What two energy retailers actually publish
AGL's winter tips page states plainly that "a hot water bottle or warm wheat bag can warm your body and uses less energy than an electric blanket." It doesn't put a number on the gap. EnergyAustralia's own published calculations do, for the kettle side of the comparison: boiling 1.5 litres of water from 20°C to 100°C in a 2.2 kW electric kettle takes 0.14 kWh, a typical hot water bottle's fill. EnergyAustralia separately recommends running an electric blanket for "10 to 30 minutes on an average setting before switching it off" rather than all night, matching the 20-30 minute pre-warm window our own calculator's FAQ already recommends. Put those two real, sourced numbers against each other and the answer changes depending on which way the blanket's actually being used.
What this costs, state by state
A queen electric blanket's pre-warm session (50 W average draw, the same figure our calculator above uses, run for 25 minutes) against one kettle boil for a hot water bottle (EnergyAustralia's own published 1.5 L, 20–100°C figure).
| State | Rate | Electric blanket, 25-minute pre-warm | Hot water bottle, one kettle boil (1.5 L) |
|---|---|---|---|
| New South Wales | 32.4¢ | 1¢ | 5¢ |
| Victoria | 29.8¢ | 1¢ | 4¢ |
| Queensland | 31.2¢ | 1¢ | 4¢ |
| South Australia | 38.1¢ | 1¢ | 5¢ |
| Western Australia | 33.6¢ | 1¢ | 5¢ |
| Tasmania | 28.9¢ | 1¢ | 4¢ |
| Australian Capital Territory | 27.4¢ | 1¢ | 4¢ |
| Northern Territory | 31.7¢ | 1¢ | 4¢ |
Reference rates for 2026–27. Your row is highlighted once you set your location.
Why AGL's advice is only half the picture
AGL is right if the comparison is a hot water bottle against a blanket left on all night: our own calculator's table above already shows a queen blanket running the full 8 hours costs 11 to 15 cents a night depending on state, against 4 to 5 cents for one kettle boil, a genuine win for the hot water bottle. But nobody serious about the electricity bill runs a blanket that way. Used the way EnergyAustralia itself recommends, pre-warmed for 20 to 30 minutes and switched off before the doona traps the heat, a queen blanket costs about a cent a night in every state (the table above rounds to the nearest cent; the real figure is under one), cheaper than the kettle it takes to fill a hot water bottle.
The two aren't really interchangeable either. A hot water bottle holds its heat for hours without drawing any more power once it's filled, useful if it's moving around the bed or warming your feet directly. A pre-warmed blanket needs the bed already occupied to trap what it's put in, and does nothing for a second warm-up later in the night without switching back on. Cost isn't the only difference, but on cost alone, the honest answer is "it depends how you use the blanket," not a flat yes or no.
Common questions
Is a hot water bottle cheaper to run than an electric blanket?
It depends on how the blanket is used. Against a blanket left on all night, a hot water bottle wins clearly, about a third of the cost. Against a blanket pre-warmed for 20 to 30 minutes and switched off, the recommended way to use one, the blanket costs less than a single kettle boil.
How much energy does it take to fill a hot water bottle?
About 0.14 kWh, EnergyAustralia's own published figure for boiling 1.5 litres of water from 20°C to 100°C in a 2.2 kW kettle. That works out to roughly 4 to 5 cents on current state electricity rates.
Is it cheaper to leave an electric blanket on all night instead of using a hot water bottle?
No. A queen electric blanket left on for a full 8 hours costs 11 to 15 cents a night depending on state, against 4 to 5 cents for the kettle boil that fills a hot water bottle. Pre-warming the blanket and switching it off, rather than leaving it on all night, closes that gap and then some.
Is there a cheaper way to heat the room itself, not just the bed?
Worth checking alongside this page. Our cheapest way to heat a room guide finds reverse cycle air conditioning heats a room for about a third of any plug-in heater's cost, useful context if the real goal is a warm room rather than just a warm bed.
Sources
Hot water bottle energy claim: AGL, How to stay warm and save energy this winter. Kettle energy use (1.5 L, 20–100°C, 2.2 kW kettle, 0.14 kWh per boil): EnergyAustralia, How much electricity use can you get for $1?. Electric blanket running cost and 10-30 minute pre-warm recommendation: EnergyAustralia, Why you should use an electric blanket this winter. Blanket average draw (queen, 100 W rated, 50 W average): the same figure our electric blanket running cost calculator uses. Electricity rates: AER Default Market Offer and each state's regulated reference tariff, current for 2026–27. All fetched July 2026.