A hydronic unit heater run off your gas boiler can warm a garage or workshop, but freeze protection and standalone loop design need real thought.
Tell us what you need—we’ll call you back fast.
Quick answer
A hydronic unit heater is a fan-and-coil unit mounted on a wall or ceiling that heats a garage or workshop using hot water piped from a natural-gas boiler, rather than burning gas directly at the unit. In an unheated or intermittently heated Metro Vancouver garage, the main design questions are freeze protection for the piping run and whether the garage should be its own zone with its own controls, separate from the house.
Need a licensed gas fitter for your hot water / boiler? Call CANRO at (604) 359-1081 — residential natural-gas heating and hot water across Metro Vancouver since 1999.
A hydronic unit heater contains a coil similar to a radiator, with a fan that pushes air across it to move heat into the space quickly, which suits a garage better than slow-radiating panel radiators because you often want the space to warm up in the time it takes to work in it, not overnight. The boiler still does the actual heating; the unit heater is just the delivery method for that zone.
Because a garage is usually physically separate from the main house, the piping run to reach it matters as much as the unit heater itself, and that run is often the weak point if it passes through an unheated crawl space or exterior wall on its way out.
Metro Vancouver doesn't see extreme cold for long stretches, but the occasional cold snap is exactly when an exterior-wall or attached-garage piping run is most at risk if the garage zone isn't running or the boiler is off. A freeze split in a garage supply line is a real risk on the coldest nights of the year, and it typically shows up as a leak discovered only once things thaw.
Options to manage this include keeping the garage zone on a low background setting through winter rather than fully off, insulating the exposed run well, or using a heat-traced section on the most exposed piping if the layout leaves no better option.
| Approach | Pros | Cons |
|---|---|---|
| Tied into house zoning | Simpler piping, one boiler covers both | Garage draws on the same boiler capacity as the house |
| Dedicated garage zone with own thermostat | Independent schedule, easy to leave garage cooler | Slightly more zoning hardware and control wiring |
| Separate small boiler for garage/shop only | Full independence from house heating | Higher upfront cost, a second appliance to maintain |
For most homeowners adding a single unit heater to an attached garage, tying into the existing boiler as its own zone is the practical middle ground, giving independent control without the cost of a second appliance.
A garage used mainly for vehicle storage with occasional use needs less capacity than a workshop where you're running power tools and standing for hours, and the unit heater's fan speed and coil size should reflect that. Ceiling height, door type (an insulated sectional door holds heat far better than an older single-panel door), and how often the door opens during use all affect real-world comfort more than the heater's rating alone.
A technician sizing a garage zone will also account for how much capacity the boiler already has allocated to the house, since an undersized boiler asked to cover both can end up short-cycling or struggling to keep up on the coldest days.
Garage air tends to carry more dust, and sometimes fumes from vehicles or stored chemicals, than living-space air, so the fan and coil on a garage unit heater need more frequent visual checks for dust buildup than an equivalent radiator inside the house. A dusty coil reduces heat transfer and makes the fan work harder for the same result.
Radiant and radiator loops share water (and often pressure) with a natural-gas boiler, so changes to the boiler's fill pressure, relief valve, or combustion venting are not homeowner work. That belongs to a Technical Safety BC licensed gas fitter. CANRO holds gas licence LGA0043870 and boiler licence LBP0046450. If you ever smell gas near the mechanical room, leave the house first and call FortisBC's emergency line, 1-800-663-9911, from outside.
Safety note
Radiant and radiator loops share water (and often pressure) with a natural-gas boiler, so changes to the boiler's fill pressure, relief valve, or combustion venting are not homeowner work. That belongs to a Technical Safety BC licensed gas fitter. CANRO holds gas licence LGA0043870 and boiler licence LBP0046450. If you ever smell gas near the mechanical room, leave the house first and call FortisBC's emergency line, 1-800-663-9911, from outside.
In many homes yes, usually as its own zone with a valve or small circulator, provided the boiler and piping run have enough capacity for the added load.
A frozen and split line typically isn't discovered until it thaws and leaks, which is why freeze protection for any exterior-wall or unheated-space run is planned in at installation rather than added after a failure.
For regular garage or workshop use, a properly sized hydronic unit heater tied to the boiler gives more even, hands-off heat than a portable heater, without extension cords or the need to remember to turn it off.
Yes, adequate clearance for airflow and any combustible materials stored nearby should be part of the installation plan, and a technician can confirm the right clearance for your specific unit and layout.
It adds some load, but a garage used occasionally and kept on a modest background setting typically adds far less than heating it the same as a living space full-time.
Family-run, TSBC-licensed (gas LGA0043870 · boiler LBP0046450), serving Metro Vancouver homes since 1999. Residential, natural gas only.
Call (604) 359-1081 Email info@canroheat.ca“Canro does an amazing job! Super professional and skilled with everything—boilers, furnaces, and AC. Always a pleasure working with them!”
“Five stars for Canro. We needed a replacement of a 30-year-old boiler. A new high-efficiency unit was installed—clean, professional work.”
“I can’t speak highly enough about George, who was recommended for a boiler service call for my parents’ home. George is excellent.”
25+ years keeping Metro Vancouver homes comfortable. Honest advice, upfront pricing, work that lasts.