Off-peak windows, time-of-use tariffs and solar-sponge rates mean when you use power can matter as much as how much. Here is how to shift load and pay less.
On a single-rate (flat) plan the answer is simple: electricity costs the same at 2am as it does at 6pm, so timing does not change your bill. But a large and growing share of Australian homes are now on a time-of-use tariff, where the price per kWh changes through the day. On those plans, when you use power can matter almost as much as how much you use.
A time-of-use tariff splits the day into peak (the expensive window, typically weekday late afternoon and evening when the grid is busiest), off-peak (the cheapest, usually overnight and often weekends), and shoulder (the times in between). The exact hours are set by your local network, not just your retailer, so they differ by state and area. Always check your own bill for the precise windows.
Off-peak, and the new "solar sponge" middle of the day
Traditional off-peak is overnight, commonly from late evening until early morning. That is when running the dishwasher, washing machine, dryer, pool pump or an EV charger costs least on a time-of-use plan. Controlled-load tariffs for hot water and pool pumps push those loads into the small hours automatically at a very low rate.
A newer wrinkle is the daytime "solar sponge" or "solar soak" period. Because rooftop solar now floods the grid in the middle of the day, several networks have introduced very cheap daytime rates (sometimes cheaper than overnight) to encourage households to use power when it is abundant. If your plan has one, the middle of the day can be the cheapest time of all to run big appliances, even without your own panels.
How to shift load without changing your life
Find your windows: check your bill or your retailer app for your exact peak, shoulder, off-peak and any solar-sponge hours. They vary by network.
Use timers and delay-start: set the dishwasher, washing machine and dryer to start in the off-peak or solar-sponge window rather than during the evening peak.
Automate the big loads: put hot water and pool pumps on controlled load or a timer so they run at the cheapest time without you thinking about it.
Charge overnight: schedule an EV or battery charge for the off-peak window. It is often the single biggest load you can move.
Avoid stacking the peak: try not to run the oven, air conditioner, dryer and pool pump all at once in the late-afternoon peak.
Is a time-of-use plan even right for you?
Time-of-use only saves money if you can genuinely move load into the cheap windows. A household that is out all day and uses most of its power in the evening peak may actually pay more on time-of-use than on a flat rate. There is no universal winner. It depends entirely on your pattern.
EnergySorted settles the question by costing both structures against your real usage. It applies your actual peak and off-peak split across every plan, takes no retailer commission, and shows whether a flat rate, a time-of-use plan or a solar-sponge tariff genuinely costs you least. Its off-peak and time-of-use optimisation view highlights how much you could save by shifting specific loads.
Frequently asked questions
What is the cheapest time to use electricity?
On a time-of-use plan it is off-peak, usually overnight, and increasingly the middle of the day where a "solar sponge" rate exists. On a single-rate plan the price is the same all day, so timing makes no difference. Check your bill for your exact windows because they are set by your local network.
What are typical off-peak hours in Australia?
Off-peak is commonly overnight, often from late evening to early morning, and frequently includes weekends. The precise hours vary by network and state, so the only reliable source is your own bill or retailer app rather than a general rule.
What is a solar sponge or solar soak tariff?
It is a very cheap daytime rate offered by some networks to encourage households to use power when abundant rooftop solar is flooding the grid. Where available it can make the middle of the day the cheapest time to run big appliances, even if you do not have your own panels.
Should I switch to a time-of-use plan?
Only if you can shift real load into the cheap windows. If you are home in the evenings and use most power during the peak, time-of-use can cost more than a flat rate. Comparing both structures on your actual usage (which EnergySorted does) tells you which genuinely wins for your household.
How much can shifting load actually save?
It depends on how much of your usage you can move and how big the gap is between your peak and off-peak rates. Moving an EV charge, hot water and laundry off the peak can be a meaningful saving, which EnergySorted quantifies through its time-of-use optimisation view.
How do I find my exact off-peak hours?
They are set by your local network, not just your retailer, so they vary by state and even by suburb. The reliable source is your own bill or retailer app, which lists the windows against each rate. Our guide to how to understand your electricity bill shows where the peak, shoulder and off-peak times appear.
When is the cheapest time to charge an EV at home?
Usually the overnight off-peak window, or the middle of the day if you have solar or a cheap daytime rate. Because an EV is often the single biggest load you can shift, getting the timing right matters. See what it costs to charge an EV at home and how the right window changes the figure.
Do demand charges change when I should use power?
Yes. On a demand tariff you also pay for your single highest half-hour of usage, so spreading big appliances out rather than running them all at once matters as much as the time of day. Our guide to demand charges explains how to keep that peak low.
Can I put my hot water and pool pump on a cheap off-peak rate?
Yes, that is exactly what a controlled load is for. Hot water and pool pumps can be wired to a separate register that only runs in the small hours at a very low rate, so two of your biggest loads shift to off-peak automatically without you lifting a finger.
Is a flat rate ever better than time-of-use for timing?
If you genuinely cannot move load out of the evening peak, a single flat rate can beat time-of-use because there is no expensive window to fall into. Timing only pays off when you can actually shift usage, so the honest test is to cost both structures on your real pattern.
Do weekends count as off-peak?
On many time-of-use plans, yes, weekends are charged at the off-peak or shoulder rate all day, which makes them a good time to run the dishwasher, laundry and other flexible loads. As always the exact treatment is on your bill, since networks differ.
General information only, current at the time of writing. Not financial advice. Rebate schemes and rules
change; always confirm details with your retailer or state government energy site.
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