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Commercial · Auto Repair Shops & Body ShopsAuto Repair Shop & Body Shop HVAC
Heating bays whose doors open all day is the core of auto repair shop and body shop HVAC, and the equipment choice follows from the doors: low-intensity infrared tube heaters where they cycle constantly, gas unit heaters where they mostly stay shut. Around the heat sit two code-driven systems — vehicle exhaust removal with CO and NO2 detection and, in a body shop, heated make-up air for the paint booth. Every gas appliance in a repair garage is installed to the mounting-height and clearance rules of CSA B149.1 by a TSSA-licensed technician.
A unit heater warms air, and the air leaves the moment a bay door goes up. An infrared tube heater warms the slab, the hoists and the people under it, so the bay feels workable again soon after the door closes because the mass stayed warm. Our rule: if the doors open more than a few times an hour, put infrared over the bays, and keep unit heaters for the parts room, the detail bay or a shop with a single door, where they cost less and do the job. Many shops end up with both, and the infrared tube heater and commercial unit heater pages cover each one in detail.
A repair garage is a place where gasoline vapour can collect near the floor, and the gas code treats it that way. CSA B149.1 sets a minimum height above the floor for any appliance component that could ignite a flammable vapour, and each heater's rating plate lists certified clearances to combustibles that must be held to the sides, above and below. The clearance that gets missed is the hoist: a tube heater that clears the floor by plenty can be too close to a van roof at full lift height. We lay heaters out against the hoist positions and the tallest vehicle the shop services.
Running engines indoors is the other half. Tailpipe extraction — a hose on a drop or a reel, connected to an exhaust fan — takes the exhaust out at the source, and general exhaust fans handle what escapes. The Ontario Building Code sets ventilation requirements for repair garages, and CO detection for gasoline engines, with NO2 detection where diesels are serviced, can be interlocked so the fans ramp up when gas levels rise instead of running flat out all winter. Every cubic foot those fans remove has to be replaced, which is why a shop with strong exhaust and no make-up air has doors that fight you and heaters that struggle to vent.
Body shops add a paint booth, and a booth sends a large volume of air straight outside whenever it sprays or bakes. That air has to come back in heated, or the shop goes negative and dust gets pulled across wet paint. Where solvent vapours are present — the mixing room, prep areas beside the booth — heaters must be separated-combustion types that draw their combustion air from outdoors through a sealed duct, in line with the Ontario Fire Code's rules for spray operations. Start with commercial HVAC for how we quote, or contact the shop and tell us how many bays and doors you have.
Equipment we install and service
A gas burner firing into a steel tube under a reflector, hung along the bays and aimed at the floor. It heats surfaces instead of air, which suits high ceilings and open doors, and it needs its clearance below kept clear of raised vehicles, stored tires and parts racks.
Suspended fan-forced heaters for enclosed areas. Sanding and body-filler dust coats the burner and heat exchanger of a standard unit quickly, so a body shop gets separated-combustion models that take their combustion air from outdoors and keep shop air out of the flame.
Hose drops or reels at each bay tied to a dedicated fan, plus wall or roof fans for the room. Crushed hoses, seized reels and a worn fan belt are why a system that worked on day one captures very little five years later.
Sensors mounted where the manufacturer specifies, wired to start or speed up the exhaust and make-up air at set gas levels and to alarm above them. Sensor elements drift and have a finite service life, so calibration and replacement dates belong in a log an inspector can read.
What goes wrong in these buildings
- The bay doors are up every ten minutes and the techs work in parkas from December to March.
- The unit heater in the corner runs all day and the floor under the hoists is still ice cold.
- By mid-afternoon in winter the shop is hazy and half the crew has a headache.
- Dust lands in fresh clear coat every time the booth fans start.
- An inspector asked for the gas detector calibration record and I do not have one.
- The heater over bay three locks out and needs a reset on every cold morning.
How it works
Door count and how often they open, hoist positions and full lift heights, ceiling height, existing gas line capacity and what the exhaust fans are actually moving. Diesel work, welding and any spray or mixing areas are noted because each changes the equipment list.
Heaters are sized and placed, then exhaust and make-up air are matched so the building sits close to neutral with the fans running. Quoting heat alone for a shop with unbalanced exhaust produces new heaters that lock out for the same reason the old ones did.
Work moves bay by bay so the other hoists keep earning. Gas piping is pressure-tested, each heater is fired and its combustion checked, the detector interlock is proven with the fans, and the clearance labels and maintenance log stay with the shop.
Common questions
Can a tube heater be mounted above a vehicle hoist?
Yes, provided the certified clearance below the heater is still met with the tallest vehicle at full lift height. Where it is not, the heater is moved between hoists, raised, or fitted with the manufacturer's deflector or shield kit, which changes the listed clearance. Nothing combustible gets stored inside that zone, including tires stacked on a mezzanine.
Does a repair garage need a CO detection system?
It depends on how the ventilation was designed and permitted: some shops ventilate continuously at the full code rate, others run lower and rely on gas detection to bring the fans up. Diesel service adds NO2 sensing. If staff have headaches or the air looks hazy, shut the engines off, open the doors and have the ventilation checked before the next shift.
Do you service the paint booth itself?
We work on shop heating, general exhaust, building make-up air and the gas piping that feeds the booth. The booth cabin, its filters, cure controls and its own air make-up unit are best serviced by the booth manufacturer's dealer, who carries the parts and the certification paperwork. We will tell you which side a problem sits on before anyone bills you for guessing.
Why does my shop heater keep locking out?
In a garage the two usual causes are building pressure and dust. Exhaust fans without replacement air pull the shop negative, the heater cannot vent and its pressure switch opens. Grinding and sanding dust also fouls the burner and flame sensor. Snow or a nest blocking the vent, and low gas pressure when every appliance fires together, come next.
Related
Keep the building running.
One licensed team for installs, maintenance contracts and 2 AM calls.