Most household lights cost about $0.10-$1.35 per bulb each month, depending on wattage, daily use, and the local electricity rate. A 9-watt LED used for three hours a day typically costs around $0.13 monthly, while a 60-watt incandescent used the same way costs about $0.86 at an average rate of $0.16 per kilowatt-hour.
| Item | Low | Average | High | Notes |
|---|---|---|---|---|
| 9-watt LED, monthly | $0.10 | $0.13 | $0.20 | Three hours daily; $0.12-$0.25 per kWh |
| 60-watt incandescent, monthly | $0.65 | $0.86 | $1.35 | Three hours daily; same rate range |
| One 9-watt LED, yearly | $1.18 | $1.58 | $2.46 | About 1,095 hours per year |
| Ten 9-watt LEDs, monthly | $0.97 | $1.40 | $2.05 | Three hours daily at $0.12-$0.25 per kWh |
What one LED or incandescent bulb costs each month
At three hours of use per day, a typical 9-watt LED consumes about 0.81 kilowatt-hours (kWh) per month. At $0.16 per kWh, that works out to roughly $0.13. A 60-watt incandescent consumes 5.4 kWh for the same schedule, or about $0.86 at that rate.
For comparable light and run time, an incandescent can use roughly six to seven times as much electricity as an LED. The estimate covers energy only; it excludes the bulb purchase and any fixed utility fees. Assumptions: 30-day month, three hours of use daily, no dimmer losses, and electricity priced at $0.12-$0.25 per kWh.
How wattage and electricity rates shape the bill
Electric bills charge for energy use, not the number of bulbs. The basic calculation is watts ÷ 1,000 × hours used × electricity price per kWh. For example, a 10-watt bulb running five hours daily uses 1.5 kWh monthly. At $0.16 per kWh, it costs $0.24 a month.
Every extra 1,000 watts used for one hour adds 1 kWh to the bill. The utility’s energy rate may differ by season, time of day, or plan. Some bills also have fixed delivery charges, which generally do not change when a particular light is switched off.
What a room full of lights adds to monthly costs
For a quick estimate, multiply the per-bulb cost by the number of bulbs with similar wattage and schedules. Ten 9-watt LEDs used three hours daily consume about 8.1 kWh a month, costing around $1.30 at $0.16 per kWh. Ten 60-watt incandescent bulbs on that schedule use 54 kWh, or about $8.64.
| Lighting setup | Monthly energy | At $0.12 per kWh | At $0.16 per kWh | At $0.25 per kWh |
|---|---|---|---|---|
| One 9-watt LED, 3 hours daily | 0.81 kWh | $0.10 | $0.13 | $0.20 |
| One 60-watt incandescent, 3 hours daily | 5.4 kWh | $0.65 | $0.86 | $1.35 |
| Ten 9-watt LEDs, 3 hours daily | 8.1 kWh | $0.97 | $1.30 | $2.03 |
| Ten 60-watt incandescents, 3 hours daily | 54 kWh | $6.48 | $8.64 | $13.50 |
Why long hours and high-wattage fixtures cost more
Daily run time can matter as much as bulb type. A 9-watt LED left on for 10 hours daily uses about 2.7 kWh monthly, costing $0.32-$0.68 at rates of $0.12-$0.25 per kWh. A 100-watt bulb on the same schedule uses 30 kWh and costs $3.60-$7.50 monthly.
Check actual fixture wattage and hours before estimating a whole-house total. A fixture with several bulbs adds their wattages together. For example, a three-bulb fixture with 9-watt LEDs draws 27 watts, not 9 watts.
LED, CFL, and incandescent running costs compared
For three hours of daily use at $0.16 per kWh, a 9-watt LED costs about $1.58 a year. A typical 14-watt compact fluorescent (CFL) costs around $2.45, while a 60-watt incandescent costs about $10.51. Actual brightness and wattage vary, so compare the label’s lumens and watts rather than assuming every bulb produces identical light.
LEDs generally have the lowest ongoing energy expense among these common bulb types. Replacement prices and lifespans also affect total ownership cost, but energy savings alone may be modest for a bulb used only briefly each day.
Estimate lighting cost from the wattage label
Use this formula for a single bulb or fixture: . For monthly cost, use the total hours in the month; a bulb running four hours daily for 30 days runs 120 hours. A 12-watt LED at $0.18 per kWh then costs about $0.26 for the month.
Multiply the result by the number of bulbs only when their wattage and schedules match. For mixed rooms, calculate each group separately and add the results. The electricity price can be found on a utility bill, usually listed in cents per kWh or dollars per kWh.
Lower lighting bills by controlling hours and wattage
Replacing frequently used incandescent bulbs with equivalent-brightness LEDs can reduce energy use substantially. Turning off lights in empty rooms also helps, especially for higher-wattage bulbs or fixtures left on for many hours. Timers and occupancy sensors may reduce wasted run time, though their purchase price should be weighed against expected savings.
Start with bulbs used longest and fixtures with the highest combined wattage. Changing a seldom-used bulb may produce little bill reduction, while cutting two hours of daily use from several fixtures can add up over a year. Check dimmer compatibility before buying replacement LEDs.