Agile and Time-of-Use Smart Tariffs in the UK: Shifting Load to Cheap Windows

A smart tariff rewards you for using electricity when it's cheap and penalising you — sometimes heavily — when it's dear. For some households it quietly knocks hundreds of pounds off the annual bill. For others it makes things worse, or simply isn't worth the faff. This guide explains how time-of-use pricing works in Great Britain, which loads actually move the needle, and the catch nobody mentions in the adverts.

What a time-of-use tariff actually is

On a standard tariff you pay one unit rate all day. As at 2026, the Ofgem price cap puts a typical electricity unit rate around 24.67p/kWh, with a standing charge on top — but your own bill is the only number that matters, because many people are on fixed or smart tariffs that differ from the cap. The cap resets every quarter, so treat that figure as a snapshot, not a constant.

A time-of-use (TOU) tariff charges different rates at different times. The common UK flavours:

• Economy 7 — the legacy version: roughly seven cheap overnight hours, dearer the rest of the day. Still widely available and good for storage heaters, a battery or heating your hot water cylinder overnight.
• Intelligent Octopus Go — a cheap overnight window (around 7p/kWh, but verify the current rate) aimed at EV and battery charging.
• Cosy Octopus — cheap windows tuned to how a heat pump runs through the day.
• Agile Octopus — the fully variable one: a different price every half-hour, linked to the wholesale market, published a day ahead. On windy or sunny days it can even go negative — they pay you to use power. On cold, still evenings it can spike well above the standard rate.

Every one of these requires a working smart meter (SMETS2). Northern Ireland runs a separate energy market, so these GB tariffs generally don't apply there — check locally if that's you.

Which loads are worth shifting

The whole game is moving flexible, chunky loads into the cheap window and keeping them out of the expensive one. The loads that genuinely pay:

• EV charging — the single biggest win. A car battery is huge; charging it overnight at ~7p instead of a daytime ~25p+ rate is where most people recover the cost of switching.
• Home battery — charge cheap overnight, discharge through the pricey evening peak. A battery also unlocks premium export tariffs such as Intelligent Octopus Flux, which requires one.
• Hot water — run the immersion or heat the cylinder in the cheap window rather than on demand.
• Washing machine, dishwasher, tumble dryer — delay-start timers cost nothing and move an easy chunk of use overnight.

What doesn't shift well: your fridge, lighting, router, and anything you need at 6pm — which is precisely when prices tend to be highest.

The catch with variable pricing

This is the part the comparison sites gloss over.

Agile-style tariffs are genuinely variable — there is no fixed unit rate to plan around. The negative-price headlines are real but occasional; the flip side is that on cold, still winter evenings the peak price can climb far above a standard tariff. If your life doesn't bend around the price signal — if you can't defer the oven, the kettle and the heating during a spike — a wholesale-linked tariff can bite.

Even the structured tariffs (Go, Cosy) have a trade-off baked in: the cheap window is subsidised by a higher rate outside it. The maths only works if you shift enough load into the cheap hours to earn back the daytime premium. There's also an effort cost — timers to set, an app to watch, charging to schedule. Some households love it; some quietly drift back to a dull fixed tariff and are happier for it.

And one practical warning: smart tariff rates change with 30 days' notice. The ~7p overnight figure that made the sums work today can move. Never commit to a long-term kit decision — a battery, say — on the strength of a rate that a supplier can revise. Verify the current rate before you count on it.

Does a battery change the picture?

A home battery is the classic companion to a smart tariff: charge it cheap, run the house off it at peak, and with the right export tariff sell surplus back. The catch is that there's no subsidy for a general household — the entire case rests on the tariff, and tariffs move. Indicative battery paybacks run around 7 to 12 years, and that range swings hugely with your unit rates, how much you can self-consume and which export deal you're on. 0% VAT applies on home batteries (including standalone retrofit) until 31 March 2027, which helps the upfront cost — but it doesn't rescue a weak usage case.

How to work out if it's for you

• Read your actual bill: unit rate, standing charge, and whether you're already on Economy 7 or a smart tariff.
• Estimate the share of your usage you can genuinely move overnight or into cheap windows.
• Check you have (or can get) a working SMETS2 smart meter.
• For an EV, model charging at the overnight rate versus your flat rate — that's usually the decisive number.
• Confirm the current rates before deciding; they change with 30 days' notice.

We don't sell tariffs, batteries, EV chargers or referrals, and no supplier pays us a penny — not even the "free" comparison sites can say that, because they're paid by whoever they sign you up with. Our only job is to tell you, from your own numbers, whether shifting your load to a smart tariff genuinely pays — or whether a plain fixed rate quietly suits you better.

Figures in this guide are current at the date of publication and indicative only — SEG/export rates change with 30 days' notice, the Ofgem price cap resets quarterly, and grant terms change. Confirm the current numbers for your situation before you commit. This is general information, not personal financial advice.