Installation of a GREE FLEXX R32 central system in the basement of a home in Lacolle, replacing an electric furnace

The label affixed to the unit contains three pieces of information that almost no one reads

At Lacolle, in the Haut-Richelieu, a few minutes from the border, we replaced an electric furnace with a GREE FLEXX R32 central system. The indoor unit is installed in the home’s original basement: poured and plastered foundation walls, a low ceiling, an uneven concrete floor, and worksite lighting.

This type of space is the most common in the Montérégie rural housing stock, and it is also the one that raises the most genuinely technical questions. Not questions about performance—those are settled by the technical specifications. Questions about refrigerant safety, connection tightness, and the environment around the unit.

At AirGreen, we begin this type of project by reading the manufacturer’s warning label before even choosing the location. On this unit, it lists three requirements that determine whether the installation is feasible. We reproduce them here because they appear in no sales brochure.

First requirement: minimum room area

The R32 is a refrigerant classified A2L, meaning it is slightly flammable. In return for its excellent efficiency and low global warming potential compared with R410A, it imposes a constraint that older refrigerants did not: the amount of refrigerant contained in the system is capped by the size of the space where the unit is installed.

The NOTICE plate screwed onto this unit’s cabinet provides the exact table. Here it is as it appears on the machine:

Two observations worth making.

First, the unit is the kilogram, not the pound. Some commercial sheets in circulation show these same figures under a “lb” heading, making the charge appear three times lighter than it really is. The label affixed to the unit is authoritative. A system charged with 2.9 kg contains approximately 6.4 lb of R32, not 2.9 lb.

Next, the relationship is practically linear: approximately 3 m² of floor area per kilogram of refrigerant. This provides a usable field rule for quotations, even before taking out the tape measure.

What this constraint rules out in practice

The unit installed in Lacolle is a GUD36AH2/G-D(U) 3-ton unit, charged with 2.9 kg. It therefore requires 8.6 m² (92.6 sq. ft.).

A full basement in a rural home exceeds this value by a factor of ten. Compliance is achieved effortlessly. But we regularly receive requests from homeowners who want to place the unit in a 4 ft × 6 ft mechanical closet, or 24 sq. ft. At the required 92.6 sq. ft., this is not a matter of preference or service clearance: the configuration is simply non-compliant, and no installation adjustment can make it compliant.

The technical nuance to understand is that the reference area is that of the served and communicating space, not necessarily that of the small room where the unit sits, because the mitigation mechanism relies on air circulation. A unit enclosed in a closet with solid doors and no adequate return air does not benefit from this communication. A unit in the center of an open basement does.

For the larger units in the range—those charged with 4.6 kg, which require 13.71 m² (147.5 sq. ft.)—this question deserves to be asked before signing the contract, not on the morning of installation.

Second requirement: no ignition sources in the ducts

This is the most important warning on the label, and the one least often followed in the field. It reads as follows: auxiliary devices that could constitute an ignition source must not be installed in the ducts, except for auxiliary devices approved for use with the unit in question.

The practical implication is straightforward. In an all-electric Quebec home, an auxiliary electric heating capacity is almost always added to the central system: an add-on air handler in the plenum or a set of heating elements integrated into the unit. In the R410A era, this choice came down to sizing and electrical load calculations. With an A2L refrigerant, an additional requirement applies: the device must be approved for that specific unit.

A perfectly good electrical heat kit, correctly sized, protected by its limiters, and properly installed may nevertheless be inadmissible in the plenum of an R32 system if it is not among the manufacturer's approved accessories.

Our position on all our R32 projects: auxiliary heating is approved by the manufacturer and distributor before ordering, in writing, with the exact model number of the indoor unit. This five-minute check protects the installation, the warranty, and the building's insurability.

Third requirement: the detection system must remain powered

The label specifies that the installed leak-detection system must remain powered at all times, except during service work.

The FLEXX comes with a factory-installed A2L detection sensor. If a leak is detected, the controller starts the fan to disperse the refrigerant. This mechanism works only if the appliance is powered.

The consequence is ordinary yet frequently overlooked: no one turns off the appliance's circuit breaker during the winter or an extended absence. This is common among owners of cottages and second homes, who are numerous in the Lacolle area and along the border. We put it in writing when handing over the keys.

Flare fittings: where R32 systems leak

On this installation, the indoor unit is connected with flare fittings, in copper, rather than by brazing. The two brass nuts are visible on the right side of the cabinet, along with the red service-port cap on the 3/8-inch liquid line and the 3/4-inch gas-line fitting below.

A flare fitting is faster than a brazed joint and avoids any open flame near an indoor A2L appliance. The trade-off is that it is a mechanical joint, and a mechanical joint deteriorates when the workmanship is imprecise. The vast majority of leaks we diagnose on recent systems occur at a flare fitting, never in the middle of a line.

Our method for a flare that lasts ten years

1. Cut perpendicular to the tubing cutter, without crushing the tube, then deburr with the tube facing downward so copper shavings do not fall into the line. A copper shaving in an electronic expansion valve is a guaranteed service call.
2. Slip the nut on before flaring. It may seem obvious. It is the most common end-of-day mistake.
3. Flaring with an eccentric flaring tool, checked with a flaring gauge: even surface, with no radial cracks or tool marks, and the diameter within specification.
4. A compatible synthetic-oil film on the conical sealing surface, never on the threads. The oil goes on the sealing surface, not on the threading.
5. Tightening with a torque wrench, to the value specified by the manufacturer for each diameter. Not by feel, and not “a little tighter to be sure.” An overtightened flare cracks, and the leak appears six months later.
6. Dry-nitrogen leak test before evacuation, with the joints left exposed—which is why the photo shows a section of bare copper between the insulation and the nut.
7. Insulation sealed over the joint once the test is successful, all the way to the cabinet face, without interruption.

This seventh point deserves particular emphasis in a rural-home basement. The gas line operates below the dew point throughout the air-conditioning season. One centimeter of missing insulation on a connection, and condensation runs along the copper, enters the cabinet, and eventually reaches the concrete. The homeowner concludes that the unit is leaking. It is not, but diagnosing it costs a service call.

The basement itself: what surrounds the unit matters just as much as the unit

The space is an unfinished basement in a rural home. Plastered foundation walls, visible moisture marks halfway up, and a concrete floor with uneven areas. Nothing unusual for the region: the water table is high in the Upper Richelieu Plain, and most of these homes use wells and septic systems.

The supply plenum is insulated, and it is not decorative

In the photo, the supply plenum extending from the unit to the right is covered with foil-faced vapor-barrier insulation. This decision is made when the estimate is prepared, not at the end of the work.

In an unheated or lightly heated basement:

• In heating, an uninsulated plenum loses heat in a space that no one occupies. In a moderately warm-air system, this loss is directly visible in the temperature at the first-floor registers.
• In air conditioning, an uninsulated plenum at 13 °C in a damp basement at 22 °C sweats. Water runs along the sheet metal, accumulates on the joints, stains the concrete, and rusts the sheet-metal screws. Every year, we remove uninsulated plenums whose staples are corroded right through.

The vapor barrier must be continuous and sealed at the joints. Insulation that is installed but poorly sealed at the connections is worse than no insulation at all: it creates a cold surface beneath a permeable layer and concentrates condensation where it cannot be seen.

Condensate without a floor drain

Many of these basements do not have a usable floor drain, or have one whose destination no one knows. On this job, the condensate drain runs down the left side of the unit in an insulated line.

Our rules for this item:

• Trap sized according to the cabinet’s negative pressure, with accessible cleanout plugs that can be reached without dismantling the piping
• Continuous slope, checked with a level, along the entire length
• If a condensate pump is required, it is equipped with a safety contact wired to the 24 V circuit—not merely a sound alarm that no one can hear in the basement
• No direct discharge into a septic tank without validation; in rural areas with a well and septic system, the water’s destination is decided with the owner, not by default

Corrosion over ten years

A painted steel cabinet in a damp basement ages prematurely. We systematically raise the unit off its base, avoid direct contact between the sheet metal and the concrete, and check that nothing is resting against the cabinet. On an uneven floor like this one, leveling is done with shims, not approximation: an out-of-level unit drains its condensate pan poorly, and standing water in a pan is where internal corrosion begins.

Technical data for the system installed in Lacolle

Why Lacolle is a good location for a central heat pump

The Haut-Richelieu area combines three conditions that favor converting from an electric furnace:

• A predominantly all-electric housing stock, with no gas network in most areas, so there is no fuel conversion required and no chimney to decommission
• Ductwork already in place in homes equipped with a forced-air furnace, which considerably reduces the scope of the work compared with a home heated by electric baseboards
• Clear basements that meet the minimum A2L floor-area requirement without any special modifications

The low ceiling and access via a narrow staircase are the only real logistical challenges. A 163 lb cabinet that needs to be taken down to the basement requires planning; it cannot be improvised that same morning.

Eligibility for rebate programs

The system carries ENERGY STAR certification and a certified AHRI number (217120760)—the two documents normally required for the application. We verify actual eligibility before signing, using the exact indoor and outdoor unit combination, because the most common reason for rejection remains a listed efficiency rating that does not match the combination actually installed. Thresholds, amounts and conditions change from year to year and should be verified with up-to-date information rather than a verbal promise.

Mistakes to avoid when installing an R32 system in a basement

• Choosing the unit's location before measuring the space and consulting the label's table
• Installing an unapproved auxiliary heater for the unit in the plenum
• Tightening flare fittings by feel instead of using a torque wrench
• Leaving an uninsulated joint after the leak-tightness test and then attributing condensation to a leak
• Installing an uninsulated plenum in a damp basement
• Cutting power to the unit during the off-season, which disables leak detection
• Placing the unit directly on uneven concrete, without levelling or separation

At AirGreen, we carry out this type of HVAC installation in Lacolle, throughout Haut-Richelieu and Montérégie, as well as in Montreal, Laval, Longueuil, on the South Shore and the North Shore. Whether you need an electric furnace replacement, a central heat pump installation or HVAC maintenance, our team will come to your home, measure the space, review the unit's label with you and provide a quote that reflects what is actually possible in your basement.