Home / Services / Garage Heater Installation
Heating · Garages & ShopsGarage Heater Installation
Garage heater installation usually means a vented gas unit heater hung from the ceiling, exhausted through the sidewall, fed by its own gas line and controlled by a thermostat mounted where a bumper cannot reach it. Done properly it holds a two-car garage at a working temperature through a −15°C week. Done badly it either cannot keep up or puts combustion gases where people and vehicles are.
There are three realistic options and they suit different garages. A ceiling-hung gas unit heater — commonly 45,000 to 75,000 BTU for a two-car space — is the workhorse: forced air, quick recovery, cheap to run on natural gas. An infrared tube heater warms the floor and the objects rather than the air, which is the better choice for high ceilings or a shop where the overhead door opens constantly, because the heat is not lost the moment the door goes up. Electric avoids gas and venting entirely, but a heater with enough output to matter draws serious amperage and often needs a subpanel, which is usually what pushes people back to gas.
A garage is not treated like a room, and the installation rules reflect that. The heater is vented outdoors — never one of the unvented shop heaters sold for temporary use, which dump water vapour and combustion products into a closed space. Where a vehicle parks, the gas code keeps the appliance's ignition source at least 450 mm above the floor, because gasoline vapour is heavier than air and settles low, and both the unit and its piping have to be protected from being struck. Clearances to combustibles are real numbers, not guidelines, and the usual mistake is hanging the heater too close to the overhead door track or the shelf above the workbench.
Insulation decides the size, not the square footage. An uninsulated overhead door and an uninsulated ceiling under a bonus room will beat any heater you can hang, so before choosing a BTU rating we look at the door, the ceiling, the weatherstripping on the man door and the gap under the overhead. For a detached garage — common on the older lots in Ancaster and out toward Binbrook — the job also includes a buried gas run with its own shutoff, which is where our gas line installation work meets this one. A detached garage with its own gas run and a wall-mounted unit heater is the usual package.
One side benefit is worth knowing about. A bonus room or bedroom over an unheated garage is cold because it sits on an uninsulated floor above outdoor-temperature air; heating the garage often fixes that room more effectively than reworking the ductwork upstairs — see why one room is always cold. If your garage doubles as a workshop that also needs cooling in July, a ductless mini-split does both jobs on one system. Ask for a quote and we will size it against your actual insulation.
You want a garage heater when
- The garage is a workshop, gym or hobby space you avoid from December through March
- There is a bonus room or bedroom above the garage that never warms up
- You keep a car, boat or motorcycle you would rather not cold-start at −15°C
- You are running a portable propane or kerosene heater with the door cracked for air
- Paint, adhesives, batteries and stored liquids keep freezing over the winter
How it works
Door, ceiling, walls and air leaks, then the gas supply and the electrical. A sensible heater in an insulated garage beats a big one in a leaky one every time.
Unit hung on threaded rod with the required clearances, sidewall vent terminated clear of doors and windows, gas line run with a shutoff and drip leg, and a thermostat mounted where a vehicle will not hit it.
Combustion checked, safeties tested, and the thermostat set to a low hold — most people run 5°C to 10°C when the space is empty and bump it up an hour before they use it.
Common questions
What size heater does a two-car garage need?
Typically somewhere in the 45,000 to 75,000 BTU range, but the spread is entirely about insulation. An insulated garage with a modern door lands at the bottom of that; a 1960s detached garage with a wood door and no ceiling insulation lands above it and still will not hold temperature on the coldest days.
Can I use an unvented heater instead?
Not as a permanent installation. Unvented combustion releases water vapour and combustion products into the space, which in a closed garage means condensation on everything and a carbon monoxide risk. Every heater we install is vented outdoors.
Gas or electric?
Gas, in most cases, because running cost is lower and the output is higher. Electric makes sense in a small, well-insulated garage with no gas nearby, or where a vent penetration is impossible — but check the panel capacity before you assume it is the cheaper route.
Will it heat the room above the garage?
It helps significantly, because that floor is no longer sitting over outdoor air. It is not a substitute for insulating the garage ceiling, but the two together usually solve a cold bonus room for good.
Can I leave it on all winter?
Yes, and holding 5°C to 10°C costs far less than heating the space to 20°C on demand from freezing. It also protects stored liquids and keeps the concrete from sweating every time you open the door on a mild day.