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Guide
At Ofgem’s 26.32p/kWh average direct-debit rate for October–December 2026, a constant 16 W load costs about 10.1p a day; a constant 20 W load costs about 12.6p.
Convert watts to kilowatts, multiply by hours used, then multiply by your unit price. Formula: watts ÷ 1,000 × hours × pence per kWh. Ofgem lists an average direct-debit electricity unit rate of 26.32p/kWh for England, Scotland and Wales from 1 October to 31 December 2026.
At 26.32p/kWh, a constant 16 W load uses 0.384 kWh/day and costs about 10.1p/day or £36.89/year. A constant 20 W load uses 0.48 kWh/day and costs about 12.6p/day or £46.11/year. WINIX publishes a 12–55 W range; if held constantly at those endpoints, the examples are about 7.6p to 34.7p/day.
Longer runtime filters more air, but automatic mode or a lower setting may reduce power and airflow. Use the mode that achieves the air changes you need without assuming the maximum wattage runs continuously.
Follow the product instructions and your household safety preferences. If the room is unoccupied for long periods, schedule operation around when filtration is useful rather than treating 24/7 as mandatory.
Electricity is only one part. Add current filter price multiplied by replacements per year. Because filter prices change, Gearjury does not show a yearly filter total without a dated retail source.
Common questions
Many small models publish wattages below larger household appliances, but cost depends on power and runtime. Use watts × hours × your tariff.
At 26.32p/kWh, a constant 20 W load for 24 hours is about 12.6p. Your tariff and actual duty cycle may differ.
Longer runtime filters more air, but it is not automatically necessary. Match runtime and fan speed to the room, source and manufacturer guidance.
It may lower fan speed when the sensor reports cleaner air, but savings depend on the model and conditions. Use measured consumption for a precise figure.
Keep exploring
Compare five air purifiers by published noise, room coverage and CADR. Philips AC0820/10 has the lowest stated sleep-mode figure in this source pack; other models suit different room and control needs.
Philips AC0820/10 leads with a 19 dB(A) sleep mode in manufacturer data. Levoit, Blueair and Winix cover other bedroom needs, from small rooms to larger spaces.
Learn how to choose an air purifier by room volume, CADR, filtration, noise and upkeep, including what size air purifier you need.
Compare air purifiers for UK homes by room size, noise and upkeep, then choose the buying guide, shortlist or model comparison that fits your decision.