LED Bulb Savings Calculator
Money, energy and COโ saved by switching to LED, with payback.
About this tool
Enter how many bulbs you're replacing, the old and new wattages, hours of use per day, your electricity price and bulb prices. The tool shows yearly savings, energy and COโ saved, payback time, how long the LEDs will last and the lifetime saving.
Why LEDs pay back quickly
LEDs use around 80โ90% less electricity than incandescent bulbs for the same light, and last about 15,000โ25,000 hours instead of 1,000. The yearly energy saved is bulbs ร (old watts โ new watts) ร hours per day ร 365 รท 1,000 kWh. Replace ten 60 W bulbs with 8.5 W LEDs used four hours a day and you save about 750 kWh a year: around ยฃ188 at 25p per kWh, or $120 at 16ยข. LEDs costing ยฃ3 each pay for themselves in about two months. At that use they last about ten years, avoiding around 140 replacement incandescent bulbs. The COโ saving depends on your grid's carbon intensity: about 0.2 kg per kWh in the UK, around 0.4 in the US, higher in coal-heavy grids. Honest limits: savings are smaller when replacing halogens or CFLs or for lights that are rarely on. Cheap LEDs, or fittings that trap heat, may not reach their rated life. Not financial advice. The light bulb lumens calculator and the solar panel calculator are related.
Frequently asked questions
How much do LED bulbs save?
About 80 to 90% of lighting energy compared with incandescent bulbs, often ยฃ15 to ยฃ20 per bulb per year for heavily used lights.
How long do LED bulbs take to pay back?
Usually a few months when replacing incandescent bulbs used several hours a day.
How long do LED bulbs last?
Typically 15,000 to 25,000 hours, about 10 to 17 years at 4 hours a day.
Is it worth replacing CFLs with LEDs?
The saving is smaller (CFLs are already efficient), so many people replace CFLs as they fail.
Is my data sent anywhere?
No. Everything is calculated in your browser, and nothing is stored or sent.