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Published August 3, 2026. Updated October 10, 2026.
Propane and kerosene heaters burn fuel and produce carbon monoxide, so proper ventilation is essential any time you run one in a garage or other enclosed space. Always follow the manufacturer’s instructions, install a working carbon monoxide detector near the space, and check your local fire and building code before operating a fuel-burning heater indoors.
For most uninsulated garages, a portable propane heater like the Mr. Heater Big Buddy delivers the best mix of low upfront cost and low cost per hour of heat. That assumes the space is properly ventilated. A hardwired electric garage heater is the better call if you already have a 240-volt circuit. It gives you thermostat-controlled, hands-off warmth with no combustion byproducts. A high-output kerosene forced-air heater makes the most sense for a large, drafty detached garage or barn that needs to go from freezing to workable fast. There is no single best garage heater. The right pick depends on your space’s size, your electrical setup, and how often you’ll run it.
I’ve spent years camping and boating, and fuel-burning heat has taught me one rule. Ventilation and a working carbon monoxide detector matter more than the BTU number on the box.
Which garage heater is best?
- Large garages: Dyna-Glo Delux KFA80DGD (kerosene). At 80,000 BTU/hr and coverage up to 1,900 sq ft, it’s the heater that can warm a large, uninsulated detached garage.
- Budget pick: Mr. Heater Big Buddy MH18B (propane). It costs $121.80, needs no installation, and has a built-in low-oxygen shutoff sensor, for a smaller garage you heat occasionally.
- Upgrade pick: Dr. Infrared DR-910F (electric, 240V). It’s thermostat-controlled with zero combustion byproducts, and it’s the right pick if you already have the electrical service for a permanent workshop heater.
Garage heater comparison: propane vs. electric vs. kerosene
| Heater | Price | BTU Output | Coverage Area | Fuel Cost Profile | Safety Features |
|---|---|---|---|---|---|
| Mr. Heater Big Buddy MH18B (propane) | $121.80 | 4,000–18,000 BTU/hr | Up to 450 sq ft | ~$0.53/hr at max output (propane, $2.67/gal) | Low-oxygen shutoff sensor, tip-over safety switch |
| Dr. Infrared DR-910F (electric) | $599.99 | 30,000 BTU/hr (10,000W, 240V) | Up to 700 sq ft | ~$1.84/hr at max output (electricity, $0.1844/kWh) | UL & cUL listed, thermally protected enclosed motor, remote thermostat |
| Dyna-Glo Delux KFA80DGD (kerosene) | $229.99 | 80,000 BTU/hr | Up to 1,900 sq ft | ~$3.20/hr at max output (kerosene, ~$5.40/gal) | Flame-out sensor, overheat auto shut-off valve, CSA certified |
How do you choose a garage heater for an uninsulated space?
An uninsulated garage or workshop behaves nothing like a bedroom or a den. So the specs that matter for a small indoor space heater don’t translate directly here. Heat leaks out through an uninsulated garage door, gaps around windows, and often a shared wall with the outdoors on two or three sides. That means the coverage-area number on the box assumes far less heat loss than your garage will have. Before comparing BTU output, walk your space and note three things. Measure the square footage. Check how tight the garage door seals. Find out whether you have (or can add) a 240-volt outlet.
Fuel-burning heaters (propane and kerosene) generally deliver more heat per dollar of upfront cost. They’re also easier to move between a garage and a job site. But they need real airflow and a carbon monoxide detector nearby. Electric heaters cost more to buy and more per unit of heat. They don’t produce combustion byproducts or need refueling, though. With a thermostat doing the work, they can run unattended. If your garage is attached to your house and shares a wall or ductwork with living space, that alone is a strong argument for electric. Propane and kerosene aren’t unsafe when used correctly. The ventilation requirements are just harder to guarantee in an attached structure.
If your garage doubles as a spot to run a backup generator during outages, read our comparison of portable generators. The same ventilation logic applies there too.
Is the Mr. Heater Big Buddy a good garage heater for small spaces?
The Big Buddy MH18B is a portable radiant propane heater with three settings spanning 4,000 to 18,000 BTU per hour, priced at $121.80. Rated for roughly 450 sq ft of coverage, it runs on two 1-lb propane cylinders that thread directly into the unit. You can also run it on a 20-lb tank with a separate hose and filter accessory. A built-in low-oxygen shutoff sensor cuts the heater off if oxygen levels drop too low. An accidental tip-over shutoff rounds out the safety features. Mr. Heater’s own spec table lists no high-limit overheat shutoff on this model.
What are the downsides of the Big Buddy MH18B?
- Pros: It has the lowest upfront price of the three. It’s indoor-rated with a low-oxygen shutoff sensor and tip-over switch. Installation isn’t required. Per the cost table below, it’s also the cheapest of the three to run per hour.
- Cons: The 450 sq ft rated coverage is undersized for a large detached garage or a two-car workshop. 1-lb cylinders run out quickly on the high setting unless you add a hose adapter for a 20-lb tank. Radiant heat warms what’s in front of it rather than the whole room evenly.
Standout call: for a one-car garage or a workbench corner you’re heating for an hour or two at a time, this is the heater to buy, full stop. Named dealbreaker: if your garage runs larger than roughly 450 sq ft, step up to the kerosene heater. If it has limited airflow, go electric instead.
Is the Dr. Infrared DR-910F worth it as a workshop heater?
The DR-910F is a hardwired 240-volt electric heater rated at 10,000 watts. The manufacturer lists its output at 30,000 BTU per hour, with coverage up to 700 sq ft. It lists for $599.99 and mounts to a wall or ceiling bracket. A remote-controlled thermostat with a 50 to 85°F range lets it hold a set temperature on its own. It’s UL and cUL listed, and the manual calls for 6 AWG copper wiring on the circuit.
Because it’s resistive electric heat, there’s no flame, no fuel to store, and no carbon monoxide to worry about. That matters if your garage shares a wall or ductwork with the house. The tradeoff is cost. It’s the most expensive heater here to buy. The $599.99 sticker doesn’t include the electrician’s bill if you don’t already have a spare 240-volt circuit near the garage.
What are the downsides of the DR-910F?
- Pros: There’s no combustion, no fuel to buy or store, and no carbon monoxide risk. The thermostat holds a set temperature automatically. It covers up to 700 sq ft, more than the Big Buddy’s 450. It’s UL and cUL listed.
- Cons: It has the highest upfront cost, before any electrical work. It’s permanently wall- or ceiling-mounted, so you can’t move it between the garage and a job site. Per the cost table below, it’s also the most expensive to run per unit of heat delivered.
Standout call: this is the heater for someone who treats their garage as a daily workshop and wants to set a temperature and forget it, not for occasional weekend warm-ups. Named dealbreaker: if you don’t already have a 240-volt circuit in the garage, budget for an electrician on top of the sticker price. Otherwise this pick stops being an upgrade and turns into a bigger electrical project than the heater itself.
Is the Dyna-Glo KFA80DGD the best garage heater for large spaces?
The KFA80DGD is a portable forced-air kerosene heater rated at 80,000 BTU per hour with coverage up to 1,900 sq ft. Dyna-Glo prices it at $229.99. It holds 5 gallons of fuel, with roughly 9 hours of runtime on a full tank. Built to run on 1K kerosene as well as #1/#2 diesel, fuel oil, Jet-A, or JP-8, it’s useful if kerosene isn’t easy to find locally. Safety features include an integrated flame-out sensor, an overheat auto shut-off valve, and CSA certification. A built-in thermostat and fuel gauge are included.
What are the downsides of the Dyna-Glo KFA80DGD?
- Pros: It has the highest raw BTU output of the three by a wide margin. Its rated coverage reaches up to 1,900 sq ft, built for big, drafty spaces. The flame-out sensor and overheat shutoff are standard. It runs on several fuel types.
- Cons: Strong fuel odor and combustion byproducts make it a poor fit for a garage attached to living space. The forced-air fan is loud, so it’s not a background heater. Hand-refueling from a stored fuel container is required rather than a piped supply. Per the cost table below, it has the highest per-hour running cost of the three, despite the biggest BTU number.
Standout call: for a large, detached, uninsulated garage or barn that needs to go from cold to workable fast, this is the most decisive pick on this list. Nothing else here puts out this much heat. Named dealbreaker: don’t run this in a garage attached to your house or sharing air with living space. The odor and ventilation demands are real, and we’re naming that plainly rather than splitting the difference between products.
Garages also tend to run damp as well as cold, especially once a fuel-burning heater is adding moisture from combustion. If that’s a recurring issue in your space, a standalone dehumidifier is worth budgeting for alongside whichever heater you pick.
How much does each garage heater cost to run?
BTU ratings tell you how much heat a unit can put out, not what that heat costs. The tables below start from each heater’s manufacturer-rated maximum output. They apply named, current fuel prices and standard energy-content figures for each fuel. It’s the same kind of math a utility or fuel supplier would use to estimate your bill, applied heater by heater instead of home by home.
Which fuel prices and energy content did we use?
| Fuel | Price Used | Source | Energy Content |
|---|---|---|---|
| Propane | $2.67/gal | EIA residential propane price survey, week ending March 30, 2026 (EIA pauses weekly publication April–September) | 91,420 BTU/gal (U.S. DOE Alternative Fuels Data Center, higher heating value) |
| Electricity | $0.1844/kWh (18.44¢) | EIA Electric Power Monthly, U.S. average residential price, May 2026 | 3,412 BTU per kWh; resistive heat delivers all of it, so 10 kWh = about 34,120 BTU |
| Kerosene | ~$5.40/gal | Average of current K-1 kerosene retail supplier pricing ($5.20–$5.69/gal), Northeast markets (gethomeheat.com, accessed August 2026). Regional proxy, since national kerosene retail data is published far less consistently than propane or electricity | 135,000 BTU/gal (EIA thermal conversion factor: 5.670 million BTU per 42-gallon barrel) |
What does each garage heater cost per hour?
| Heater | Fuel Burned per Hour at Max Output | Cost per Hour at Max Output | Cost per 10,000 BTU Delivered | Cost for an 8-Hour Overnight Run |
|---|---|---|---|---|
| Mr. Heater Big Buddy MH18B (18,000 BTU/hr, propane) | ~0.20 gal propane | $0.53 | $0.29 | $4.21 |
| Dr. Infrared DR-910F (10,000W, electric) | 10 kWh | $1.84 | $0.54 | $14.75 |
| Dyna-Glo Delux KFA80DGD (80,000 BTU/hr, kerosene) | ~0.59 gal kerosene | $3.20 | $0.40 | $25.61 (≈ one full 5-gal tank) |
Two things stand out. First, propane is the cheapest fuel per unit of heat delivered in this comparison, even though the Big Buddy has the smallest BTU rating of the three. A smaller flame burning a cheaper fuel can still win on cost per 10,000 BTU. Second, the kerosene heater’s 5-gallon tank and roughly 9-hour runtime line up almost exactly with an 8-hour overnight burn at full output. That’s a useful gut check if you’re planning to run one through a cold night in the shop. These figures assume continuous operation at each heater’s maximum rated output. A thermostat-controlled unit like the DR-910F, or a Big Buddy on its low or medium setting, will typically cost less per hour in real use.
Specs come from manufacturer-published specifications and current retail listings, cross-checked across multiple retailer and manufacturer pages for each model. Fuel prices come from the named sources above. Our full process for sourcing specs, pricing, and safety information is explained on our editorial standards page.
Questions about choosing a garage heater
Is it safe to run a propane or kerosene heater in a closed garage?
Fuel-burning heaters need fresh-air ventilation to run safely, so closed is the problem, not the fuel type itself. Crack a window or the garage door. Follow the clearance and ventilation instructions in the manufacturer’s manual. Install a carbon monoxide detector in the space any time a propane or kerosene heater is running.
What size garage heater do I need for an uninsulated space?
Match the heater’s rated coverage area to your garage’s square footage, then round up rather than down. Uninsulated walls and a standard garage door lose heat much faster than an insulated room of the same size. In this comparison, that’s roughly 450 sq ft for the Big Buddy MH18B, 700 sq ft for the DR-910F, and up to 1,900 sq ft for the KFA80DGD, per each manufacturer’s rating.
Do I need a 240-volt circuit for an electric garage heater?
Yes, for the Dr. Infrared DR-910F. It’s a hardwired 240-volt unit rated at 10,000 watts, and its manual specifies 6 AWG copper wiring for the circuit. If your garage only has standard 120-volt outlets, factor in the cost of adding a 240-volt circuit. Do that before comparing its price to a portable propane or kerosene heater.
Can a kerosene heater run all night in a garage?
Only if you follow the manufacturer’s instructions on ventilation, clearance, and unattended operation. You also need working carbon monoxide detection in place. Check the specific model’s manual before leaving any fuel-burning heater running unattended or overnight. The Dyna-Glo Delux KFA80DGD’s 5-gallon tank holds roughly 9 hours of fuel at full output, which is close to a typical overnight run.
Which fuel is cheapest for a garage heater?
Based on our cost-per-10,000-BTU calculation, propane came out cheapest per unit of heat delivered. Kerosene was in the middle, and electricity was the most expensive per BTU. Electricity has no fuel to buy or store and produces no combustion byproducts, though, which has its own value.
Do I need a carbon monoxide detector with a low-oxygen shutoff?
Yes. A low-oxygen shutoff sensor, like the one built into the Mr. Heater Big Buddy, is a safety feature on the appliance. It’s not a substitute for a separate carbon monoxide detector in the space. Follow the manufacturer’s instructions and your local code for both.
If fuel-cost math like this is useful to you, our wood vs. propane vs. smokeless fire pit comparison runs a similar cost breakdown for outdoor propane use. You can also browse every comparison in this space in our Heating & Cooling category.
Prices are approximate, current as of publication, and change frequently — confirm the latest price with the retailer before buying.
