Cost to run an LED downlight
An LED downlight drawing 13 W costs 0.34p for each hour of running at 26.32p/kWh. Used 4 hours a day, every day, that comes to 41.6p a month.
An hour of running costs
0.34p an hour
That is 0.013 kWh. Used as set, it comes to 41.6p a month and £5.00 a year.
On the label or in the manual.
Standby, thermostats and off-peak use
A thermostat switches it on and off to hold a temperature. 100% if it runs flat out.
Drawn while plugged in and not running.
| Period | Cost | Energy | CO2e |
|---|---|---|---|
| An hour of running | 0.34p | 0.013 kWh | 2.8 g |
| A day, on average | 1.37p | 0.052 kWh | 11 g |
| A month | 41.6p | 1.58 kWh | 344 g |
| A year | £5.00 | 19.0 kWh | 4.1 kg |
How we calculated this
Energy is power multiplied by time: 13 W running for an hour uses 0.013 kWh.
The figures are for ENERGY STAR certified models sold in the US and Canada. Certified models are more efficient than the average model on sale, and many are larger than the ones sold in Europe, so an older or less efficient one will use more. Power rises with brightness: the median certified downlight gives 1,150 lumens. Bulbs and other kinds of light are not covered by this data.
The starting use for an LED downlight, 4 hours a day, every day, is where the calculator starts, not a measurement of your home: change it to how you use yours. A day is the average across the week, and a month is a twelfth of a 365-day year.
Electricity costs 26.32p/kWh. That is the published figure for the United Kingdom, 1 Oct – 31 Dec 2026, from Ofgem. Average for England, Scotland and Wales, paying by Direct Debit. No VAT on electricity from 1 October 2026 to 31 March 2027.
Standing charges are left out: you pay them whether or not the appliance runs.
Emissions use 0.217 kg CO2e per kWh, the lifecycle intensity of electricity generated in the United Kingdom in 2025, from Ember, via Our World in Data. Lifecycle means building the power stations and supplying their fuel are counted too. It is the grid’s average, not the particular power station an extra appliance brings on.
What drives the cost
An LED downlight gives a lot of light for very little power: across 3,570 certified indoor downlights the median draws 13 W for 1,150 lumens, so an hour costs a fraction of a penny or cent, and at 4 hours a day, every day, an LED downlight costs £5.00 a year at 26.32p/kWh.
Also called: recessed light, spotlight, ceiling light, downlighter, LED light fitting.
What it costs in the UK, Europe and the US
For an LED downlight used as typical (4 hours a day, every day), at each country’s published average electricity price.
| Country | Electricity price | An hour |
|---|---|---|
| United Kingdom | 26.32p/kWh | 0.34p |
| United States (average) | 18.19¢/kWh | 0.24¢ |
| Ireland | €0.4042/kWh | €0.0053 |
| Germany | 0,3869 €/kWh | 0,005 € |
| France | 0,2561 €/kWh | 0,0033 € |
| Spain | 0,2669 €/kWh | 0,0035 € |
| Italy | 0,2966 €/kWh | 0,0039 € |
| Netherlands | € 0,2558/kWh | € 0,0033 |
How to spend less on it
- Fit LEDs wherever a light is on for hours: the saving over an old incandescent or halogen bulb is largest where it is used most.
- Turn lights off when you leave a room: an LED costs little, but a house of them left on adds up.
- Choose the brightness you need: a fitting that gives more light than the room needs draws more than it has to.
Questions
How much does an LED downlight cost to run per hour?
At 26.32p/kWh, an LED downlight drawing 13 W costs 0.34p for every hour of running at full power.
How much does an LED downlight cost to run a year?
Used 4 hours a day, every day, it costs about £5.00 a year at 26.32p/kWh, or 41.6p a month.
How many watts does an LED downlight use?
Most draw between 8 W and 32.7 W while running, and 13 W is typical. The rating is on the label or in the manual.
How much does an LED downlight cost to run?
A typical certified downlight draws 13 W, so an hour costs 0.34p at 26.32p/kWh. If you leave a whole room of them on for a full day, the cost is the number of lights times 1.37p.
Does a dimmer save energy?
A dimmable LED draws less when it is dimmed, so dimming saves some energy, though not in proportion to the light you give up.
Sources
- ENERGY STAR Certified Light Fixtures - Downlights (open data), ENERGY STAR, US Environmental Protection Agency, 26 September 2026. “ENERGY STAR certified indoor downlights, input power: median 13 W across 3,570 certified models, 10th to 90th percentile 8 W to 32.7 W (models where indoor_outdoor='Indoor').”
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