← All guides

Is a time-of-use tariff worth it for you?

A time-of-use tariff — like Octopus Agile or an EV/“go” tariff — charges different prices at different times of day: cheap when demand is low, dearer at peak. Whether that’s a brilliant deal or an expensive one comes down entirely to when you use your energy.

• How it works. Instead of one flat unit rate, you pay less in off-peak windows (often overnight, and with Agile the price varies every half-hour) and more at peak, typically the early evening. Shift use into the cheap windows and you win; use most of your power at peak and you can pay more than a flat tariff. Economy 7 is the classic version →
• When it pays off. If you’ve got a big, shiftable load you can move into the cheap window — an EV charging overnight, a heat pump, a home battery, or even just running the dishwasher and washing machine at off-peak times — the savings can be real and meaningful.
• When a flat tariff wins. If your life happens in the evening peak and you can’t easily move it — cooking, heating, telly all between five and eight — the dearer peak rate can outweigh the cheap window, and a steady flat tariff is the safer bet. How to find the cheapest for your usage →
• The real test. It’s not about how much energy you use — it’s about how much of it you can move. A home that can shift half its usage into the cheap window is a different case from one that can’t shift any, even if their total bills are identical.

You don’t have to switch to feel how a time-of-use tariff behaves. Joulely’s live “is now a good time?” feature shows the cheapest upcoming Agile half-hour and the greenest window right now — so you can see, today, whether shifting a load would actually pay off before committing to anything.

And because the real answer depends on your own half-hourly pattern, we model time-of-use tariffs against your usage — not a typical home — and tell you straight whether one wins, free and impartial.