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Cooling & Heating · Garage & WorkshopGarage Mini-Split Installation
Garage mini-split installation gives a workshop, home gym or detached garage both heating and cooling from one ductless unit, with no gas line and no vent through the roof. A single-zone system runs $4,000–$7,000 installed. Choose a cold-climate model, which adds $500–$1,500, if the space will be heated all winter and not only on the days you use it.
A garage is the hardest room on the property to condition, and the reason is the overhead door. A double door is roughly ten square metres of thin steel with a leaky perimeter, and each time it opens the air you paid to heat or cool is exchanged for outdoor air. Add a bare concrete slab and, in many 1970s–90s subdivision garages, exterior walls with no insulation at all. Rules of thumb written for houses undersize a room like that every time.
An insulated, drywalled two-car garage with an insulated door commonly lands on a 12,000 to 18,000 BTU unit. The same garage with bare studs, an open ceiling and an uninsulated door can need twice that and still struggle in January. We size from the wall and ceiling insulation, the door, the slab, the ceiling height and the use: a gym held at 18°C all day is a different load from a workshop warmed up on Saturday morning. Often the cheapest capacity is weatherstripping and an insulated door, and we will say so before quoting a bigger unit.
Every mini-split needs its own circuit and an outdoor disconnect, installed by a licensed electrical contractor under an ESA notification. An attached garage usually has a short run to the panel. A detached garage fed by one lighting circuit is a bigger job, because a new feed has to be trenched or run overhead to a small sub-panel first, and the electrician quotes that separately. For a space heated all winter the unit should be a cold-climate model, which keeps heating down to about −25°C at reduced output, mounted on a wall bracket above the snow line.
Against a gas unit heater, a mini-split wins on three counts: it cools in July, it has no burner or vent, and it needs no gas line. A gas heater wins on raw heat in a leaky shop with the door opening all day, and on recovering fast from a cold start; if that describes your garage, see garage heater installation. In a woodworking shop, mount the head away from the dust source and plan to wash the filters weekly, because fine sawdust mats a coil faster than anything in a house. The equipment itself is the same as on our ductless mini-split installation page.
A garage mini-split fits when
- The garage is insulated, or will be before the unit goes in
- You want air conditioning for a gym or workshop as much as you want heat
- There is no gas line at the garage and running one means trenching
- The space is used for hours at a stretch with the door mostly closed
- You would rather not have a burner and a vent in the room
How it works
We check wall and ceiling insulation, the door, the slab and the panel, then pick a head position high on a wall, clear of the door tracks and shelving, and an outdoor position clear of the driveway and snow piles.
The circuit and disconnect go in under an ESA notification. Then the wall bracket, the line set through one cored hole, the drain, a nitrogen pressure test and a deep vacuum before the refrigerant is released.
Heating and cooling are both run and measured before we leave, and you are shown the filter, the remote and the minimum-heat setting if your model has one. To start, send us the garage dimensions and a photo of the panel.
Brands: Cold-climate ductless lines from Mitsubishi, Fujitsu and Daikin are the usual choices for a garage heated through an Ontario winter, and we service other ductless brands as well.
Common questions
Can a mini-split keep my garage just above freezing?
Most wall heads will not set below about 16°C in heating mode. Several manufacturers offer a minimum-heat or freeze-protection setting that holds roughly 8 to 10°C, which is what you want for protecting paint, tools and a parked car without heating to room temperature. Say so at the quote, because that feature decides the model.
Does my garage need to be insulated first?
It does not have to be, but an uninsulated garage costs more to equip and far more to run. Insulating the walls and ceiling and fitting an insulated door can bring the required capacity down a size or two. If the space is used only occasionally and will stay uninsulated, a gas unit heater is often the more sensible recommendation for heat.
Can I still park a car in a garage with a mini-split?
Yes. The head mounts high on a wall and the outdoor unit sits outside, so nothing is in the way of a vehicle. One caution: a mini-split recirculates and filters the room air. It brings in no fresh air and removes no exhaust, so never idle an engine with the door shut.
Can I extend my house furnace ducts into the garage instead?
No. Building-code rules keep the house's forced-air system separate from an attached garage so that exhaust and fuel vapours cannot be drawn into the living space, and the furnace was never sized for the extra load. A garage needs its own equipment, which is exactly what a single-zone mini-split is.
How long does a garage installation take?
The mini-split is usually a one-day job once power is at the garage. Electrical work for an attached garage is often done the same day; a new feed to a detached garage can take a separate visit beforehand. How long mini-split installation takes goes through the day step by step.