How appliance running costs are worked out
Watts are the power an appliance draws. Divide by 1,000 for kilowatts and multiply by the hours it runs to get kilowatt-hours (kWh), the units on your bill. Multiply the kWh by your rate for the cost.
Say you run a split system rated 1,500 W input for 6 hours a day, 5 days a week, a TV at 100 W for 4 hours a day and a pool pump at 750 W for 6 hours a day, every day:
- Split system: 1,500 ÷ 1,000 × 6 h × 5 days = 45 kWh a week
- TV: 100 ÷ 1,000 × 4 h × 7 days = 2.8 kWh a week
- Pool pump: 750 ÷ 1,000 × 6 h × 7 days = 31.5 kWh a week
- Together: 79.3 kWh a week × 365 ÷ 7 = 4,134.929 kWh a year
- At 33.2621c a kWh: $1,375.36 a year, or $114.61 a month (a twelfth of the year)
Rates and figures the calculator uses
Synergy rates and figures in the appliance running cost calculator
| Figure | Value | Used for |
|---|---|---|
| Synergy Home Plan (A1) | 33.2621c per kWh, any time | The starting rate |
| Midday Saver, 9am–3pm | 8.8520c per kWh | Rate choice |
| Midday Saver, 9pm–9am | 24.3431c per kWh | Rate choice |
| Midday Saver, 3pm–9pm | 55.3253c per kWh | Rate choice |
| Home Plan (A1) supply charge | 119.2419c a day | Information line only, not in the totals |
| Midday Saver supply charge | 132.7806c a day | Information line only, not in the totals |
| Weeks in a year | 365 ÷ 7 | Yearly kWh and cost (arithmetic) |
| Months in a year | 12 | Monthly cost (arithmetic) |
Synergy's published prices from 1 July 2026, including GST. Midday Saver needs an advanced (AMI) meter and is only offered in suburbs where AMI is available. Checked 22 October 2026.
Also available as a free WordPress plugin: WattPencil Appliance Running Cost.
Finding an appliance's input watts
Check the rating label on the appliance, or its manual or specifications. If the figure is in kilowatts, multiply by 1,000 for watts.
In stores, fridges and freezers, washing machines, dryers, dishwashers, TVs, computer monitors, pool pumps and many air conditioners carry the Energy Rating Label. Its energy consumption figure is the kWh a year from standardised testing, based on how most people use that kind of appliance, so your own use may be higher or lower. Multiply it by your rate for a yearly cost. To enter it here, divide the yearly kWh by 8.76 and enter that as the watts, at 24 h a day and 7 days a week: a year has 8,760 hours, so the calculator gives back the label's yearly kWh.
Air-con, pool pumps, hot water and dryers
Enter your own appliances' figures. For the ones that tend to run longest or draw the most:
- Air-conditioning: use the input power from the label, not the cooling or heating capacity, and the hours the unit actually runs at that power. Weighing up ceiling fans instead? Enter the fan's watts from its box or manual, and see AC vs DC ceiling fans and ceiling fan installation.
- Pool pump: the watts from its label, and the hours set on its timer.
- Electric hot water: a storage heater's element only runs while it's heating, so enter the hours it heats rather than the whole day.
- Clothes dryer: the watts, the hours a load takes as the hours a day, and loads a week as the days.
Cutting appliance running costs on Synergy plans
On Midday Saver, 9am to 3pm costs 8.8520c a unit, against 55.3253c from 3pm to 9pm and 24.3431c overnight. Moving a pool pump's timer, the dishwasher or the dryer into the middle of the day lowers their cost at those rates: choose each rate above to compare. The plan's supply charge is higher,132.7806c a day against 119.2419c on the Home Plan (A1).
With your own solar, power you'd otherwise export earns Synergy's DEBS buy-back: 10c a unit from 3pm to 9pm and 2c at other times (effective as at 1 July 2025). For an appliance that runs on your own solar before 3pm, the cost is the 2c export credit you give up, so enter 2 as your own rate; from 3pm it's the 10c. To store solar for the evening, try the battery rebate calculator and the solar battery cost guide; for a car, the EV charging calculator.
