The cheapest heater in Australia isn't the one in your spare room. It's the aircon on the wall.

Here is the bit the showroom never explains. A panel heater, a fan heater, an oil column and a bar heater are all the same machine underneath: a coil that turns a kilowatt of electricity into a kilowatt of heat. Pay for two thousand watts, get two thousand watts of warmth. That is the ceiling, and at the same wattage they all cost you exactly the same to run.

A reverse-cycle aircon cheats. It does not make heat, it pumps it in from the air outside, so a single kilowatt off your bill drags roughly three and a half kilowatts of warmth into the room. Same comfort, a quarter of the cost. The diagram below is to scale.

About 31% of Australian households rent (ABS Census 2021), and most cannot bolt a split system to the wall. That steers nearly a third of the country toward the priciest way to heat. Here is how to heat well without touching the building, in order of value.

1. 1

   Buy a portable reverse-cycle aircon

   A portable heat pump is the only plug-in unit that breaks the one-for-one rule, and good ones run from around $500. Check carefully that it is a true reverse-cycle heat pump, not a resistive heater dressed up in heating mode, or you lose the entire advantage.
2. 2

   Heat the person, not the room

   An electric blanket or heated throw draws only 60 to 150 watts, about 5c an hour, and costs under $48 across the whole winter on CHOICE testing. For sitting still or sleeping, nothing else comes close.

   5c

   Electric blanket

   22c

   Reverse-cycle

   43c

   Gas heater

   87c

   Panel heater

   Cost per hour at the NSW representative rate.

3. 3

   Heat one room and draught-proof it

   Pick the room you actually use, close the door, and seal the gaps. A door snake and some weather strip cost little and stop the warm air you are paying for from leaking straight out.
4. 4

   Match a resistive heater to the job, with a timer

   If a plug-in heater is all you have, size it to the space rather than buying the biggest one, and put it on a timer so it is not running in an empty or already-warm room.
5. 5

   Ask the landlord, and check your state rules

   A split system adds value for the owner too. Some states have minimum heating standards for rentals, so it is worth asking and worth knowing where you stand.

What is the cheapest heater to run in Australia?

A reverse-cycle air conditioner is the cheapest heater to run in every Australian state. Because a heat pump moves heat rather than making it, it delivers roughly 3 to 4 units of warmth for each unit of electricity, so it costs far less to run than any plug-in electric heater for the same warmth.

Are all plug-in electric heaters the same to run?

Yes, near enough. A panel heater, fan heater, oil column heater and bar heater are all resistive: every watt they draw becomes one watt of heat. Two heaters of the same wattage cost the same to run regardless of the marketing. The only electric heater that breaks this rule is a reverse-cycle unit, which is a heat pump.

Is gas cheaper than a reverse-cycle aircon?

In most states and most rooms, no longer. Electricity prices have steadied while gas prices have risen, so a reverse-cycle unit now beats gas on running cost across most of the country. Gas can still win for whole-home ducted heating, in alpine cold where heat pump efficiency drops, or where a household has a cheap legacy gas rate.

How much does a reverse-cycle aircon cost to run for winter?

It depends on your state, the room and the hours, which is why the calculator above lets you set all three. As a guide, heating a living room for a few hours a night across winter costs a fraction of what the same job costs on a plug-in heater.

I rent and cannot install a split system. What is cheapest for me?

Start with a portable reverse-cycle aircon, but check it is a true heat pump and not a resistive heater running in heating mode. Failing that, heat the person rather than the room with an electric blanket or heated throw, which costs only a few cents an hour. Then heat one room, draught-proof it, and match any plug-in heater to the size of the space with a timer.

Where do these running costs come from?

We model the heat each room needs, then cost it by heater type using current regulated and standing-offer electricity rates and representative gas rates. Every figure on this page comes from one shared engine, so the calculator, the state table and your own heater result always agree. See the methodology below for sources and assumptions.