How Much Does 1 Light Bulb Cost Per Year?
Uncover the actual yearly cost of your light bulbs. Understand their financial impact and how smart choices can save you money.
The annual operating cost of a light bulb is a financial consideration for homeowners. While the initial purchase price is visible, the ongoing expense of its electricity consumption often goes unnoticed. Understanding how to calculate this recurring cost allows individuals to make informed decisions about their lighting choices, potentially leading to long-term savings.
Calculating Electricity Consumption
Electricity consumption is measured in kilowatt-hours (kWh), the unit for utility billing. To determine a light bulb’s annual electricity usage, identify its power rating in watts (W), found on the bulb or packaging. This wattage indicates the rate at which the bulb consumes energy.
The calculation also requires knowing the number of hours the light bulb operates each day. For residential settings, a common estimate for daily light bulb usage is 3 hours. To convert wattage and daily usage into annual kilowatt-hours, multiply the bulb’s wattage by the hours it is used per day, then by 365 days, and finally divide the result by 1,000 to convert watt-hours into kilowatt-hours. For instance, a 60-watt incandescent light bulb used for 3 hours daily consumes approximately 65.7 kilowatt-hours annually (60 Watts 3 hours/day 365 days/year / 1,000 = 65.7 kWh).
Understanding Electricity Costs
Once the annual electricity consumption in kilowatt-hours (kWh) for a light bulb is determined, apply the prevailing electricity rate. Electricity rates are expressed in cents or dollars per kilowatt-hour and can be found on a monthly utility bill or the utility provider’s website. These rates represent the price charged for each unit of electricity consumed.
The average residential electricity rate in the United States was approximately 17.47 cents per kilowatt-hour as of August 2025, though these rates can fluctuate by region and market conditions. To calculate the annual cost of operating a light bulb, the total annual kilowatt-hours consumed is multiplied by the per-kilowatt-hour rate. For example, if a light bulb uses 65.7 kWh annually and the electricity rate is $0.1747 per kWh, the yearly operating cost would be approximately $11.48 (65.7 kWh $0.1747/kWh).
Comparing Bulb Types
The type of light bulb significantly influences its annual operating cost due to varying energy efficiencies. Historically, incandescent bulbs were prevalent, with a typical 60-watt bulb serving as a common reference for brightness. Compared to incandescents, Compact Fluorescent Lamps (CFLs) offer a more energy-efficient alternative, consuming about 14 watts to produce a similar amount of light. Light Emitting Diodes (LEDs) represent the most efficient option, requiring only about 9 watts to achieve brightness equivalent to a 60-watt incandescent bulb.
Considering a light bulb used for 3 hours per day and an electricity rate of 17.47 cents per kWh, the cost differences become clear. A 60-watt incandescent bulb would cost approximately $11.48 per year to operate. In contrast, a 14-watt CFL bulb, providing similar light output, would cost about $2.68 annually. The most savings come from 9-watt LED bulbs, which cost roughly $1.72 per year for electricity. These comparisons highlight that while LEDs and CFLs may have a higher initial purchase price than incandescents, their lower energy consumption translates into long-term cost savings over their lifespan, which can range from 8,000 hours for CFLs to over 25,000 hours for LEDs, far exceeding the 1,000-hour lifespan of incandescent bulbs.