Understand it · practical guide
Off-peak electricity: how time-of-use tariffs save money
In one line: Economy 7, EV plans and smart time-of-use deals pay you for moving the same laundry to the night. Who benefits, who does not, and the household shifts that make the tariff work.
Most homes pay one flat rate for every kWh, but generating electricity is not flat-cost: power at 3 am is far cheaper than power at 6 pm. Time-of-use tariffs pass some of that difference to you - a cheap overnight window (Economy 7's seven night hours in the UK, overnight EV and off-peak plans in the US and Australia, smart-tariff half-hour pricing where smart meters allow) and a pricier daytime rate to balance it. Whether that trade suits the house depends entirely on when the house can use its power.
Who wins immediately
Homes with a big shiftable load: an EV charging overnight is the textbook case - the same miles cost a fraction at night rates. Close behind: households with a night storage heater, a timer-capable washer, dryer or dishwasher, or anyone whose water heater can heat its tank in the cheap window for the next day. A smart plug or the machine's own delay button is the whole technology required for the laundry-class wins.
Who should stay flat-rate
The all-evening household: dinner cooked at 7, laundry dried at 8, heating and lights through the peak - on a time-of-use tariff those exact hours are the expensive ones, and a rate plan cannot rescue a usage pattern that lives on the peak. If nothing in the house can run unattended at night, the cheap window earns nothing while the expensive hours carry the whole bill. The honest test is a week of noting when the house actually draws power (the meter test in the bill diagnosis doubles as the survey) and checking what share could move.
The shifts that make it work
Run the washer, dryer and dishwasher on delay timers overnight; heat the water tank in the cheap window; charge everything with a battery - phones, laptops, the EV - while you sleep; and where the plan prices it sensibly, pre-heat or pre-cool the house slightly before the peak and let the insulation hold it through the expensive hours. Pair the tariff with the habits that work at any rate - the standby cleanup and the thermostat discipline from the smart-thermostat payback maths (many smart models automate the peak-shifting for you). Read any tariff's small print for its peak-window definition and its standing charge - the cheap night rate means little if the day rate or fixed fees swallow the savings.
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General information, not professional advice. Homes differ — if a job is beyond your confidence or the guide’s boundary, that is what tradespeople are for.