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Reverse cycle heating cost per hour and year

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A typical 7.1 kW split in the Average climate zone uses about 1,003 kWh of heating energy a year on its label, about $321 at 32c/kWh. Flat out it costs about $0.65 an hour to heat, and a typical hour is nearer $0.18.

Your air conditioner

Median of the models on the Energy Rating registry.

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Between 0 and 20,000

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Type the figures for your zone from the Zoned Energy Rating Label.

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Yearly cost from the label

$321a year

1,003 kWh × 32c/kWh
7.1 kW split, Average zone (suggested default)

Heating a year
$321
Per hour, flat out
$0.65
Per typical hour
$0.18

Two methods, side by side. The yearly cost uses the label. The per-hour figures use rated input. A typical hour is our estimate.

Tip. Each degree cooler in summer or warmer in winter adds about 5–10% to energy use. Try 25–27 °C in summer and 18–20 °C in winter.

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How we calculated this

  • The yearly cost is the kWh on the Zoned Energy Rating Label for the climate zone, times the electricity rate.
  • The cost per hour flat out is the rated input in kW times the rate.
  • A typical hour costs less, because an inverter slows down once the room is at temperature. That part is an estimate.

Full method, tables and sources: Air conditioner running cost calculator

  1. Read the label kWh for your zone

    Heating 1,003 kWh · Total 1,003 kWh (Average zone, registry median)

  2. Multiply by your rate

    1,003 kWh × 32c/kWh = $321 a year

  3. Cost per hour, flat out

    Heating: 2.04 kW × 32c/kWh = $0.65.

  4. Cost per typical hour (Estimate)

    Heating: $0.65 × 27% = $0.18.

Every size at your zone, use and rate
SizeLabel kWh a yearCost a year
2.5 kW split368$118
3.5 kW split460$147
5 kW split700$224
7.1 kW split1,003$321
8 kW split1,159$371
10 kW split1,468$470
10 kW ducted1,545$494
12.5 kW ducted1,918$614
14 kW ducted2,210$707
16 kW ducted2,573$823
18 kW ducted3,017$965
20 kW ducted3,294$1,054

This version counts heating only. It uses the red heating figure on the label for your climate zone. In the Cold zone, heating uses about 7 to 9 times the kWh of cooling.

Heating with a reverse cycle air conditioner

Not yet checked

  • Reverse cycle air conditioners are 300% to 600% efficient. A plug-in resistance heater is 100% efficient: 1 unit of electricity gives 1 unit of heat. (energy.gov.au, heating and cooling)
  • Heating output and efficiency drop when the outdoor coil frosts, below about 5.5 °C outside. In frosty areas, check that the label’s 2 °C heating capacity is not much lower than the 7 °C figure. (GEMS Regulator, zoned label Q&A Q12 and installer guide p11)

Official source

  • Set 18–20 °C in winter. Each degree warmer adds about 5% to 10% to your heating energy. (YourHome and energy.gov.au, heating and cooling)
Reverse cycle heating: what every split size costs a year to heat in each climate zone, and an hour flat out, at 32c/kWh
SizeHot zoneAverage zoneCold zoneAn hour of heating
2.5 kW split$18$118$305$0.22
3.5 kW split$22$147$395$0.29
5 kW split$33$224$615$0.44
7.1 kW split$45$321$895$0.65
8 kW split$52$371$1,030$0.77
10 kW split$67$470$1,277$0.92
  • The same 7.1 kW split costs $45 a year to heat in the Hot zone, $321 in the Average zone and $895 in the Cold zone: about 20 times as much in the Cold zone as in the Hot zone.
  • Heating is the bigger part of the 7.1 kW split's label in 2 of the 3 zones: 1,003 kWh a year against 594 for cooling in the Average zone and 2,796 kWh a year against 377 for cooling in the Cold zone. In the Hot zone cooling is the bigger part: 140 kWh of heating against 1,733.
  • At its rated point the 7.1 kW split turns 2.04 kW of power into 8 kW of heat: 3.92 kW of heat for each kW it draws. At 32c/kWh that is about 8.2c for a kWh of heat, against 32c from a plug-in heater that gives 1 kWh of heat for each kWh.
  • Each degree warmer adds about 5% to 10% to heating energy. On the $895 a year of the 7.1 kW split in the Cold zone that is about $45 to $90 a year for each degree.

Each row is the median of the split models of that size on the Energy Rating registry (Official source), run through the calculator on this page with cooling switched off. The rate is 32c/kWh, our plain average of the state default rates: Dated third-party source, except Western Australia (Official source). The zones are the three on the energy label (Official source). Hot: Brisbane and Darwin. Average: Adelaide, Perth and Sydney. Cold: Canberra, Hobart and Melbourne. An hour flat out is an hour at the rated heating input, times the rate. It is not a typical hour, and our data holds no figure for the most a unit can draw. The 5% to 10% for each degree is a rule of thumb (Official source). Source: energy.gov.au Heating and cooling (Wayback copy, 18 Sep 2026); YourHome Heating and cooling (Wayback copy, 29 Sep 2026).

Heating against a plug-in heater, and a typical hour

An hour of a plug-in heater against an hour of a split

Rated power of plug-in heaters: 2,400 W for an oil column heater, 2,200 W for a panel heater and 2,000 W for a fan heater.

Source: CHOICE electric heater lab tests, updated 27 May 2026 (Dated third-party source). Checked 23 September 2026.

Flat out at 32c/kWh, the 2,400 W heater costs $0.77 an hour and gives 2.4 kW of heat. The 2.5 kW split, the smallest in the table above, costs $0.22 an hour flat out and gives 3.2 kW of heat at its rated point. For your own room size and hours, use the heater running cost comparison.

A typical hour of heating, by zone

Our estimate of the average draw when heating, as a share of the rated input: 25% in the Hot zone, 27% in the Average zone and 50% in the Cold zone.

Source: WattMaths engineering estimate from registry label kWh and reported (unconfirmed) zone hours (Estimate). Checked 1 October 2026.

For the 7.1 kW split that makes a typical hour of heating about $0.16 in the Hot zone, $0.18 in the Average zone and $0.33 in the Cold zone, against $0.65 flat out. The table above shows the flat out figure: an hour at the rated input.

Compare with a plug-in heater

New to the label method? Read the full guide on the main air conditioner running cost calculator.