How to compare the best Economy 7 tariffs
The best Economy 7 tariff is the one with the lowest suitable total cost for your day and night usage, not necessarily the lowest advertised night rate.
Prepared from existing project material on 24 October 2026. Editorial review: not yet recorded. Live figures use the current record; existing evidence dates are unchanged.
See also: Economy 7 explained · Economy 7 times · Is Economy 7 worth it? · Compare my Economy 7 costs · Octopus Go · Octopus Cosy · Octopus Agile
Compare your consumption before comparing suppliers
Start with annual consumption from both meter registers. Add day and night kWh to obtain total use, then divide night use by that total to find your night share. If the figures are estimated, submit readings or obtain an actual annual record before relying on a close comparison. Do not assume that owning storage heaters establishes a particular percentage of overnight consumption.
Keep the period consistent. Comparing winter night use with a full-year daytime estimate can exaggerate the benefit. If you are changing heating, your past split may no longer describe the future arrangement. Model that change separately and show the assumptions. The existing Economy 7 calculator accepts your own usage and rates rather than imposing a supposed universal break-even percentage.
Collect the same fields for every quote
For each offer, record the day rate, night rate, daily standing charge, tariff term, exit fees and the confirmed cheap hours. Check the meter requirements and whether the tariff is available for your address and payment method. Include VAT consistently. A supplier name alone does not identify a rate, because regional and product differences can change what is offered.
No current cheapest Economy 7 leaderboard is published here: the project does not hold a verified live set of comparable E7 offers. Rates from other Octopus products are not inserted as substitute Economy 7 prices. Obtain an actual quote and keep its date. A low night rate in an advertisement may not offset a higher day price for the way your household uses electricity.
Work out the annual cost
Multiply annual day kWh by the day rate and annual night kWh by the night rate. Add those costs and the standing charge for the whole year. When the rates are in pence, divide by one hundred to convert to pounds. Compare the same annual consumption against the alternative single-rate tariff and its standing charge.
The Economy 7 calculator represents any difference in standing charges as pounds per year. Enter the additional yearly charge for the E7 option, or a negative difference if it is lower. Exit fees are a separate switching consideration: do not hide them inside the unit rate. Review both the ongoing annual estimate and any cost of leaving your existing contract.
Understand the night-use break-even
The break-even point is the share of energy that must fall into the cheaper period for the two offers to cost the same. It depends on both day and night rates, the alternative standard rate, total annual kWh and the standing-charge difference. There is no single percentage that makes Economy 7 cheaper for every household.
In the usual case where the night rate is below the day rate, the fraction can be written as: day rate minus standard rate, plus the annual standing-charge difference converted to pence and divided by total kWh, all divided by day rate minus night rate. The calculator performs the comparison for your inputs. If the prices do not produce a useful break-even within your possible usage, compare the actual annual totals instead.
Cheap hours must match useful demand
Storage heating and hot-water storage can place substantial demand in a night window, but the controls and storage capacity matter. A home using most electricity during the evening may pay the higher day rate for those units. Check the exact schedule for the meter and tariff before setting timers; the separate Economy 7 times guide explains the verification steps.
Do not move appliance use to unsafe unattended hours solely to reduce the bill. Nor should you heat water or rooms unnecessarily just because the rate is low: cheaper extra use still costs money. Compare useful consumption that your household actually needs. If a daytime heating boost is necessary, include it rather than presenting a night-only estimate as the complete cost.
Economy 7 versus other time-of-use tariffs
Octopus Go, Cosy and Agile have their own structures and eligibility requirements. A dedicated EV window, several heat-pump-related periods or changing half-hourly prices are not the same product as seven-hour Economy 7. The existing tariff pages explain those differences. Confirm your equipment, meter and eligibility before treating any offer as an available alternative.
Compare the full pattern of rates against when you use electricity. A cheap rate for a short period does not establish the lowest annual cost, and a variable half-hourly product carries a different type of price uncertainty from a fixed day/night offer. This guide links to those pages without republishing rates that may be dated, regional or specific to a different product.
Check service and switching details
Price is not the only practical consideration. Check billing accuracy, support for your meter type, treatment of the two registers and the process if something goes wrong. PowerGuardian’s Supplier Monitor gives editorial service and transparency scores, not proof that a particular E7 tariff is the cheapest. Keep that evidence separate from your rate comparison.
Before switching, save the quote, confirm both registers and ask how the off-peak schedule will be maintained or changed. Read the “is Economy 7 worth it” article for the wider decision and use the calculator for the actual cost comparison. PowerGuardian may earn commission from clearly labelled partner links on linked pages; those arrangements do not determine the scores or make a tariff suitable for your home.