Installation of a GREE FREEMATCH R32 two-head wall-mounted heat pump (GWHD(18)ND6MO) in Saint-Édouard, in Les Jardins-de-Napierville

The basement workshop is the least well-served room in the house, and the one we are asked to treat least often

In the agricultural municipalities of Les Jardins-de-Napierville, one home out of three has a basement workshop. Not a hobby corner: a real workshop, with a table saw, a miter saw, a workbench, a compressor, sometimes a wood lathe, and an occupant who spends the winter there. It is almost always the last room to receive HVAC treatment, and it is the one where design mistakes cost the most.

We have already written about Saint-Édouard — a rural home with limited electrical service, where the panel capacity, not the size of the house, determined the choice of compressor, and a second part devoted to setpoint adjustment and the difference between cooling and dehumidifying. That page deals with electrical sizing and summer comfort. This one deals with a specific room and what passes behind its wall. The two complement each other without repeating one another.

What a workshop does to an appliance

A wall-mounted heat pump draws room air in from above, passes it over a heat exchanger with very closely spaced fins, and sends it back out through the bottom. In a living room, this air contains household dust. In a workshop, it contains something else:

• fine wood dust, the kind that remains suspended for hours after the machines are turned off and that the shop vacuum does not capture;
• sanding particles, more abrasive than household dust;
• finishing vapors — dyes, varnishes, oils — that deposit a sticky film on every cold surface;
• metal shavings and splashes in a metalworking shop.

The practical consequence is simple to state and rarely mentioned: in a workshop, the filter does not follow the same schedule as it does in the rest of the house. We are talking about checking it every two to three weeks during periods of intensive use, not a seasonal rinse. And the original washable filter, designed to trap large particles, does not protect the heat exchanger from fine particles: it is the heat exchanger itself that eventually becomes clogged, and at that point this is no longer a fifteen-minute maintenance task.

Our position on these projects: the workshop gets its head, but the customer leaves with a maintenance schedule different from that of the other rooms, written clearly in the project closeout file. An identical unit in two different rooms does not have the same maintenance needs, and claiming otherwise is the best way to lose a heat exchanger within five years.

What a basement does to comfort

A basement behaves opposite to an upper floor.

In summer, it is naturally the coolest part of the house—the slab and buried walls are in contact with ground that remains temperate. The problem in a workshop during summer is almost never temperature: it is relative humidity. Air at 21°C can be very humid, and it is this air that rusts saw tables, warps plywood sheets, and jams workbench drawers.

This is where the behavior of a modulating unit becomes critical. A coil dehumidifies only when it stays below the dew point long enough. A unit that reaches the setpoint in eight minutes and shuts off does not have time to do this work. On this project, the 7,300 BTU/h modulation floor—the lowest in the entire FREEMATCH range—is precisely what allows the unit to run slowly for long periods rather than in short bursts.

In winter, the challenge changes. The slab is cold, stratification is pronounced, and a wall-mounted head blows warm air at two meters above the floor, where it naturally tends to remain. Our guidelines for this type of installation:

• point the deflector downward, decisively, in heating mode—that is the opposite of the summer setting;
• leave the fan speed in automatic mode rather than limiting it, so the unit can circulate the air throughout the space;
• never promise that a wall-mounted head will make an uninsulated slab comfortable underfoot. It will not. A cold floor must be addressed at the floor level.

Where to place the head in a workshop

The available wall in a finished basement is rarely the one you would choose. Our placement rules, in order:

1. Never facing a source of dust. A head that draws air directly above a miter saw will clog its filter within a few weeks. Place it away from the cutting area, and accept that the airflow path will be slightly less direct.
2. Never above a precision work area. A continuous stream of air over a workbench is distracting, dries out adhesives, and moves shavings where you do not want them.
3. Never behind a row of wall-mounted shelves. A head needs unobstructed airflow from above; workshop storage units have a habit of reaching all the way to the ceiling.
4. Always taking the condensate drain into account. A basement often requires a long sloped drain or a condensate pump, and that decision must be made before drilling, not afterward.
5. Always keeping access in mind. A unit that needs frequent dusting must remain reachable without dismantling storage.

The minimum room area, and why we publish no figure

There is one point workshop owners need to know before ordering, because it may disqualify a room.

The label affixed beneath each indoor unit displays, alongside the R32 A2L pictogram, a minimum installation height and a minimum room area. These values are not fixed constants from the standard: they are calculated for each unit based on the circuit's refrigerant charge. That is why two units in the same range may bear two different figures, and why the values circulating in forums and articles mean nothing for your installation.

We covered this mechanism in detail elsewhere in our series, and we will not repeat it here. The rule we take from it is this, and it is sufficient:

The only figure that concerns you is the one printed on your unit.

Why this matters more in a basement workshop than elsewhere: a workshop is often a partitioned room in a shared basement, smaller than it appears once storage is installed, and the back of a basement is exactly where a gas heavier than air would collect. The question of room size must therefore be asked before choosing the room, not discovered after installation. We ask it systematically and refer to the manufacturer's installation manual rather than relying on a general figure.

Do not drill: what runs behind a workshop wall

A workshop has one feature that other rooms do not: you drill into the walls. Shelves, a pegboard, a tool rail, a television mount, a magnetic knife strip, a bolted vise. This is the normal use of the room, and it is why the wall supporting a wall-mounted heat pump in a workshop deserves special treatment.

What actually runs through this wall

Behind the mounting plate of an indoor unit, across a width that often exceeds that of the unit, there is:

• two copper lines — 1/4 in. for liquid, 3/8 in. for gas — beneath insulation;
• a condensate drain pipe, sloped, which can be put out of service by a single crushed point;
• a control and power cable connecting the indoor head to the outdoor unit.

A 2-inch screw driven into the wrong place does not always cause a visible catastrophe. In the best case, it misses everything. In the worst, it punctures a refrigerant line, and the diagnosis will come months later, when the appliance has lost enough charge to stop performing. Let us recall what we repeat on all our jobs: a system that is low on refrigerant has a leak, and adding refrigerant is not maintenance.

A puncture in the condensate drain pipe, on the other hand, reveals itself during the first summer, inside the wall.

The “do not drill” label is not decorative

Among the label pictograms beneath the appliance is a warning not to drill. It refers to the appliance itself—its heat exchanger is a few millimeters behind the sheet metal, and a pierced coil on an R32 circuit is not a repair, but a replacement. We show it to the customer upon delivery, along with the rest of the label strip, because that is the only time anyone looks at them.

The survey we provide

What we do on workshop installations, and what we recommend requiring from any contractor:

• photograph the open wall before closing it, with a tape measure visible in the frame;
• dimension the route on a simple sketch: distance from the corner, floor height, width of the area occupied by the lines;
• hand these two items to the owner with the project closeout file, rather than merely keeping them in our records.

A dimensioned sketch is better than a stud finder in a hesitant hand. We have written elsewhere about locating exterior anchors and taking photos while access is still open; what we add here is that in a workshop, this survey must go home with the customer, because they are the one who will drill that wall, probably within six months.

Before drilling near the appliance

• First locate the exterior pass-through point: it establishes the actual height and alignment of the bundle.
• Allow a generous exclusion zone around and beneath the plate, rather than an optimistic clearance.
• Never use the cabinet, its screws, or its anchors as a mounting point for anything else. An appliance's anchors are reserved for that appliance—this is true both inside and outside.
• When in doubt, a call before drilling costs a few minutes; a drilled line costs a day in the workshop and a recharge.

Installed equipment

We will say it plainly: a pair of 9,000 BTU/h heads on an 18,000 chassis is nothing unusual, either in our series or elsewhere. What sets this page apart is not the technical specifications, but the room served by the second head.

Three particular features nevertheless deserve mention for this capacity class:

• This is the only chassis in the range that accepts only two heads. The others accept three, four, or five. With a GWHD(18), the configuration is final: a third zone cannot be added later without changing the outdoor unit. This must be stated at the time of sale, not discovered two years later.
• Its factory charge covers only 10 m of piping, compared with 30 m on the 24,000 and 50 m on the 42,000. On a 28 m run—a ground floor and a basement on opposite sides of the house—adding refrigerant is the rule, not the exception. These 360 g were weighed on a scale and recorded.
• This supplementary heat source must be recorded with the circuit's total load. Since the label's minimum height and area values are calculated from the load, a final load greater than the factory load is a question to be addressed in the manufacturer's manual, not an administrative detail. We ask it; we do not answer it on the manufacturer's behalf.

Program eligibility

The GWHD(18)ND6MO is ENERGY STAR certified and has a published AHRI number—two routine checks in Quebec financial assistance programs. Requirements depend on the heating system being replaced, the type of building, and the program year, and they change. We do not publish amounts: we validate each file using the documents in effect at the time of signing and prepare the supporting documents at the end of the work.

Saint-Édouard: a Quebec village named after an English king

The place name Saint-Édouard honours Edward the Confessor (circa 1002–1066), King of England from 1042 to 1066. Around 1050, he initiated the construction of the church that would become Westminster Abbey; it was inaugurated in 1065, and he died on January 5, 1066, a few days later. Few farming villages in Montérégie have such an unlikely lineage.

On the ground, the history is more local: part of the territory belonged to the seigneury of Saint-Georges, granted to François Languedoc in 1823. The parish was canonically established in 1829, then civilly in the following years—the municipal and toponymic sources do not agree perfectly on the exact date of the civil establishment, and we prefer to point this out rather than choose one. The post office opened under the name Saint-Édouard-de-Napierville, the current official name was established on December 5, 1968, and the parish municipality simply became a municipality on December 11, 2010. The church houses an 1892 Mitchell organ.

The area covers approximately 53 km² and has about 1,300 residents, roughly fifteen kilometres northwest of Napierville and about fifty kilometres from Montréal. Agriculture is diverse—potatoes, dairy farming, and poultry production—and this is reflected very concretely in our work schedule: many country homes, many basements converted into workshops, and homeowners who repair whatever they can themselves.

At AirGreen, we install and service heat pumps, wall-mounted air conditioners, and complete HVAC systems in Montréal, Laval, Longueuil, on the North Shore, the South Shore, and throughout Montérégie—including the villages of Jardins-de-Napierville: Saint-Édouard, Napierville, Saint-Cyprien-de-Napierville, Sainte-Clotilde, and Saint-Chrysostome. A unit installed in a workshop is not designed the same way as one installed in a living room, and that is precisely the kind of distinction that determines customer satisfaction five years later.