Propane heaters for a garage

A vented propane unit heater on a bulk tank runs about $0.80/hr flat out at Illinois prices; a portable Buddy-type radiant heater on 1-lb cylinders costs more per hour to run ($1.04/hr) and is built for attended spot heat only — never a whole-garage, set-and-forget system. This page sells the vented class; the portable class gets a safety verdict, not a buy button.

"Propane heater for a garage" covers two unrelated tools. A vented unit heater bolts to the wall or ceiling, burns off a natural gas line or a bulk propane tank, and exhausts outdoors through its own flue — it's the class this page sells. A Buddy-type portable radiant heater burns unvented, indoors, on small disposable cylinders — it has a real, narrow use, and it never gets a buy link on any BayHeat page, attached garage or detached.

Vented unit heaters: the class this page sells

A vented natural gas or propane unit heater covers a whole garage from one wall-mounted unit. On a gas line, see the natural gas garage heater page for sizing and venting. Code sets a floor for where its burner can sit: Ignition source at least 18 in above the garage floor for fuel-fired appliancesRA code or reference citationInternational Fuel Gas Code, 2021 · checked 2026-09-25Report a problem. Both units below need a licensed gas fitter for the connection and the permit — this isn't a DIY hookup.

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What it takes to run one, per BayHeat's own verdict tool

• Installed and permitted by a licensed gas fitter -- this isn't a DIY connection. (BayHeat)
• Burner at least 18 in above the garage floor, and at least 6 ft up or guarded against vehicle impact. (IFGC 305.3 / 305.5, IFGC 2021)
• Put a UL 2034 CO alarm in the house outside each sleeping area (code, for new homes and permitted work). BayHeat also advises one by the garage door, and a low-level CO monitor in the garage rated for its temperature range while this heater runs. (IRC R315 (house alarm); BayHeat (garage door and monitor), IRC 2021)

Cost per hour and per season, computed at Illinois prices

Bulk propane through a vented 80%-efficient unit heater costs about $28/MMBtu delivered (2026-03-30 price); the same garage's season comes to roughly $1,387/season. Cylinder-exchange propane through a 92%-efficient Buddy-type unit costs about $36/MMBtu delivered — the exchange premium over bulk propane outweighs the Buddy's efficiency edge. Neither figure includes install cost; the calculator runs both against your own garage and state.

Why not a Buddy heater here

The Mr. Heater Buddy, 4,000-9,000 BTU/h portable propane heater and Mr. Heater Big Buddy, 4,000-18,000 BTU/h portable propane heater are real, listed products with a real use — a stalled car, a job site trailer, a detached shed with no power run yet. Their own manuals scope that use narrowly, and BayHeat's Can I run it? tool quotes it rather than soften it:

Manual: for recreational and emergency indoor use. Never leave it unattended while it burns. A 20-lb refillable cylinder can only feed this heater from outdoors, on the maker's own hose and fuel filter — never stored or used inside the garage, attached or detached. That manual scope is why this class carries no buy button on this page: it's a real product for a narrow job, not a whole-garage heating system to shop for here. Run your own situation through Can I run it? before you buy one anywhere.

Don't buy a torpedo heater either

A forced-air "torpedo" propane heater is excluded from every BayHeat recommendation for any enclosed garage, full stop — stricter than some of those heaters' own manuals. Use the vented unit heater above, an electric class, or a mini-split instead. The shop heater guide applies the same rule to a workshop.

Safety scope

Next step

Check my heater and garage → for a verdict specific to your circuit, cylinder and what's stored where, or compare every fuel at your own state's prices.