Free UK tool
LED Bulb Savings Calculator
Still running halogens, old incandescents or sluggish CFLs? Count what's actually in your fittings, set your electricity rate, and see what a full LED swap would save you per year — and how many months until the new bulbs pay for themselves.
Wondering whether LED bulbs are worth it in the UK at 2026 energy prices? This free calculator compares your existing bulbs against their LED equivalents at your real unit rate. For most homes with halogen spotlights, the answer lands between £30 and £120 a year — often with a payback of under six months.
Wattages are typical values from manufacturer specifications and published energy research — not our own bench measurements. LED bulb cost assumes roughly £3.00 per bulb.
On your bill or in your supplier's app. The default is a typical UK capped rate.
Kitchens and hallways are usually "high"; bedrooms are usually "low".
50 W halogen spotlight (GU10)
→ 4.5 W LED · The worst offender in most kitchens and hallways
£97.65
saved per year
35 W halogen spotlight
→ 4 W LED · Common in bathrooms and under-cabinet strips
—
saved per year
60 W incandescent GLS
→ 8 W LED · Older pendant and table-lamp bulbs
—
saved per year
40 W incandescent candle / golf ball
→ 5 W LED · Chandeliers, wall lights and bedside lamps
—
saved per year
20 W CFL (old energy-saver)
→ 8 W LED · Slow-start spirals from the 2000s
—
saved per year
11 W CFL
→ 5 W LED · Small CFLs in hallways and porches
—
saved per year
40 W decorative filament
→ 4 W LED · Exposed Edison-style bulbs — LED filaments look identical
—
saved per year
Your LED swap, in pounds
£97.65
saved per year at 24.5p/kWh
£18.00
to swap 6 bulbs to LED
2.2 mo
until the bulbs pay you back
Where the biggest win is
50 W halogen spotlight (GU10) — each one you swap saves about £16.28 a year, so start there.
How the maths works
Each bulb's annual energy use is watts × hours per day × 365 ÷ 1,000. We work that out for your existing bulb and for its LED equivalent, multiply the difference by your unit rate, and add it up across the house. A single 50 W halogen used four hours a day costs about £17.89 a year at your rate — its LED replacement costs about £1.61.
Two honest caveats. First, LEDs last 10–15 times longer than halogens, so the saving above actually understates things — we've ignored replacement bulb costs entirely. Second, usage varies by room, so if you know a fitting is on all evening, count it under "high" and put rarely-used rooms under "low" for a sharper estimate.
Common questions
How much can a UK home save switching to LED bulbs?
Most UK homes with halogen spotlights save between £30 and £120 a year by going fully LED. Homes with lots of GU10 downlights — kitchens and hallways especially — land at the top of that range, because a room of ten 50 W halogens is a 500 W heater that happens to make light.
Are smart bulbs worth it, or should I just buy plain LEDs?
For pure savings, plain LEDs win — they're a fraction of the price and use the same tiny amount of power. Smart bulbs are worth the premium in rooms where dimming, schedules or warm-to-cool colour actually change how you live: bedrooms, living rooms and home offices.
Do LED bulbs really last 15,000 hours?
Rated lifetimes of 15,000–25,000 hours are common on the box and broadly hold up in independent testing of reputable brands. At four hours a day that's ten years or more. Cheap unbranded bulbs are the exception — stick to known names and the rated life is realistic.
Can I put LED bulbs in dimmer switches and enclosed fittings?
Yes, but buy bulbs labelled "dimmable" for dimmer circuits — old leading-edge dimmers can make non-dimmable LEDs flicker. For fully enclosed fittings, check the bulb is rated for enclosed use, as heat shortens LED lifespan.