This is the decision that trips up most garage-heater buyers, and the honest answer is that it comes down to two things: whether you can run a 240V circuit, and whether your garage is attached to your house. Get those two facts straight and the choice mostly makes itself. Here's the full breakdown.
- Your garage is attached to the house
- You want set-and-forget heat with no fumes
- You can run (or already have) a 240V circuit
- You'd rather not deal with refilling tanks
- Your shop is large or detached
- You only need heat occasionally, fast
- You don't have the electrical capacity for big electric heat
- You can ventilate the space properly
Compared on what matters
1. Running cost
This is where it gets situational, because the winner depends entirely on your local electricity and propane prices. The fair way to compare is cost per unit of heat. Electric resistance heat turns essentially all the energy into heat in the room. Portable propane heaters vent indoors, so almost all their heat stays in the space too — that's exactly why they need ventilation.
Here's an illustrative comparison at example rates — plug in your own to see which way it tips:
| Fuel | Example rate | Cost per 100,000 BTU |
|---|---|---|
| Electric | $0.16 / kWh | ≈ $4.70 |
| Propane | $3.00 / gallon | ≈ $3.30 |
| Natural gas | $1.20 / therm | ≈ $1.20 |
At those example rates propane edges out electric, and natural gas beats both by a wide margin. But electricity prices vary enormously by region — in some areas the gap narrows or flips. The takeaway: propane usually wins on cost-per-BTU for big spaces, natural gas wins overall if you have a line, and electric's premium buys you convenience and zero ventilation hassle.
2. Installation & convenience
This is propane's home-field advantage and electric's biggest catch.
Propane: plug-and-play
Screw on a tank, click the igniter, done. No wiring, no electrician, fully portable between spaces. The ongoing cost is convenience: you refill tanks, and you can run out mid-job.
Electric: depends on the size
A small 120V plug-in is the easiest thing in the world. But any electric heater big enough for a real garage needs a dedicated 240V circuit — frequently a licensed-electrician job that can cost a few hundred dollars up front. Once it's in, though, there's nothing to refill and nothing to think about.
Already decided? See our top picks for each type → Electric & propane, sorted by garage size3. Heat output & speed
Propane wins on raw, fast heat. A portable propane forced-air unit can throw 60,000+ BTU and warm a cold shop in minutes — useful when you only fire it up for an hour of work. Electric units, especially within a single 240V circuit's limits, heat more gradually and top out lower, which suits keeping an attached garage steadily warm rather than blasting a cold one fast.
4. Ventilation, moisture & safety
Electric heat produces neither — no fumes, no added moisture, safe to run unattended in a sealed space. For an attached garage that shares air with your house, that safety margin is usually reason enough to choose electric outright.
5. So which one for your garage?
- Attached garage: Electric, almost always. The shared air with your living space makes the no-fumes, no-CO argument hard to beat.
- Detached shop you heat occasionally: Propane. Fast heat, no wiring, and ventilation is easier in a standalone building.
- Large space used year-round with a gas line: A mounted natural-gas unit — cheapest to run long term.
- Small, tight single bay: A 120V electric plug-in. Cheap, simple, no install.
Frequently asked questions
- Is propane or electric cheaper for a garage?
- Propane is usually cheaper per unit of heat for larger spaces, while electric costs more to run but saves you the up-front wiring and the ongoing tank refills. Natural gas, if you have a line, is typically cheapest of all.
- Is it safe to run a propane heater in a closed garage?
- Not without ventilation. Propane heaters produce carbon monoxide and should only be used with fresh-air ventilation and a working CO detector. For a fully sealed or attached space, electric is the safer choice.
- Do propane heaters make a garage damp?
- They can. Burning propane releases water vapor, which can raise humidity in a closed garage and contribute to rust on tools and bare metal. Electric heaters don't add moisture.
- Can I avoid hiring an electrician?
- Only if a 120V plug-in (max ~1,500 watts) is enough for your space, or if you go propane. Larger electric heaters need a 240V circuit, which usually means an electrician.