Shed Heater Guide: Best Ways to Heat a Shed or Workshop

Winter in Perth is short, but it’s wet and cold enough to turn an uninsulated shed into a space you avoid rather than use. July temperatures average around 13.5°C, and a bare steel structure holds almost none of that warmth on its own.

Without a plan, heating a shed becomes trial and error. A heater that’s too small runs constantly and barely takes the edge off. One that’s the wrong type in a sealed space brings a real carbon monoxide risk. Either way, you end up paying for heat that isn’t doing its job.

This guide walks through exactly how to heat a shed in winter, from insulating it properly through to choosing and sizing the right shed heater safely. You’ll also find real Australian running-cost comparisons and answers to the questions Perth shed owners ask most.

Here’s Everything You Need to Know in Under a Minute

Table of Contents

How to Heat a Shed in Winter

To heat a shed in winter effectively, insulate and seal it first to stop warmth escaping, then match a heater to whether your shed has mains power connected.

Step 1: Insulate and Seal Your Shed First

Heating an uninsulated shed is like heating with the door open. Warmth escapes through bare steel walls and roof sheeting almost as fast as a heater produces it, so insulation comes before any heater purchase.

At minimum, insulate the roof and walls with reflective foil or batts, and cover a bare concrete or timber floor with rubber matting or plywood. Seal gaps around roller doors, PA doors and windows with weather stripping so draughts aren’t undoing the work.

For the full specification, our winterising a shed guide covers roof, wall and floor insulation step by step, and insulating a shed properly breaks down which materials suit steel-frame builds. Get this right first and every heater on this list works harder for less power.

Step 2: Choose a Heating Method That Suits Your Setup

Your heating options come down to one thing first: does your shed have power? If it’s wired for electricity, an oil-filled column heater or a ceramic panel heater with a plug-in thermostat gives steady, low-maintenance warmth. A fan heater will heat a shed faster in the short term, but running one for hours at a time dries out the air and carries a higher fire risk than the alternatives.

Without mains power, portable LPG blue-flame heaters, paraffin heaters, or a diesel heater running off a 12V battery or small solar setup are the practical alternatives. Each needs the ventilation rules covered in Step 3 below.

If your shed currently has no power at all, weigh up the cost of running new circuits against the cost of an off-grid heater. A licensed electrician running a dedicated circuit is a one-off cost that also opens up lighting, tools and power points, which usually pays off faster than repeatedly buying gas bottles or diesel over several winters.

Scale matters too. Sheds Perth offers a shed builder tool to help you plan scale before you commit, and Action Sheds builds everything from small residential garages through to industrial sheds and commercial sheds for Perth businesses. A 6m x 6m residential workshop heats comfortably with one or two electric units. A large industrial shed generally needs a dedicated heating system rather than portable heaters, so match your approach to the actual structure.

Step 3: Follow Strict Heater Safety Rules

Any heater that burns fuel produces carbon monoxide, an odourless gas that builds up quickly in a sealed shed. Health authorities are clear that outdoor gas appliances, including patio heaters, should never be brought indoors, and every combustion heater needs a dedicated carbon monoxide detector plus active ventilation while it’s running.

If your shed doesn’t already have roof ventilation, that’s worth fixing before you introduce any heater. See why roof ventilation matters for the options available. Keep a window, door or vent open the entire time a gas, diesel or paraffin heater is running, and never overnight.

Electric heaters remove the carbon monoxide risk but still need clearance and a properly rated power supply. Keep at least a metre between any heater and stored materials, tools, chemicals or fabric, plug portable heaters directly into a switchboard with RCD safety switch protection rather than daisy-chaining extension leads, and never leave a heater running unattended.

Get gas and diesel heaters serviced before winter each year rather than after a fault shows up. A yearly check confirms the burner, seals and flue (if fitted) are still working as intended, which is a small cost against the risk of a slow gas leak going unnoticed in a shed you’re not in every day.

Which Shed Heater Is Best for Your Shed

Every heater type suits a different setup. Use this comparison to match a heater to how you actually use your shed, then check the sizing guide below before you buy.

How to Size a Heater for Your Shed

As a rule of thumb, plan for roughly 40 to 60 watts per square metre in a properly insulated shed, and closer to 100 watts per square metre if the shed is uninsulated. A 20m² insulated workshop, for example, needs somewhere between 800W and 1,200W of heating capacity to hold a comfortable temperature.

Ceiling height changes this figure. A shed with a high-pitched roof or a mezzanine has more air volume to heat, so multiply your estimate by 1.2 to 1.5 if the ceiling sits well above the standard 2.4m.

When in doubt, size up slightly rather than running an undersized heater flat out for hours, which wastes power without properly warming the space.

Multiple smaller heaters positioned around a large shed often heat more evenly than one large unit in a corner, particularly in a workshop where you move between different work zones through the day.

Worked example: a 40m² insulated workshop with a 2.4m ceiling sits at the lower end of the 40 to 60 watts per square metre range, so plan for roughly 1,600W to 2,400W of total heating capacity. That could be a single 2,000W oil column heater run centrally, or two 1,000W ceramic panel heaters mounted at either end of the shed for more even coverage across the space.

What Does It Cost to Run a Shed Heater

Running costs vary more by heater type than most people expect, and insulation affects the total more than the heater choice does. Independent Australian heater running-cost data gives a useful benchmark, summarised below at typical unit sizes.

These figures assume standard electricity and gas tariffs, and yours will vary depending on your plan and location. A thermostat and timer make a bigger difference to your actual bill than the sticker price of the heater, since most of the running cost comes from hours left on rather than the wattage itself.

The bigger lever is almost always insulation. A well-sealed shed needs less heater output to hold the same temperature, which is where the real savings come from rather than switching between heater brands or types.

How often you actually use the shed matters as much as the hourly rate. A heater running two hours on a Saturday morning costs very little regardless of type, so the cost differences above only really bite once you’re heating a shed daily through winter, such as a home workshop or a farm office used most days of the week. If that’s your situation, it’s worth running the numbers on your own usage pattern before choosing a heater type.

Why a Well-Built Insulated Shed Needs Less Heating

The most effective way to cut a shed’s heating bill is to need less heating in the first place. A shed built with proper wall and roof insulation from the outset holds warmth far better than one retrofitted after the fact, which is where the build itself starts to matter as much as the heater you choose.

Action Sheds Australia is a family-run business that has supplied and erected thousands of steel sheds across Australia, from residential sheds and rural sheds on working farms through to mining sheds built for remote-site conditions. Every Action Sheds build is ShedSafe certified and meets the Building Code of Australia, with climate, terrain and wind exposure factored in at the design stage rather than applied as an afterthought.

That matters for heating specifically because insulation and vapour barriers are far simpler to specify correctly when the shed is being designed than to add in later around existing framing and cladding. If comfort through winter is a priority for how you’ll use the shed, raise it during the design conversation rather than treating it as a follow-up job once the shed is up.

For anyone using their shed as a genuine workshop through winter, we’ve also covered why sheds make great winter workshops, including how layout and insulation choices affect year-round usability well beyond just heating.

Frequently Asked Questions

What Is the Safest Heater for a Shed?

Electric heaters are the safest choice for an enclosed shed because they don’t produce carbon monoxide. An oil-filled column heater or a ceramic panel heater with a tip-over safety switch and thermostat is the lowest-risk option if your shed has mains power.

If you need a fuel-burning heater because there’s no power connection, choose a model rated specifically for indoor or enclosed-space use, never an outdoor patio heater, and pair it with a carbon monoxide detector. Look for a model with a tested oxygen depletion sensor as an extra safeguard.

Can I Heat My Shed With Solar Power?

Yes, with the right setup. A small solar panel charging a battery pack can run a low-wattage infrared or ceramic heater for a few hours a day, which suits sheds used occasionally rather than as an all-day workspace.

For longer or all-day heating, you’d need a larger solar array and battery bank to keep up, so weigh the upfront cost against how often you actually use the shed through winter. A battery-inverter combination also gives you backup power for lighting and small tools, not just heating.

How Can I Heat My Shed Without Electricity?

Without mains power, an LPG blue-flame heater, a paraffin heater, or a diesel heater running off a 12V battery are the main options. All three need active ventilation while running and a dedicated carbon monoxide detector, since none of them are safe in a fully sealed space.

A solar-charged electric heater is the safest off-grid option if your usage is occasional rather than continuous, since it removes the combustion risk entirely. Whichever fuel-burning option you choose, only run it in short blocks while you’re actively using the shed, not for background heat throughout the day.

How Can I Insulate My Shed for Free?

You can’t insulate a shed for nothing, but you can reduce the cost by focusing on draughts first. Weather-stripping around doors and windows is inexpensive and often makes a bigger difference than expected, and repurposed materials like old carpet or removalist blankets can cover a bare floor until you install proper insulation.

For a full breakdown of low-cost insulation options that still meet a reasonable standard, see practical shed insulation tips. Sealing gaps first also means whatever you do spend on insulation goes further, since draughts undo a lot of the benefit otherwise.

What Is the Cheapest Way to Heat My Shed?

Insulate first, then choose the heater with the lowest running cost for your situation. On the numbers, a reverse-cycle system or a flued gas wall furnace cost the least per hour to run, but only make sense if your shed already has power and ducting or a compliant gas connection.

For most shed owners without those, an oil column or ceramic panel heater paired with proper insulation delivers the same comfort for a fraction of the running time, which is usually more practical than installing a whole new heating system.

Get Your Shed Warm and Ready for Winter

Heating a shed in winter comes down to sequence: insulate and seal first, then choose a heater sized correctly for the space, and follow the safety rules that go with it. Skip the first step and even the best heater on this list will underperform.

If you’re planning a new shed or upgrading an existing one, insulation and heating are far easier to plan for at the design stage than to retrofit later.