Garage Heating Ontario 2026: Natural Gas, Electric, Mini-Split Options Compared

Attached vs detached garage: what changes

The single biggest driver of garage heating cost in Ontario is not the heater itself. It is whether the garage is attached to the house or standing alone in the yard. Attached garages share a wall with the heated envelope, which means less heat loss through the party wall and usually a short, cheap run for gas or electricity. A detached garage is a standalone building, and every utility has to be trenched or run overhead to reach it.[3]

For an attached garage, a natural gas unit heater is typically the lowest total cost of ownership because the gas line is already close by. Electrical service is usually present as well, since the panel is in the house just a few feet away. For a detached garage, you have three realistic options: run a new gas line (expensive), use propane (ongoing tank refills), or go electric with either a resistance heater or a mini-split heat pump.

Ontario garage construction itself costs roughly $30 to $55 per square foot for attached builds and $40 to $70 per square foot for detached, so the structure is already a serious investment before you add heating.[3] Spending another $1,500 to $5,000 to run a gas line to a detached garage often pushes homeowners toward electric solutions instead, especially when the garage is 40 feet or more from the house.

Insulating first: the prerequisite that saves $1000s later

Before you compare heaters, price out insulation. An uninsulated Ontario garage loses heat so fast that any heating system will either run constantly or fail to keep up during a cold snap. The math is brutal: the same heater that keeps an insulated 2-car garage at 18C through January will struggle to hold 5C in an uninsulated one.

Garage insulation in Ontario typically costs $0.50 to $3.00 per square foot installed, or roughly $1,900 to $7,700 for a standard 2-car garage depending on wall, ceiling, and garage-door coverage.[1] The garage door itself is usually the weakest link. Adding an insulated door, or an insulation kit for an existing door, typically adds $200 to $600.[1]

For a working target, aim for R-20 in the walls, R-40 to R-50 in the ceiling, and an insulated garage door rated R-12 or better. A vapour barrier on the interior side is required under the Ontario Building Code for heated accessory structures.[3]

BTU sizing for Ontario winters

Ontario heating load runs higher than most US benchmarks you will see in online calculators, because of our design temperatures (roughly -20C in the GTA, colder further north). The Manual J standard from ACCA is the proper way to size any heating system, and a qualified installer should perform one for anything beyond a simple electric heater.[5] For quick estimates on a well-insulated garage in southern Ontario, a reasonable rule of thumb is 45 to 55 BTU per square foot of floor space.[5]

Ceiling height matters. Every foot above an 8-foot standard increases volume (and therefore BTU requirement) by roughly 10 to 12 percent. Garages with 10 to 12 foot ceilings, or cathedral framing to accommodate a car lift, need a proper load calculation rather than a sq-ft shortcut.

Natural gas unit heaters: cost, venting, gas line

A natural gas unit heater (sometimes called a Modine-style heater after the dominant brand, though many manufacturers make them) is the workhorse of Ontario garage heating. A compact, ceiling-mounted box burns natural gas and blows hot air out a fan. Most are 30,000 to 75,000 BTU, which covers the vast majority of residential garages. Installed cost for a 2-car garage typically runs $2,200 to $4,500 in Ontario, including power venting through an exterior wall.

The catch is the gas line. If the garage is attached and a gas line is close by (say, a furnace or water heater on the other side of the wall), the extension is cheap, often $400 to $900. If the line has to travel 20 to 40 feet or cross floors, expect $1,000 to $2,500. For a detached garage, trenching a buried gas line typically runs $1,500 to $5,000 depending on distance, landscaping, and municipal requirements.

Venting is simple but non-negotiable. Unit heaters require either a direct-vent sidewall termination or a B-vent through the roof, and the installer must follow TSSA gas code clearances.[6] Any new gas appliance in Ontario must be installed by a TSSA-registered gas technician (G2 or G1), and the installation is subject to inspection. Mechanical permit fees for residential gas work typically run $150 to $500.[6]

Operating cost is the advantage. At Enbridge residential rates, a 40,000 BTU unit heater running intermittently to hold 15C in a 2-car garage through an Ontario winter typically costs $150 to $300 per season, far less than electric resistance.

Electric garage heaters: when they make sense

Electric garage heaters come in two basic flavours: 120V plug-in (essentially a beefed-up space heater, usually 1,500W or 5,000 BTU) and 240V hardwired (typically 5,000 to 10,000W, or 17,000 to 34,000 BTU). The 120V units are fine for occasional use in a very small or well-insulated 1-car garage. Anything larger, and you want 240V.

Installed cost for a 240V unit in Ontario runs $700 to $2,000, including the heater itself ($300 to $900) and a new dedicated 240V circuit ($400 to $1,100, more if the panel is full or undersized).[2] All new 240V circuits in Ontario must be installed by a licensed electrician under an ESA notification, and the installation is subject to ESA inspection.[2]

The downside is operating cost. Electric resistance heating is essentially 100 percent efficient at the heater but expensive per BTU because electricity costs more per unit of delivered heat than gas.[8] At Ontario off-peak rates (roughly 8.7 cents per kWh as of early 2026), running a 7,500W electric heater for 4 hours a day in a 2-car garage costs about $75 to $100 per month during the coldest three months of winter, or $225 to $300 per season.[8]

Electric makes sense when: you only use the garage occasionally, gas is unavailable or too expensive to run, and you want the simplest possible installation. It does not make sense for a daily-use workshop unless paired with excellent insulation.

Ductless mini-split for garages

A cold-climate ductless mini-split is the most expensive upfront option for garage heating, but it delivers two things no other single-appliance option matches: summer air conditioning and high heating efficiency. A modern cold-climate unit achieves a seasonal coefficient of performance of 2.5 to 3.5, meaning it produces 2.5 to 3.5 units of heat for every unit of electricity consumed, even in Ontario winter temperatures.[4]

For garage use, a single-zone 18,000 to 24,000 BTU wall-mounted or floor-mounted unit is the typical configuration. Installed cost for a well-insulated 2 to 3 car garage runs $4,000 to $7,500 for a single-zone cold-climate mini-split, including the heater, the outdoor condenser, line set, and a dedicated 20 to 30 amp 240V circuit. See our detailed ductless mini-split cost guide for Ontario for the full breakdown on brand tiers, rebate eligibility, and installation factors.

Three things matter for garage applications. First, always choose a cold-climate rated model (typically designated as Hyper-Heat, XLTH, or similar) rated to maintain capacity at -25C. Standard mini-splits lose significant output below -10C and will struggle in a garage. Second, a floor-mounted head often works better than a wall-mount in a garage because it is out of the way of vehicles and tall storage. Third, verify that the outdoor unit location is protected from direct snow and ice dump from the roofline.

Operating cost is the surprise benefit. For a 2-car garage held at 15C daily, expect $80 to $150 in electricity per winter season, less than half the electric-resistance alternative, plus summer cooling at no extra equipment investment.[4]

Infrared and radiant tube heating

Infrared tube heaters are the quiet overachiever of garage heating. Instead of heating the air, they emit infrared radiation that heats objects and surfaces (floor, workbench, vehicle, occupants) directly. The air only warms up as a secondary effect. For tall garages, workshops, and spaces where the door opens and closes frequently, this is a big advantage because you do not lose your heat every time you open the door.

Installed cost for a typical 40,000 to 80,000 BTU natural gas infrared tube heater in a 2 to 3 car Ontario garage runs $2,500 to $5,500. The equipment is roughly similar in price to a unit heater, but installation is a bit more involved because of the tube length and clearance requirements. Tube heaters need 6 feet of clearance below and 3 to 6 feet to combustibles on the sides. Minimum ceiling height is usually 8 feet; 10 feet is strongly preferred.

Gas line and venting requirements match unit heaters: TSSA-registered installer, mechanical permit, and gas inspection.[6] Infrared tube heaters are particularly popular among mechanics and hobbyists working on vehicles because the heat radiates directly onto the work surface rather than blowing shop dust around.

Electric infrared heaters exist as well (120V or 240V ceiling-mount panels), typically $400 to $1,500 installed, but they are generally only suitable for spot heating over a workbench or seating area, not whole-garage coverage.

Permits, ESA, and gas line requirements

Garage heating in Ontario almost always involves permits. Which permits depend on the fuel type and the total project value.[7]

• Gas permit (TSSA):Required for any new gas-fired appliance. The TSSA-registered installer handles the paperwork and inspection. Typical fee is bundled into the installer's invoice.
• Mechanical permit: Required by most Ontario municipalities for HVAC work valued above $5,000. Residential fees typically run $150 to $500 depending on the municipality.[7]
• ESA electrical permit: Required for any new 240V circuit, any panel upgrade, and any new hardwired electric heater. Contractors file the notification with ESA; the homeowner pays the inspection fee (typically $85 to $175 for a single-circuit job).[2]
• Building permit: Usually not required for installing a heater in an existing garage, but may be triggered if the project involves structural changes or converting unheated space to heated space. Check with your municipal building department.[7]

Toronto residential mechanical permits currently start at a minimum fee of $214.79 (2026 schedule).[7] Ottawa and mid-size Ontario municipalities typically run similar. Avoid the temptation to skip permits; selling a house with unpermitted gas or electrical work is a known deal-killer and Ontario home inspectors routinely flag it.

A practical tip: get quotes from at least three contractors, and ask each one specifically whether the quote includes permits, ESA inspection, gas piping, venting, and any panel or electrical upgrade required. Quotes that leave these out by default can look 20 to 30 percent cheaper on paper and explode once the invoice arrives.

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