How does the LED Lighting Savings Calculator work?
The calculator finds the wattage reduction per bulb, multiplies it by bulb count and operating time, converts the saved watt-hours to kWh, and applies your electricity rate. For a general watts-to-energy conversion, use the Watt to kWh Calculator.
Affiliate disclosure: As an Amazon Associate I earn from qualifying purchases.
For optional supporting equipment or reference material, you can browse Home energy reference books (paid link) on Amazon.com. Review practical energy concepts alongside actual bills and equipment documentation. A book does not replace a qualified electrical or heating-system assessment. No purchase is required to use this calculator.
What should you enter for old and LED wattage?
Use the actual wattage printed on the old and replacement bulbs or fixtures. Keep the number of bulbs and operating schedule consistent for a fair comparison. If you want to model a single appliance rather than a before-and-after lighting upgrade, use the Appliance Energy Cost Calculator.
What do annual kWh savings mean?
Annual kWh savings measure the reduction in modeled electrical energy from the lower wattage. The cost savings multiply that energy reduction by your entered rate. You can price any known kWh amount with the kWh Cost Calculator.
What is not included in the savings estimate?
The calculator focuses on electricity consumption. Purchase price, lamp life, maintenance, dimmer compatibility, light output, color quality and rebates are separate considerations. For total household spending, use the Home Energy Cost Calculator, and for a simple load cost use the Electricity Cost Calculator.
Worked example: LED Lighting Savings
Enter the following values in the LED Lighting Savings Calculator and calculate to reproduce this result.
- Old bulb wattage: 60
- LED bulb wattage: 9
- Number of bulbs: 10
- Hours used per day: 5
- Days used per year: 365
- Electricity rate: 0.18
Example result: $167.54. Reducing 10 bulbs from 60 W to 9 W saves about 930.75 kWh/year under the entered schedule.
Calculation used: annual savings = (old W − LED W) × bulbs × hours/day × days/year ÷ 1,000 × rate
How to interpret this example
Savings follow the wattage difference multiplied by the number of bulbs and their use. They are energy-cost savings, not automatically net savings after purchase or installation. Make sure old and replacement bulbs provide suitable light output for the comparison.
Frequently asked questions about LED Lighting Savings
Annual kWh saved = (old watts − LED watts) × bulbs × hours per day × days per year ÷ 1,000. Dollar savings equals kWh saved × electricity rate.
The tool is designed to estimate energy savings from a lower-wattage replacement. If the replacement uses equal or more power, there is no positive energy saving.
No. Compare light output and suitability, not wattage alone, when selecting a replacement.
No. It calculates electricity savings only.
Yes, if the old and new wattage values represent the complete fixture power draw being compared.
No. Lamp replacement and labor savings are not included.
Yes, provided the wattage, quantity and operating schedule are appropriate for the scenario.
Actual operating hours, controls, dimming, occupancy, electricity rates and fixture power can differ from the assumptions entered.
Sources and methodology
The calculator uses the transparent formula described on this page and the values you enter. These authoritative U.S. resources provide context for electricity, home energy, solar, efficiency or safety topics related to this tool.