A light typically costs less than a few cents per hour to run, but the yearly bill depends on bulb wattage, hours of use, and the electricity rate. At a planning rate of 16 cents per kilowatt-hour, a 9-watt LED used three hours daily costs about $1.58 a year, while a 60-watt incandescent used the same way costs about $10.51.
The figures below cover electricity use only, not the purchase price of a bulb, fixture, or smart control. Assumptions: U.S. residential electricity rates commonly vary by provider and location; examples use $0.12-$0.30 per kWh unless noted.
| Item | Low | Average | High | Notes |
|---|---|---|---|---|
| 9-watt LED, 3 hours daily | $1.18/year | $1.58/year | $2.96/year | Uses $0.12-$0.30 per kWh |
| 10-watt LED, 5 hours daily | $2.19/year | $2.92/year | $5.48/year | Approximate annual electricity cost |
| 60-watt incandescent, 3 hours daily | $8.76/year | $10.51/year | $19.71/year | Higher use than a comparable LED |
| Light running cost per hour | $0.001-$0.007 | $0.002-$0.003 | $0.018 | Depends on wattage and electricity rate |
What a 9-Watt LED Costs to Run Each Year
For a typical household LED, the electricity charge is usually only a few dollars per year. A 9-watt bulb running three hours daily consumes about 9.86 kilowatt-hours (kWh) annually. At $0.16 per kWh, that usage costs about $1.58; leaving it on for eight hours daily raises the annual cost to about $4.20 at the same rate.
A useful estimate is watts ÷ 1,000 × hours used × electricity price per kWh. For example, a 9-watt bulb used for four hours each day costs about $2.10 per year at $0.16 per kWh: 0.009 kW × 1,460 hours × $0.16. The number of bulbs matters: ten identical lights used on that schedule would cost roughly $21 annually.
Actual bills may include fixed service charges and taxes that are not caused by one bulb. For a small lighting calculation, use the energy charge on the bill rather than dividing the entire bill by household kWh, unless the goal is to estimate the full blended rate. For most frequently used household lights, bulb wattage and hours—not the fixture itself—drive the running cost.
How Bulb Wattage Turns Into the Electric Bill
Wattage measures the power a light uses while switched on; kWh measures that use over time. A 10-watt LED running for 100 hours uses 1 kWh. At $0.16 per kWh, those 100 hours cost 16 cents. A 60-watt bulb needs six times as much energy for the same duration, so it costs about 96 cents for 100 hours at that rate.
The table compares common bulb types at the same 800-lumen brightness, approximately the output of a traditional 60-watt incandescent. Actual wattage varies by model, and package labels show the specific figure to use.
| Bulb type and assumed wattage | Cost per 100 hours | Cost at 3 hours daily | Annual use |
|---|---|---|---|
| LED, 9 watts | $0.11-$0.27 | $1.18-$2.96 | 9.86 kWh |
| CFL, 14 watts | $0.17-$0.42 | $1.84-$4.60 | 15.33 kWh |
| Incandescent, 60 watts | $0.72-$1.80 | $7.88-$19.71 | 65.70 kWh |
| Halogen, 43 watts | $0.52-$1.29 | $5.65-$14.10 | 47.05 kWh |
For an itemized estimate, multiply kWh by the energy rate. At equal brightness, a 9-watt LED uses about 85% less electricity than a 60-watt incandescent.
How Hours and Electricity Rates Change the Total
Two identical bulbs can produce different bills if one runs in a hallway for an hour a day and the other illuminates a kitchen for six hours. Likewise, a household paying $0.30 per kWh pays 2.5 times as much for the same lighting use as one paying $0.12. Check the bill for the per-kWh energy charge, and account for time-of-use pricing if electricity costs more during specific hours.
For one 9-watt LED, the following annual estimates illustrate the effect of use and rate. These totals exclude taxes, fixed monthly charges, and any separate delivery charges tied to consumption.
| Daily use | At $0.12/kWh | At $0.16/kWh | At $0.30/kWh |
|---|---|---|---|
| 1 hour | $0.39/year | $0.53/year | $0.99/year |
| 3 hours | $1.18/year | $1.58/year | $2.96/year |
| 8 hours | $3.15/year | $4.20/year | $7.88/year |
| 24 hours | $9.46/year | $12.61/year | $23.65/year |
For several lights, calculate each wattage and schedule separately, then add the results. A porch bulb left on overnight may use more energy annually than a living-room light switched on briefly, even if both have the same wattage. Daily run time can matter as much as the electricity rate when comparing a home’s lighting expenses.
LED, CFL, and Incandescent Running Costs Compared
LEDs generally have the lowest running cost among common household bulbs because they produce similar brightness at much lower wattage. CFLs also use less energy than incandescents, though many households now choose LEDs when replacing them. The table above assumes matching brightness, but dimmer or brighter bulbs will change the comparison.
Purchase price is separate from electricity cost. A basic LED may cost roughly $2-$8 per bulb, while specialty, decorative, or connected models may cost $8-$25 or more. A standard incandescent may be less expensive upfront where still available, but frequent use can erase that initial price difference through higher energy consumption and more frequent replacement.
Bulb life, dimmer compatibility, color temperature, and enclosed-fixture ratings affect whether a product suits a particular socket. A bulb that flickers, overheats, or fails early can make the apparent savings less useful. Match the bulb’s base and rating to the fixture, and compare lumens rather than relying only on “equivalent watts.” The fair comparison is total ownership cost: purchase price plus electricity and replacement needs over the time the bulb is used.
What Three Common Lighting Setups Cost
These examples use $0.16 per kWh and show the approximate annual electricity expense, not bulb or fixture prices. They illustrate why a small difference in wattage becomes more meaningful when multiple lights operate for many hours.
| Lighting setup | Assumed use | Annual energy | Annual cost |
|---|---|---|---|
| One 9-watt bedroom LED | 3 hours daily | 9.86 kWh | $1.58 |
| Six 10-watt kitchen LEDs | 5 hours daily | 109.50 kWh | $17.52 |
| Four 60-watt incandescent bulbs | 4 hours daily | 350.40 kWh | $56.06 |
In the kitchen example, replacing six 60-watt incandescent bulbs with 10-watt LEDs would cut estimated annual energy use from 657 kWh to 109.5 kWh. At $0.16 per kWh, the electricity difference is about $87.60 per year, before considering the cost of buying replacement bulbs. The real savings depend on how often the lights are on and the household’s actual rate.
For a more specific estimate, record the wattage printed on each bulb, the number of bulbs in each fixture, and a typical daily schedule. A week of observation may be more accurate than assuming every light runs the same number of hours. Multi-bulb fixtures and long operating schedules make replacement decisions more consequential.
Why U.S. Power Rates Change Light-Bulb Costs
Residential rates vary across states and utility territories, so the same bulb does not have one fixed national running price. For practical budgeting, a range of $0.12-$0.30 per kWh covers many common residential scenarios, but a local bill may fall outside it. The summary table and examples use these rates to show how the estimate shifts.
At $0.12 per kWh, a 9-watt LED used three hours daily costs about $1.18 per year; at $0.30, it costs about $2.96. A 60-watt incandescent on the same schedule costs about $7.88-$19.71. The difference between low- and high-rate locations becomes larger as wattage and hours increase.
Some bills have time-of-use plans, seasonal adjustments, or separate supply and delivery charges. If a utility charges different energy prices by time of day, use the rate that applies during the light’s operating hours or calculate separate periods. Fixed monthly account fees normally do not change when one bulb is switched off, so they should not be counted as a direct savings from that bulb.
Use the rate and billing structure on the household’s own electric bill for the closest estimate. A utility’s average bill amount is not a substitute for the per-kWh charge when estimating a specific light.
Do Smart Bulbs or Dimmers Lower the Bill?
A dimmer can reduce energy use when it actually lowers a compatible bulb’s output, but the savings depend on how far and how often the light is dimmed. A smart bulb may help reduce wasted hours through schedules, occupancy routines, or remote shutoff; its connectivity can also draw a small amount of standby power. Follow the manufacturer’s compatibility guidance for dimmers and fixtures.
Simple controls may cost less to install than replacing a whole lighting system. A basic plug-in timer or sensor can range from about $8-$30, while smart switches and dimmers often cost roughly $20-$80 for the device, before installation. A hardwired control may add electrician labor, commonly around $75-$150 per hour, with minimum service charges varying by market and job.
Controls are most likely to affect bills where lights are regularly left on for long periods. A smart device is unlikely to pay for itself through energy savings on a single 9-watt bulb used only briefly. For a porch, garage, or multi-light room with frequent unnecessary run time, an automatic shutoff can offer more practical savings.
Estimate the avoided operating hours before buying controls, and compare that value with the equipment and installation price. Device standby use, compatibility, and any required hub should be included in the cost comparison.
How to Cut Lighting Costs Without Sacrificing Use
Replacing high-use incandescent or halogen bulbs with LEDs is usually the clearest way to reduce electricity use without changing how a room is lit. Start with bulbs used several hours per day, especially in kitchens, living rooms, and exterior fixtures. Match brightness by lumens, check whether the bulb is rated for an enclosed fixture, and avoid buying a higher-wattage product than the fixture allows.
Controlling run time can also help. Turn off lights in unoccupied rooms, use a timer for predictable schedules, or consider a motion sensor where lights are often forgotten. These steps save little if the bulb is already used briefly, so target the rooms with the longest schedules first.
Compare bulb prices alongside expected use. If an LED costs several dollars more than a basic alternative, estimate its yearly energy savings using the wattage difference and local rate. For example, replacing one 60-watt incandescent with a 9-watt LED saves about 55.8 kWh per year at three hours daily, worth roughly $6.70-$16.74 at $0.12-$0.30 per kWh. A high-use bulb can recover the purchase difference faster than one switched on occasionally.
Do not replace functioning fixtures simply to lower the cost of a single bulb unless the fixture is inefficient, incompatible, or due for replacement. Prioritize high-wattage bulbs with long daily use, then choose a compatible LED and control the hours it runs.