Energy & cost
LED energy savings calculator
Compare running energy and cost for two sets of lights.
Result
LED energy savingsReady
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Enter your values and press Calculate result.Formula
Saved kWh = (old W − new W) × quantity × hours × days ÷ 1,000Within this model
Equal numbers of lamps with identical operating hours and constant input powers. Compare equivalent useful light output separately. Includes only energy charges; excludes purchase, installation, maintenance and changes in heating demand.
What the numbers mean
This compares the energy consumed by the two sets of lights. Use the whole fitting’s electrical input power, including its driver or ballast where applicable. A negative saving means the new lights use more energy under the entered conditions.
Formula reference: Virginia Tech · Estimating energy use ↗A worked example
(60 W − 8 W) × 10 lamps × 4 hours × 30 days ÷ 1,000 = 62.4 kWh saved. At 25 p/kWh, that is £15.60.
Validation, precision and limitations