The first proper cold snap in May does the same thing every year: everyone drifts inside by 7pm and the alfresco sits empty until October. A heater fixes that. What stops most people is not choosing a unit, though — it is wondering what the thing will do to the next power bill. Almost every answer online quotes a cents-per-hour figure pulled from a tariff that was never yours. Outdoor heater running costs are simple arithmetic, and the only rate that matters is the one printed on your own bill.
So this guide hands you the method instead of a made-up number: the calculation for electric radiant heat, the megajoule-to-dollars conversion for LPG gas, and an honest way to think about firewood. Everything is worked from what the product pages state. Browse the full outdoor heating range as you read.
How to work out outdoor heater running costs
Every heater burns one of three fuels: electricity, LPG or wood. Each has its own unit — kilowatt-hours, megajoules, bags of firewood — and the job is converting that unit into dollars per hour.
We are not handing you a cents-per-hour figure because energy prices vary by state, retailer, plan and time of day. A rate that is right in regional Victoria is wrong on a time-of-use plan in Sydney. On your bill it is the usage charge, in cents per kilowatt-hour (c/kWh). For LPG, it is whatever you paid at your last 9 kg bottle swap.
Electric radiant heat: multiply two numbers and you are done
Electric is the easiest fuel to cost, because a radiant heater turns essentially all the electricity it draws into heat. The formula is:
Running cost per hour = heater rating in kilowatts × your electricity rate in dollars per kWh
Take the Heatstrip Max Infra-Red Heater 2400W ($799). Its product page states 2400W, which is 2.4 kW. Assume a rate of 35c/kWh — a round figure chosen purely for illustration, not a quoted tariff — and the sum is 2.4 × $0.35 = 84 cents an hour at full output.
Substitute the c/kWh figure off your own bill and the answer changes immediately. On a time-of-use plan, use the peak rate — outdoor heating happens in the evening. Radiant heat warms people rather than air, so aim the unit at the seats.
LPG gas: turning megajoules into dollars
Gas heaters are rated in megajoules per hour (MJ/h) rather than watts, so there is one extra step. The conversion is fixed: 3.6 MJ equals 1 kWh of energy.
The Heatstrip Portable Gas Heater ($1,124) states a 34 MJ four-tile ceramic burner running off a 9 kg LPG bottle. Work it in two steps.
Step one, hours per bottle. A 9 kg LPG cylinder holds roughly 430 MJ. Divide by the burner rating: 430 ÷ 34 is about 12.5 hours at full output.
Step two, cost per hour. Divide what the swap cost you by those hours. If a bottle swap cost $30 — again, an assumed figure, use your own receipt — that is roughly $2.40 an hour.
That looks dear next to 84 cents until you notice how much more heat you are buying. Divide 34 MJ/h by 3.6 and the gas unit puts out about 9.4 kW, near four times the 2.4 kW electric strip. Per kilowatt-hour of delivered heat it lands around 25 cents against the electric heater's 35 cents, because electric costs you exactly your tariff.
The real trade-off is fuss, not price. Gas means bottles to swap; electric means a power point or an electrician. The 34 MJ unit also needs 500mm of overhead clearance.
Fire pits and wood heaters: cost per evening, not cents per hour
Firewood is not sold in kilowatt-hours. It comes by the bag, the barrow or the cubic metre, so the only honest unit for a wood fire is cost per evening. Note what a bag costs locally, then count how many fires you get from it.
A Firepit 72cm ($299) is the cheapest way into outdoor heat by a wide margin, and its running cost is whatever firewood costs where you live. The 72cm cast iron bowl is 25cm deep, so it takes a solid load. That is also why it gets through wood quickly: an open fire sends most of its warmth straight up.
Worth clearing up, because the outdoor heating collection can confuse at a glance: the Blaze range is wood-burning, not electric. The Blaze B600 ($2,699) is a flued freestanding wood heater rated at 87% efficiency, with 170 square metres of coverage. That is a different class of appliance to a patio heater, suited to an enclosed indoor-outdoor room. That rating is why a closed firebox and an open fire pit burning identical wood deliver such different usable warmth. The electric Heatstrip units are a separate range.
Which heater costs least for your area
| Heat source | What you pay for | The number to find | Best suited to |
|---|---|---|---|
| Electric radiant | Your usage tariff | c/kWh, peak rate at night | Covered alfresco, balconies, dining zones |
| LPG gas | Bottle swaps | Swap price ÷ hours per bottle | Large open areas, no power point nearby |
| Open fire pit | Firewood by the bag | Bag price ÷ evenings per bag | Open paved areas, atmosphere first |
| Flued wood heater | Firewood, burned efficiently | Bag price ÷ evenings | Indoor-outdoor rooms with a flue |
The pattern repeats whichever brands you compare. Electric wins on convenience and small sheltered areas. Gas wins where there is no power nearby, or the space is large and open. Fire pits win on atmosphere and upfront price.
The Australian factors that change the maths
Rooftop solar. With panels, an electric heater running at 4pm in May costs you your feed-in tariff rather than your usage rate, often a fraction of it. Run it at 8pm and you are paying peak.
Total fire ban days. A fire pit has a running cost of zero on days you cannot light it. Solid-fuel fires are restricted during declared fire danger periods and total fire bans, and rules differ between states and councils. Check with your local council and your state fire service — the NSW Rural Fire Service and Victoria's CFA both publish daily district ratings.
Strata and balconies. Plenty of bodies corporate ban LPG bottles and open flame on balconies while permitting a fixed electric heater. In an apartment, read the by-laws before comparing running costs at all. Our guide on choosing between a firepit or a patio heater covers placement and clearances.
Outdoor heater running costs — frequently asked questions
Is an outdoor heater expensive to run?
That depends on your tariff and how long you run it, which is why a single figure misleads. A 2.4 kW electric radiant heater at an assumed 35c/kWh works out to 84 cents an hour at full output. Apply your own rate, and remember most households heat for two or three hours an evening, not all night.
Is gas or electric cheaper for outdoor heating?
Per unit of heat delivered, LPG usually works out cheaper than electricity in Australia, but per hour a large gas heater costs more because it produces far more heat. Compare them by dividing each one's cost per hour by its output in kilowatts. Electric gets cheaper when rooftop solar covers the load.
How many hours does a 9 kg LPG bottle last in a patio heater?
Divide roughly 430 MJ by the heater's MJ/h rating. A 34 MJ burner gives about 12.5 hours at full output, and considerably longer turned down. The sum is the same regardless of brand, and the burner rating is on the product page.
Do outdoor heaters still work in the wind?
Radiant heaters keep working in a breeze because they warm people and surfaces directly rather than heating the air. Convected warmth, including most of what an open fire pit throws off, gets carried away. Blocking the wind is the cheapest heating upgrade there is.
Shop the range
Whichever fuel suits your area, do the sum before you buy. For the cheapest way to test the idea, the Heatstrip Nano Infra-Red Wall Mount Heater ($269) is the entry point to the electric line-up. The full heating and fire range ships Australia-wide with free delivery over $100, and most orders are dispatched in 3-10 business days.
