One simple detail can turn an ordinary air conditioning installation into a truly efficient, quiet, and long-lasting system. At AirGreen, we've often been called in to fix mistakes made by other installers — and nearly every time, the issue comes down to the same overlooked factor: the refrigerant charge level, combined with improper refrigerant line lengths. This isn’t a coincidence or an isolated case — it’s a widespread flaw in the HVAC industry, even among well-established companies.
What most installers neglect: refrigerant charge and line length
In a wall-mounted heat pump or air conditioner installation, refrigerant gas plays a critical role. Yet many technicians don’t take the time to properly calculate the length of copper lines or adjust the refrigerant charge accordingly. The result: overheating, poor performance, high energy consumption, and even early compressor failure.
Why this mistake is so common
Most technicians rely on the standard lengths listed in installation manuals without tailoring the setup to the actual site. This often happens when:
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The outdoor unit needs to be placed further away due to architectural constraints (balcony, backyard, flat roof).
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Bends or detours are added to the piping layout.
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There's a height difference between the indoor and outdoor units.
In all these cases, the refrigerant charge needs to be precisely adjusted to the actual line length. Yet many simply leave the factory charge as is.
Case Study: Heat pump installation in Longueuil with FUJITSU KZAH R-32
For a residential customer in Longueuil, we installed a FUJITSU KZAH R-32 wall-mounted heat pump, 18,000 BTU — a model known for its reliability, quiet operation, and compatibility with R-32 refrigerant, which is more eco-friendly and efficient.
Project challenge
The outdoor unit had to be installed at the back of the building — over 15 meters away from the indoor unit located in the front living room. The previous installer failed to account for this and left the factory refrigerant charge untouched, which led to:
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Poor cooling performance.
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Intermittent noise from the indoor unit.
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Abnormally high electricity usage.
Our approach at AirGreen
We began by conducting a full technical evaluation:
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Accurate measurement of refrigerant line lengths, including precise bends.
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Verification of the refrigerant charge using an electronic scale.
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Addition of supplemental refrigerant charge precisely matched to the measured lengths.
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Final testing with infrared thermometry and digital pressure gauges to ensure the system was perfectly balanced.
Result: the client immediately noticed improved thermal comfort, lower energy consumption, and total elimination of annoying noise.
Why this changes everything in your air conditioning system
A precisely adjusted refrigerant charge provides:
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Optimal energy efficiency (higher COP).
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Reduced electricity costs.
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Extended component lifespan (especially the compressor).
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Quieter operation.
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More stable heating and cooling cycles.
It’s a detail that’s invisible to the client — but makes all the difference in the long term.
Our standard on every project in Montréal, Laval, Longueuil, North Shore and South Shore
At AirGreen, we apply this meticulous process to every heat pump, central system, and wall-mounted air conditioner installation:
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Use of calibrated electronic scales.
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Brazing under nitrogen to prevent internal oxidation.
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Leak testing with dry nitrogen at 300 psi for 30 minutes.
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Vacuum using a dual-stage pump down to 500 microns.
This isn’t an optional step — it’s our standard, whether for a residential home in Laval or a commercial building in Brossard.
The consequences of a careless installation
Unfortunately, we’re called several times a week to diagnose systems installed incorrectly by others:
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Premature compressor failure due to low refrigerant levels.
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Communication errors between circuit boards.
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Poor home comfort (temperature swings, cold zones).
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Ineligibility for government rebates due to non-compliance.
The importance of the right installer: what AirGreen guarantees
When you choose AirGreen for your air conditioning or heat pump project in Montréal, Laval, Longueuil, the North Shore or the South Shore, you get:
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A certified installer with decades of experience.
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Rigorous project tracking with photos, performance tests, and full documentation.
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Access to top government grants (up to $2,172 through Hydro-Québec’s LogisVert program).
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Fast and efficient after-sales support.
Our practical recommendations for homeowners
Before choosing your heat pump or installer, ask the right questions:
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Is the refrigerant charge adjusted based on actual line length?
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Does the technician use a precise vacuum gauge?
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What’s the leak testing protocol?
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Does the installation meet rebate eligibility criteria?
A good product poorly installed will never deliver satisfaction. A good installer with the right system — that’s the key to lasting comfort.