What type of meter is used to bill energy consumed by electric storage heaters in a domestic premises?

• A. A digital smart meter
• B. A prepaid meter
• C. A mechanical meter
• D. An analogue day-and-night rate kWh meter

Answer: (D)

Electric storage heaters are charged on a two-rate tariff, with cheaper electricity at night and more at the day. To bill that correctly, the metering needs to capture how much energy is used in each time period. An analogue day-and-night rate meter provides exactly this: two registers that measure kWh for day and for night, allowing the supplier to apply the off-peak rate to the night usage. This dual-rate, often mechanical device was the standard way to bill storage-heater energy in domestic premises. While digital smart meters can also record time-based usage, the option describing the analogue dual-rate meter aligns with how storage heaters were traditionally billed.