How Much Electricity
Does a Light Bulb Use?
Light bulb electricity has changed enormously since LEDs replaced halogens. The honest UK 2026 figure for a typical LED bulb is 0.1p per hour. The same brightness on an old incandescent costs roughly 1.5p per hour, 15 times more.
A modern LED light bulb draws 5 to 15 watts depending on brightness. At the current Q2 2026 Ofgem unit rate of 24.7p per kWh that means 0.12p to 0.37p per hour. A halogen bulb of equivalent brightness draws 35 to 50W (0.86p to 1.24p per hour). An incandescent bulb (now rare) draws 60 to 100W (1.48p to 2.47p per hour). For a typical UK home with 25 to 35 bulbs running an average of 4 hours daily, switching from halogen to LED saves £60 to £120 per year on lighting alone.
The figures that matter
LED equivalent
Replacing 40 to 100W incandescent or 35 to 70W halogen brightness.
Halogen
Pre-2018 standard. Now restricted in UK but still in use in many homes.
Incandescent
Pre-2009 traditional bulbs. Banned in UK retail since 2009 plus rarely seen now.
Typical LED
Cost per hour for a typical 8 to 10W LED bulb at 24.7p per kWh.
Four things to consider
LED uses 80%+ less
An LED bulb uses around 15 to 20 percent of the electricity of an equivalent-brightness halogen.
Lifespan is 15 to 25x longer
LEDs last 15,000 to 50,000 hours. Halogens last 1,000 to 2,000 hours. Incandescents last 750 to 1,000 hours.
Lumens, not watts, measure brightness
Compare bulbs by lumens. 800 lumens equals roughly 60W incandescent or 8 to 10W LED.
Smart bulbs draw a tiny standby
Wi-Fi or Zigbee smart bulbs draw 0.5 to 1W in standby. Negligible per bulb but cumulative.
Real UK light bulb running costs by type
UK domestic lighting has shifted dramatically over the past 15 years. Incandescent bulbs were banned from sale in 2009. Halogen bulbs were restricted in 2018. LED bulbs are now the default for almost all new fittings. The transition has cut typical UK household lighting electricity by 60 to 80 percent.
Real numbers at 24.7p per kWh (Q2 2026 Ofgem cap):
- 5W LED (40W incandescent equivalent), 4 hrs daily: 0.02 kWh per day. 7.3 kWh per year. Roughly £1.80 per year per bulb.
- 10W LED (60W incandescent equivalent), 4 hrs daily: 0.04 kWh per day. 14.6 kWh per year. Roughly £3.61 per year per bulb.
- 15W LED (100W incandescent equivalent), 4 hrs daily: 0.06 kWh per day. 21.9 kWh per year. Roughly £5.41 per year per bulb.
- 40W halogen replacement (35W actual), 4 hrs daily: 0.14 kWh per day. 51 kWh per year. Roughly £12.62 per year per bulb.
- 60W incandescent (now rare), 4 hrs daily: 0.24 kWh per day. 87.6 kWh per year. Roughly £21.66 per year per bulb.
- UK home with 30 bulbs at 10W LED average, 4 hrs daily: 438 kWh per year. Roughly £108 per year total.
- Same UK home with 30 bulbs at 50W halogen, 4 hrs daily: 2,190 kWh per year. Roughly £541 per year total.
Why LEDs are so much cheaper. Old incandescent bulbs heated a tungsten filament until it glowed. Around 90 percent of the electricity went on heat plus 10 percent on light. Halogens were similar with slightly better efficiency. LEDs use semiconductor junction emission which produces light directly with very little waste heat. The efficiency gap is roughly 8 to 10 times in light output per watt.
What to look for when buying replacement bulbs:
- Lumens for brightness. 800 lumens equals 60W incandescent. 1,500 lumens equals 100W incandescent. Watts only matter for running cost.
- Colour temperature. 2,700K is warm white (similar to incandescent). 4,000K is neutral. 6,500K is daylight. Choose based on room use.
- Dimmable rating. Not all LEDs work with dimmers. Check the box plus your existing dimmer compatibility.
- Lifespan rating. Premium LEDs last 25,000 to 50,000 hours. Budget LEDs claim 15,000 hours but often fail earlier.
- Smart features. Wi-Fi or Zigbee. Adds 0.5 to 1W standby per bulb but enables remote control plus scheduling.
Real number ranges
Annual cost per bulb (4 hrs daily UK use)
Light bulb use through a typical UK day
Brief use
Bathroom plus kitchen lights for 30 to 60 minutes. Brief overall daily contribution.
Mostly off
Daylight covers most rooms. Lights off during summer plus most of spring or autumn daytime.
Peak use
Most bulbs on for 3 to 5 hours through evening. Bulk of daily lighting electricity here.
Bedside plus hall
1 to 2 bulbs briefly. Daily total household lighting 1.2 to 2 kWh on LED, 5 to 8 kWh on halogen.
Four ways to cut lighting running costs
Replace any remaining halogens
LED replacement pays back in 1 to 2 years through running cost saving. Each halogen costs roughly £10 per year more than LED equivalent.
Use the lowest brightness needed
Most rooms are over-lit. Dimmable LEDs at 60 to 70 percent brightness use proportionally less electricity plus extend bulb life.
Switch off when leaving rooms
Old advice still applies. LEDs cycle on/off without affecting lifespan. Always switch off unused rooms.
Use motion sensors in low-traffic areas
Hallways, garages plus utility rooms benefit from motion-sensor switches. Lights only run when needed.
Compare the options
10W LED bulb
- ✓10W draw for 800 to 1000 lumens output.
- ✓0.25p per hour at 24.7p per kWh.
- ✓15,000 to 50,000 hour lifespan.
- ✓£3 to £4 per year at 4 hrs daily use.
- ✓Available in warm, neutral plus daylight colours.
50W halogen bulb
- ✗50W draw for similar lumens output.
- ✗1.24p per hour at the same Ofgem rate.
- ✗1,000 to 2,000 hour lifespan. Replaced 15 to 25x more often.
- ✗£11 to £13 per year at the same daily use.
- ✗Mostly warm white only. Limited colour options.
Lighting is one of the most successful UK efficiency wins of the past 15 years. Our full Appliances hub covers running costs across every major UK household appliance.
Visit the Appliances Hub
This article is one chapter inside our complete Appliances knowledge base. The hub covers running costs across every major household appliance from kettles to heat pumps.
More on appliance running costs
Three further everyday appliance articles in the same hub group cover related questions. The first is how much electricity does a house use per day uk for the household total context. The second covers how much electric does a tv use for related living room loads. The third is how much electric does a tv on standby use for related phantom loads.