Unit heaters
Gas and Electric Unit Heaters for Shops, Garages and Warehouses
Installation, repair and annual service for suspended gas-fired and electric unit heaters in shops, garages, warehouses and service bays.
- ScopeInstall, repair and maintain
- FuelGas-fired and electric heaters
- SpacesShops, garages, warehouses, bays
IllustrationScope
Unit heater work, from layout to annual service
- Gas-fired propeller and blower-type unit heaters, plus electric unit heaters
- Separated-combustion and power-vented models compared for dusty or tight buildings
- Mounting height, hanger or bracket rating and discharge direction set for the space
- Clearances to combustibles, stored goods and vehicles read from the heater's rating plate
- Venting and combustion air route, including termination clearances at walls and roofs
- Thermostat placement, zoning and setback programming
- Electric heater circuits and disconnects handled by licensed electrical professionals or trade partners
- Annual service: burner, heat exchanger, fan, ignition, vent and thermostat checks
Process
Unit heater job, from layout to light-off
Every job starts with a conversation and a look at the equipment. You see the options in plain language before anything is booked.
- 1
Measure the space and the heat loss
We look at wall and roof construction, door sizes, how often doors open and what is stored. These drive the load calculation, which sets the heater size and number, not a square-foot rule.
- 2
Pick the heater type and location
Propeller models suit open bays, while blower-type models handle ducts and longer throws. Placement balances heat distribution against clearances, vehicle height and stored materials.
- 3
Plan gas, vent and power
Gas supply, vent route, combustion air and power are mapped before the heater is ordered. Gas sizing is covered on the commercial gas lines page.
- 4
Hang, vent and connect
Heaters are suspended from rated hangers, vented as the manufacturer's instructions require and connected to gas or power. Electrical connections are done by licensed electrical professionals or trade partners, with permits and ESA notification where required.
- 5
Fire up and test
We check gas pressure, ignition, flame, fan operation, venting and thermostat response. A short note records settings and clearances.
In pictures
What this work looks like
Illustration
IllustrationIllustrations and sample pictures. Real Kelvin Mechanical job photos are added as they are collected.
Good to know
Types, placement and where the air is dirty
Propeller versus blower-type
Propeller heaters are common in open bays and warehouses. Blower-type heaters push air further or into ducts and handle more resistance. The right choice depends on layout and throw distance.
Standard versus separated combustion
Standard heaters draw combustion air from the room. Separated-combustion models bring it from outdoors, which suits dusty or tightly sealed buildings. Venting rules vary by model.
Gas versus electric
Gas units need a gas supply and a vent. Electric units need adequate circuit capacity and no vent. Running costs depend on local energy rates and the building.
Garages and contaminated air
Mounting height and clearances follow the manufacturer's instructions and the gas code, which are stricter where vehicles or flammable vapours may be present. Solvents, aerosols, welding fumes and fine wood dust need review before a heater is chosen.
Install, repair, maintain
Installation: placement, venting and clearances
We choose the heater, location, vent route and gas or power supply from the layout and the load. Start-up checks gas pressure, ignition, venting and thermostat operation.
Repair: ignition, fans, venting and controls
Common faults are igniters, flame sensors, gas valves, fan motors and blocked vents. We diagnose first and give written options.
Maintenance: annual service before the heating season
Burners, heat exchangers, fans and vents are cleaned and inspected before cold weather. Dust and lint are a common cause of avoidable service calls in shops.
Tell us what is in the air
Solvents, aerosols, paint spray, welding fumes and heavy wood dust can affect combustion air and ignition safety. Mention them at the first call so the right heater type and location are chosen. Residential-style workshops are covered under garage and workshop heaters.
Ontario notes
Unit heater notes for Ontario shops, garages and cold snaps
Cold snaps and large doors
Ontario cold snaps stress shops and warehouses with big overhead doors. Each time a door opens, the heater has to recover. Heater placement, door location and discharge direction matter as much as total output, so we look at how the building is used through the day.
Gas heaters, venting and codes
Gas-fired unit heaters fall under the gas installation code, the manufacturer's instructions and municipal requirements, with extra rules in garages. Gas work is regulated in Ontario. Permits and inspections depend on the work and the municipality, so we confirm them in the written scope before work.
Electric heaters and electrical capacity
Electric unit heaters avoid venting but draw significant power. The panel, breaker and wiring have to carry the load under the Ontario Electrical Safety Code. Electrical work is carried out by licensed electrical professionals or trade partners, with permits and notification where required.
Fall service timing
Heater calls bunch up at the first cold snap. Booking a fall service visit before then leaves time to order parts, clear dust and fix venting problems. Availability depends on the season and the schedule, and a written note after the visit records what was checked.
Help centre
Questions about Unit Heaters
Can a unit heater replace my old one in the same spot?
Often, if the gas line, vent and clearances still meet the manufacturer's instructions and the code. We check these during the site walk. A new model may need different mounting or venting.
Are gas or electric unit heaters better for a shop?
Neither is always better. Gas suits buildings with gas service and heavy heating loads, while electric avoids venting and suits smaller or intermittent loads. Local energy rates and electrical capacity matter.
How often should a unit heater be serviced?
Usually once a year before the heating season, and more often in dusty or contaminated spaces. Service covers the burner, heat exchanger, fan, ignition, venting and thermostat.
What clearances does a unit heater need?
They are printed on the heater's rating plate and in the installation manual, and the gas code adds rules for garages. We follow both and note the clearances in the service note.
Do you handle the gas line to the heater?
Gas piping is done by licensed gas-fitting professionals, with permits and inspections where required. It is part of the project scope, and you can read more under commercial gas lines.
What size unit heater does a garage or shop need?
Size comes from a heat loss calculation, not floor area alone. Wall and roof construction, door size, how often doors open, ceiling height and the temperature you want all matter. One large heater is not always better than two smaller ones. We calculate the load and suggest a size and layout in the written scope.
Can I install a gas unit heater myself?
Gas work is regulated in Ontario, and an installation involves gas piping, venting, clearances and often electrical connections. Mistakes can create fire or carbon monoxide hazards. Heaters should be installed by licensed gas-fitting professionals, with permits and inspections where required. We scope the full job so every piece is done properly.
Why does my unit heater turn on and off without heating?
Short cycles can come from a failing igniter or flame sensor, a blocked vent, a dirty heat exchanger tripping the limit switch, a weak fan or a thermostat problem. Dust and lint are common causes in shops. If you smell gas, leave the building and call 911 or the gas utility. Otherwise call +1 905-407-7353.
How high should a unit heater be mounted in a garage?
Mounting height is set by the manufacturer's instructions, the code and what is below it, such as vehicles, lifts and stored goods. Heaters in garages have stricter rules than those in open warehouses. Clearances are on the rating plate. We measure the space and note the final heights in the service note.
Do gas unit heaters have to be vented to the outside?
Most gas-fired unit heaters are vented outside, through a flue or vent pipe. Separated-combustion models also draw their air from outdoors. The vent route, termination clearances and combustion air are set by the manufacturer's instructions and the gas code. We map them before the heater is ordered.
Can I use a gas unit heater in a woodworking or auto body shop?
Sometimes, but the air matters. Paint spray, solvents, aerosols and fine wood dust can affect combustion and ignition safety. A separated-combustion model or a different heating approach may be needed. Tell us what the shop does at the first call so the right heater and location are chosen.
What should I do to get a shop heater ready for winter?
Book a fall service before the heating season. Clear dust and lint from around the heater, check the vent terminal for nests, debris or snow, test the thermostat and keep stored goods clear of the rating-plate clearances. A service visit checks the burner, heat exchanger, fan and ignition.
How do I know if a unit heater heat exchanger is cracked?
Warning signs include soot, an unusual smell, a flame that looks wrong, a carbon monoxide alarm or visible cracks. Do not run a heater you suspect is cracked. Turn it off, ventilate the space and book a visit. If a carbon monoxide alarm sounds, leave the building and call 911.
Where we do this work
Unit Heaters in Toronto, the GTA and Hamilton
Toronto Mississauga Brampton Vaughan Markham Oakville Burlington Hamilton All service areas
Quote and booking
Request: Unit Heaters
Share a few details and we will follow up. A written quote comes after a site review. There is no online checkout.
- City and service type help us route your request
- Urgency and property details let us prepare properly
- Optional equipment photos speed up repairs and replacements
Prefer to talk? +1 905-407-7353
Gas smell or carbon monoxide alarm? Leave the building and call 911 first. Do not use this form.