Garage, shed and workshop heaters: what to buy and what it costs
How to heat a garage, shed or workshop for less: the heaters that work in cold, uninsulated spaces and what they cost per hour at the Ofgem price cap.
How to heat a garage without wasting money
Most garages and sheds are uninsulated: the heat escapes almost as fast as you make it. So don't try to keep them warm all day. Warm the space and yourself only while you work in it, with a powerful fan heater, and switch it off when you leave.
| Heater | Per hour | 2 hours, 3 times a week, a month |
|---|---|---|
| 3 kW fan heater, full power | 79.0p | £20.53 |
| 3 kW heater on its 1.5 kW setting | 39.5p | £10.26 |
| Desiccant dehumidifier (keeps tools dry) | 17.1p | £8.90 4 hours, 3 times a week |
At the Ofgem price cap (26.32p/kWh). Desiccant figure is typical; check the label on yours.
Garage and workshop heaters we recommend
Dimplex DXFF30TSN 3kW Fan Heater
- Fan heater · 3,000 W
- A 3 kW flat fan heater from Dimplex with two heat settings, a thermostat with frost setting and a cool-blow option: lots of heat fast for a garage, workshop or large cold room.
- Costs 79.0p an hour at full power.
Dimplex RUG3TS Rugged Workshop 3kW Fan Heater
- Fan heater · 3,000 W
- Steel-cased 3 kW workshop heater (1.5 or 3 kW) with thermostat and frost setting, tilt switch, dust filter and IP21 drip protection: built for garages and workshops, not living rooms.
- Costs 79.0p an hour at full power.
Pro Breeze 10L Desiccant Dehumidifier
- Dehumidifier
- Desiccant dehumidifier that keeps working in cold spaces (garages, basements, unheated rooms), with timer, air filter and continuous drainage.
- Costs 17.1p an hour (typical) at full power.
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Make every kWh count
- Draught-proof the door: a brush strip along the bottom of an up-and-over door makes a big difference.
- Insulate what you can: even foil-backed insulation on the door and roof panels holds the heat longer.
- Point the heater at you, not at the far wall: a fan heater warms the person in front of it first.
- Damp, not cold, rusts tools: a desiccant dehumidifier keeps working in an unheated garage where a compressor one struggles.
Safety in garages and sheds
- Keep heaters away from sawdust, paint, fuel and solvents.
- Use a heater with a tilt switch and overheat protection; fully unwind any cable reel before using it with a heater.
- Never use gas or paraffin heaters in a closed space without ventilation: they produce carbon monoxide and moisture.
Frequently asked questions
What is the cheapest way to heat a garage?
Heat it only while you are in it, with a fan heater pointed at you: 79.0p an hour for 3 kW at full power. Trying to keep an uninsulated garage warm all day wastes most of the heat.
Can I leave a heater on in my garage to stop things freezing?
Some heaters have a frost setting that switches on only near freezing. Use it with a heater designed for long periods and away from anything flammable; insulation helps more than heat.
What size heater do I need for a garage?
Uninsulated single garages usually need about 3 kW to feel warm while you work. For an insulated workshop, 2 kW is often enough.
Running costs use the Ofgem energy price cap, 1 October to 31 December 2026: average unit rate for electricity paid by Direct Debit (26.32p/kWh, standing charge 54.83p/day) and gas (7.97p/kWh). National averages; your region and tariff may differ. Prices on Amazon change: check the live price before you buy.