoors) : 56.0 dB(A)

• Noise level (indoors) : 36 / 41 dB(A)

• Dehumidification : 7.9 pt/h

• Piping : 3/8 – 5/8

• Voltage : 220V

• MCA : 32A

• MOP : 40A

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

• LogisVert subsidy : $0 (updated: November 26, 2025)

Our role is not to repeat this data: it is to explain to you how it translates into comfort, energy consumption, reliability, and peace of mind.

Why R-32 changes the discussion (and why the installation must be flawless)

R-32 is increasingly present in the HVAC world. For the building owner, the benefit is simple: they are following the market's shift towards more modern refrigerants. For the installer, this requires even more rigorous on-site procedures: airtightness, proper brazing practices, pressure testing, careful vacuuming, and complete commissioning.

At AirGreen , we emphasize this point because a power plant, unlike some more “tolerant” systems, quickly reveals any installation weakness:

• Incorrect charging or a micro-leak can impair performance.

• Poor drainage management can create damage or odors.

• Improper airflow adjustment can cause noise, discomfort, and premature wear.

The product is important, yes. But the execution is just as important.

What the owners really want: stability, uniformity, and a “pleasant” atmosphere

In our experience in Montreal and the surrounding areas (including Laval , Longueuil , North Shore , South Shore ), requests often come in three forms:

1. “Some rooms are always warmer or colder.”

2. “In the summer, it’s 'humid' even if the air conditioning is on.”

3. “I want a system that is reliable, quiet, and easy to manage.”

A well-installed and properly adjusted central unit is designed precisely for these objectives. The LG LGRED, with its central format and features, becomes an excellent base… provided that the network (ducts, air returns, controls, drainage) is handled with care.

A concrete example from AirGreen: when comfort changes without "turning up" the thermostat (Montreal)

We completed an installation in a Montreal property where the owner was complaining about a common problem: a house that seemed "okay" on the thermostat, but uncomfortable in several rooms. The old system blew strong air in some areas and lacked consistency in others. In the summer, the humidity remained high, creating a stuffy feeling.

Our approach was pragmatic:

• inspection of ducts and identification of restrictive sections;

• improved sealing (air leaks are often invisible);

• air return check (the “lung” of a power plant);

• validation of drainage and slope;

• commissioning and flow rate settings.

The result: a more uniform feeling of comfort and a “dryer” air conditioning — which often allows you to be comfortable at a slightly higher temperature, therefore with better overall efficiency.

What we (really) check during installation at AirGreen

1) Sizing: the right power for the right building

A 3.5-tonne / 42,000 BTU heater might be ideal for a home… or unsuitable if certain parameters are ignored. Specifically, we evaluate:

• the actual insulation (not just “presumed”);

• fenestration and orientation;

• the floor layout;

• the volume of air to be treated;

• the condition and design of the conduit network.

An oversized unit can cycle too quickly: less dehumidification, more wear and tear, and greater temperature fluctuations. An undersized unit can run continuously during peak periods: comfort drops during extreme conditions. Our goal is a logical choice and stable operation.

2) The ducts: the invisible part that determines 70% of the result

In a central heat pump , the machine itself may be excellent, but comfort is determined by the ductwork:

• crushed or too small conduits;

• “Elbows” and poorly executed transitions;

• air leaks in unsealed sections;

• Insufficient or poorly positioned air returns;

• poorly sized grids.

At AirGreen , we don't treat ducts as a mere detail. We consider them the circulatory system of the home. If the air doesn't circulate properly, the machine works harder, and comfort becomes inconsistent.

3) Airflow and static pressure: the setting that separates a good installation from a remarkable one

Static pressure is rarely discussed in general conversations, but in practice, it's crucial. A ventilation unit needs an airflow rate that's appropriate for your network. If the flow rate is too low: poor performance, risk of freezing in air conditioning systems, discomfort. If the flow rate is too high: noise, a drafty feeling, reduced efficiency.

Our technicians adjust the parameters to target:

• a comfortable breath;

• a balanced distribution;

• consistent efficiency;

• a controlled noise level.

4) Noise: a comfort that can be heard (or that shouldn't be heard)

Your specifications indicate approximately 56 dB(A) for the outdoor unit and 36/41 dB(A) for the indoor unit. In reality, the perceived noise level depends heavily on:

• the location (proximity to a room, a terrace, a resonating wall);

• vibration support and isolation;

• the path of the ducts and the air velocity;

• the quality of the transitions and grids.

We prioritize intelligent positioning and appropriate supports. And inside, we limit sources of whistling by correcting flow bottlenecks and adjusting the network as needed.

5) Dehumidification and drainage: where most of the “minor problems” originate

A ventilation unit doesn't just cool: it also manages humidity. With a claimed dehumidification rate of 7.9 points/hour , this system has the potential to make the air more comfortable—provided that:

• the slope and drainage must be perfect;

• the container and the drainage line must be secured;

• the flow should be tested;

• The installation prevents stagnation (odours) and overflows.

It is often in these details that long-term experience is made. We know this because many service calls in the market come from "half-done" drainage.

6) Electricity: compliance and protection

The control unit requires a 220V power supply, with a 32A MCA and a maximum MOP 40A protection. We confirm:

• the capacity of the electrical panel;

• the conformity of the circuit breaker;

• the gauge of the conductors;

• the overall safety of the installation.

This is non-negotiable: a central system is a major piece of equipment, and a solid electrical base is part of reliability.

7) Commissioning: the final step, often the most neglected

An installation is not “finished” when the machine starts up. It is finished when it is checked , adjusted , and stabilized . Commissioning includes, in particular:

• leak tests;

• vacuum sealing procedures;

• verification of operating parameters;

• validation of drainage under real-world conditions;

• airflow adjustments;

• usage instructions for the owner.

This is also where we explain what people appreciate: how to intelligently adjust the thermostat, when to use certain modes, how to recognize a dirty filter, and how to avoid common mistakes.

Common mistakes we see (and avoid)

• Installing a new power plant on leaking pipes, then concluding that “the machine is not good”.

• Underestimating the return air: a power plant needs to breathe.

• Neglecting the impact of airflow: comfort becomes uneven and noisy.

• Treating drainage as a minor detail: water damage and unnecessary calls.

• Forgetting that the house changes: renovation, adding a room, new windows… and the system must adjust.

Maintenance and best practices: what protects your investment

Even an excellent central heat pump needs smart maintenance. At AirGreen, we always remind you of the steps that prevent 80% of problems:

• Filter : check regularly (depending on usage). A clogged filter increases consumption and reduces comfort.

• Air vents and returns : avoid blocking them with furniture or curtains.

• Drainage : monitor for signs of slow drainage (odour, persistent moisture, droplets).

• Outdoor unit : keep the environment clear (snow, leaves, ice).

• Control / thermostat : avoid extreme variations in setpoint; a central unit likes stability.

We offer tailored HVAC maintenance services because a well-maintained central system can maintain stable performance over the long term.

Real-life scenarios: when this 3.5-tonne vehicle becomes an excellent choice

Without turning every project into a “textbook case”, here are some very common situations where a power plant of this type makes sense:

• Single-family home with existing ducts : replacement of an aging system, with network optimization.

• Renovated property : insulation and windows change the thermal load; the sizing and settings are adjusted.

• Multi-storey house : we aim for better uniformity through balancing, improved air returns and good flow adjustment.

• Demanding owner regarding summer comfort : emphasis is placed on dehumidification, stability and air distribution.

Why choose AirGreen for this LG LGRED R32

Beyond the product, we are implementing a service approach that is both reassuring and proven:

• Free on-site appraisal : because a power plant can't be judged from a photo or over the phone

• Transparent pricing : a final offer before the work begins

• Experienced refrigeration technicians : installation, adjustments, after-sales service

• Payment only at the end : you pay when you are satisfied with the result

• Intervention in Montreal , Laval , Longueuil , North Shore and South Shore

Our goal is simple: a system that works well, for a long time, and that truly improves your daily life. Not just an "installed" piece of equipment, but a system integrated into your home.

In summary: who is this central heat pump intended for?

The LG LGRED R32 Central Heat Pump | 3.5 Ton – 42,000 BTU is for homeowners who want:

• a true central solution for heating and air conditioning;

• better uniformity in the house;

• more efficient humidity management in summer;

• a professional installation, with complete adjustments and commissioning;

• a local service in Montreal , Laval , Longueuil , North Shore , South Shore .

Contact AirGreen
For a quote , a free on-site estimate , or to determine if a 3.5-ton, 42,000 BTU central heat pump is the right choice for your building, contact AirGreen today. We'll offer you a clear, customized HVAC solution, installed to the highest standards, with settings that make a real difference.