What's inside
- Quick comparison of 240 volt garage heaters
- Why choose 240 volts for a garage heater
- Best plug-in: Dr. Infrared DR-988
- Best for larger spaces: Dr. Infrared DR-975 class
- Best ceiling-mount: Fahrenheat FUH series
- Gas alternative: Mr. Heater Big Maxx
- Worked example: sizing and circuit
- How to choose a 240 volt garage heater
- Cost to run
- Frequently Asked Questions
- Quick comparison of 240 volt garage heaters
- Why choose 240 volts for a garage heater
- Best plug-in: Dr. Infrared DR-988
- Best for larger spaces: Dr. Infrared DR-975 class
- Best ceiling-mount: Fahrenheat FUH series
- Gas alternative: Mr. Heater Big Maxx
- Worked example: sizing and circuit
- How to choose a 240 volt garage heater
- Cost to run
- Frequently Asked Questions
As an Amazon Associate I earn from qualifying purchases. This post may contain affiliate links at no extra cost to you.
The best 240 volt garage heaters deliver 4,800 to 7,500 watts, roughly 16,000 to 25,000 BTU per hour, which is enough to warm a one-car to two-car insulated garage. The Dr. Infrared DR-988, a 5,600 watt portable unit on a 30-amp 240 volt outlet, is the common plug-in pick; hardwired ceiling units such as the Fahrenheat FUH series and the Dr. Infrared DR-975 are the choices if you want the heater off the floor. This guide compares real current options, shows how to size one to your garage, and explains the circuit work that decides whether you can install it.
As an Amazon Associate we earn from qualifying purchases at no extra cost to you.
Sections
- Quick comparison of 240 volt garage heaters
- Why choose 240 volts for a garage heater
- Best plug-in: Dr. Infrared DR-988
- Best for larger spaces: Dr. Infrared DR-975 class
- Best ceiling-mount: Fahrenheat FUH series
- Gas alternative: Mr. Heater Big Maxx
- Worked example: sizing and circuit
- How to choose a 240 volt garage heater
- Cost to run
- Frequently Asked Questions
Our Top Picks
Quick comparison of 240 volt garage heaters
| Pick | Best for | Power | Heat output | Rated coverage | Installation | Price range |
|---|---|---|---|---|---|---|
| Dr. Infrared DR-988 | Best plug-in 240 V heater | 5,600 W, 240 V | About 19,100 BTU/hr | Up to about 600 sq ft, moderate insulation (listing figure) | NEMA 6-30R outlet, 30 A circuit, wall or ceiling mount | Mid-range |
| Dr. Infrared DR-975 class | Best for larger hardwired space | 4,700 / 7,500 W | About 16,000 / 25,600 BTU/hr | Larger garages | Hardwired | Mid-range to upper-mid |
| Fahrenheat FUH series (FUH54 class) | Best ceiling-mount fan-forced | 2,500 / 5,000 W, 208 or 240 V | Up to about 17,000 BTU/hr | Up to about 500 sq ft insulated | Hardwired, ceiling or wall | Mid-range |
| Mr. Heater Big Maxx (gas alternative) | Best if no 240 V and you have a gas line | Propane or natural gas | Up to 80,000 BTU/hr | Up to about 2,000 sq ft class | Gas line, venting, 24 V thermostat | Upper-mid |
Specifications follow the manufacturer listings and common retailer pages. Coverage claims vary widely by insulation, ceiling height, and climate, so treat them as ceilings, not guarantees.
Why choose 240 volts for a garage heater
Power equals volts times amps. At 120 volts, a 15-amp outlet tops out at 1,800 watts. At 240 volts, a 30-amp circuit supplies up to 7,200 watts, and the heater needs half the current for the same wattage. That is why serious garage heaters are 240 volt: they can deliver the wattage needed for a 400 to 600 square foot space without overloading household wiring. It also means they require an electrician-installed circuit if you do not already have one.
Best plug-in: Dr. Infrared DR-988
The DR-988 is a 5,600 watt industrial-style heater that comes with a 6-foot cord and a NEMA 6-30P plug. It needs a dedicated 30-amp, 240 volt outlet (NEMA 6-30R). Thermostat range is listed as 37 to 113 degrees Fahrenheit on some listings and 45 to 95 on others, so check the product label. It weighs about 17 to 21 pounds depending on the listing and mounts on a wall or ceiling or sits on its bracket. At 5,600 watts it produces about 19,100 BTU per hour, which the brand says suits a garage up to about 600 square feet with moderate insulation. The related DR-988A is rated for 208 or 240 volt with 4,800 or 5,600 watts. Because it plugs in, a competent electrician can install the outlet and you can take the heater with you if you move.
Trade-offs: the fan is audible, the plug-in requires the specialty outlet, and a 600 square foot claim assumes decent insulation. In an uninsulated two-car garage in a hard winter it will warm the space, but not to living-room temperature.
Best for larger spaces: Dr. Infrared DR-975 class
The DR-975 is a hardwired 240 volt heater with two power settings, 4,700 and 7,500 watts according to listings. At the high setting it makes about 25,600 BTU per hour. Hardwiring means a fixed installation and a larger breaker, typically 40 amps for 7,500 watts, which is a matter for an electrician. It is a better fit for a long or tall shop, or for a space with poor insulation.
Best ceiling-mount: Fahrenheat FUH series
Fahrenheat’s FUH garage heaters are ceiling- or wall-mounted forced-air heaters, rated for 208 or 240 volts, and the FUH54 class offers 2,500 or 5,000 watts, up to about 17,065 BTU per hour and coverage of up to roughly 500 square feet insulated. Mounting overhead keeps the floor clear in a shop. Because it is hardwired with a thermostat, it behaves more like a permanent appliance. The 2,500 watt setting is useful for holding temperature once the space is warm.
Gas alternative: Mr. Heater Big Maxx
If a 240 volt circuit is not an option and you have natural gas or propane, a ceiling-mounted gas unit like the Mr. Heater Big Maxx (about 50,000 to 80,000 BTU per hour) delivers far more heat per dollar of installation. It requires gas piping, venting, a 24 volt thermostat, and a licensed installer. It is the better choice for a large or leaky garage.
Worked example: sizing and circuit
Take a 22-by-24 foot garage (528 square feet) with an 8-foot ceiling. The volume is 4,224 cubic feet. For a well-insulated garage, a common rule is about 10 watts per square foot, which gives 5,280 watts. A 5,600 watt heater fits. For a poorly insulated garage at 15 to 20 watts per square foot, you need 7,900 to 10,500 watts, which points to the 7,500 watt unit plus insulation upgrades, or to gas.
Now the circuit. Amps equal watts divided by volts. A 5,600 watt heater at 240 volts draws 23.3 amps. Heaters are continuous loads, so the breaker must be rated at 125 percent of that, about 29 amps, which rounds up to a 30-amp breaker with 10-gauge copper wire. A 7,500 watt heater draws 31.3 amps, so it needs a 40-amp breaker and 8-gauge wire. A 4,800 watt heater at 20 amps needs a 25-amp or 30-amp breaker. Wire gauge depends on distance and local code, so confirm with a licensed electrician.
One more detail: running a 240 volt heater on a 208 volt supply, common in some commercial buildings, cuts output. Power falls with the square of the voltage ratio, so 5,600 watts at 240 volts becomes about 4,200 watts at 208 volts.
How to choose a 240 volt garage heater
Start with square footage and insulation
Use 10 watts per square foot for insulated, 15 to 20 for poorly insulated. Round up to the nearest model, and consider a two-stage heater for flexibility.
Plug-in or hardwired
Plug-in saves installation cost and lets you move the heater. Hardwired gives higher wattage options and a cleaner installation. Both require a licensed electrician if you need a new circuit.
Mounting height
Ceiling mounting puts the heater above the work. Check the manufacturer’s clearance distances to combustible materials and keep stacks of lumber clear.
Thermostat and fan
A built-in thermostat is convenient, but a wall thermostat gives more accurate control. A quiet fan matters if you spend long hours in the shop.
Dust and safety
Woodworking dust accumulates on heater elements and intakes. Vacuum them regularly, keep finishing materials away, and install smoke and carbon monoxide detectors in the garage.
Cost to run
A 5,600 watt heater uses 5.6 kilowatt-hours per hour at full output. At 16 cents per kilowatt-hour, that is about 90 cents an hour. If the thermostat cycles the heater on half the time, the cost is closer to 45 cents. Compare that with your gas rate if you are choosing between electric and gas.
Frequently Asked Questions
What size 240 volt heater do I need for a two-car garage?
A well-insulated two-car garage of about 500 square feet needs roughly 5,000 to 6,000 watts, so the DR-988 class fits. If the garage is uninsulated or in a cold climate, plan for 7,500 watts or more, or add insulation.
What outlet does a 5,600 watt 240 volt heater need?
The DR-988 uses a NEMA 6-30 plug, which means a 30-amp, 240 volt receptacle on a dedicated circuit. Have a licensed electrician install it.
Are 240 volt electric heaters more efficient than gas?
Electric resistance heaters convert nearly all electricity to heat, so they are efficient at the point of use. Cost per unit of heat depends on local electricity and gas prices, and gas is often cheaper to run in many areas.
Can I run a 240 volt heater on 208 volts?
Many can, but output drops. A 5,600 watt unit delivers around 4,200 watts at 208 volts. Choose a model rated for 208 or 240 volts if your supply is 208.
Is it safe to run a heater in a shop with sawdust?
It can be safe with precautions. Keep sawdust cleaned from the heater, maintain clearance from combustibles, and use a heater with overheat protection.