How Economy 7 works
An Economy 7 meter records electricity usage in two separate registers: a daytime rate and a night rate. The night rate applies for a continuous period of around seven hours (hence "Economy 7"), typically falling somewhere between 11pm and 8am, though the exact hours depend on your region and supplier; it's worth checking the specific times that apply to your meter, as they're not identical everywhere in the UK.
During the night-rate hours, electricity is charged at a significantly lower unit rate than during the day. In exchange, the daytime rate on an Economy 7 tariff is usually higher than the single unit rate you'd get on a standard (single-rate) tariff.
Who tends to benefit from Economy 7
Economy 7 was originally introduced alongside storage heaters, which use off-peak electricity overnight to heat ceramic bricks that then release warmth throughout the day. If your home has storage heaters, you're likely already on an Economy 7 (or similar) meter, since the heaters are designed around this charging pattern.
Beyond storage heaters, households that can shift a meaningful amount of their electricity use to nighttime hours may also benefit; for example, charging an electric vehicle overnight, running a washing machine, dishwasher, or tumble dryer on a timer overnight, or heating water via an immersion heater on a timer.
Who might not benefit
If most of your electricity use happens during the day; for example, if you work from home and use appliances, lighting, and heating mainly during daytime hours; the higher daytime rate on an Economy 7 tariff could leave you worse off than a single-rate tariff, even with cheap night electricity. Whether Economy 7 works out cheaper depends heavily on what proportion of your usage happens at night.
How to check if you're on Economy 7
If your electricity meter has two displays or two sets of digits (sometimes labelled "Normal" and "Low" or "Day" and "Night"), you likely have an Economy 7 (or similar two-rate) meter. Smart meters can also be configured for two-rate billing, and your in-home display or supplier app should show separate day and night figures if so. If you're unsure, your current supplier can confirm your meter type and tariff structure.
Switching tariffs with an Economy 7 meter
When comparing tariffs with an Economy 7 (or other two-rate) meter, you'll generally need separate usage figures for day and night electricity, since the unit rates differ for each. Your bills should show this breakdown if you're already on a two-rate tariff. Not every tariff on the market is structured for two-rate meters, so comparison results for Economy 7 households may show a more limited set of options than for single-rate meters; though dedicated Economy 7 tariffs are widely available from most major suppliers.
If you're considering moving away from storage heaters or changing how you use electricity (for example, switching to a different heating system), it's worth re-evaluating whether Economy 7 still suits your household, since the tariff only pays off if your usage pattern matches it.