6,000W on high gives an insulated two-car garage real headroom, the 3,000W low holds temperature cheaply, and it mounts to the ceiling or wall on a standard 30A circuit.
Read full review
~$176 typical price
Buy on AmazonUse-case guide · 2026
Best heater for a Garage
A garage is where 120V plug-in heaters fail: 1,500W is nowhere near enough for 400 square feet of concrete and an uninsulated door. Real garage heat is 240V electric (5,000–6,000W), natural gas or propane for big spaces, or a portable propane unit for short sessions — chosen by square footage, insulation, and what power you have out there.
What this space needs
Heater size needed
10 W/sq ft insulated · 15+ W/sq ft uninsulated (≈ 5,000W for a 2-car)
Type that fits best
240V fan-forced unit heater (or gas for 3-car / uninsulated)
- ▸Rule of thumb: a 450 sq ft insulated two-car garage wants ~4,500–5,000W (17,000 BTU); uninsulated, 7,000W+ — which is where a gas unit heater starts to make sense.
- ▸240V units need a dedicated 30A circuit. If the garage doesn't have one, budget a few hundred dollars for an electrician; it's still simpler than a gas line and vent.
- ▸Holding 45–50°F overnight on a thermostat protects paint, glue, and batteries cheaply; heating to 65°F all winter in an uninsulated garage is expensive.
Not sure what size you need? Run your room through the heater sizing tool →
Our picks
5,000W of hardwired ceiling-mount heat for about a hundred dollars — the cheapest permanent garage heater that actually works.
Read full review
~$108 typical price
Buy on Amazon
50,000 BTU from natural gas or propane, vented, on a wall thermostat — three times an electric unit's output at roughly a third the running cost.
Read full review
~$453 typical price
Buy on Amazon
Propane, no electricity, 9,000 BTU in seconds. For a couple of hours on a Saturday with the door cracked and a CO alarm running, it's the cheapest garage heat there is.
Read full review
~$100 typical price
Buy on AmazonBefore you buy
- ▸Hardwired 240V heaters are an electrician's job; a heater on undersized wiring is a fire.
- ▸Propane heaters indoors need ventilation and a battery CO alarm every time — no exceptions, no matter what the box says.
- ▸Mount fan-forced units in a corner, 7–8 ft up, angled down across the floor toward the far wall.
- ▸Insulating the garage door and sealing the bottom gap often does more than the next size up in heater.
Frequently asked questions
What size heater do I need for a two-car garage?
Roughly 10 watts per square foot if insulated — about 4,500–5,000W (15,000–17,000 BTU) for a 450 sq ft garage. Uninsulated, plan on 15–20 W/sq ft, which is 7,000W+ and usually points to a gas unit heater.
Can I use a 120V plug-in heater in a garage?
It'll warm a workbench area if you stand in front of it, but 1,500W (5,100 BTU) can't raise the temperature of a garage meaningfully. For real garage heat you need a 240V electric unit or a gas heater.