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Incandescent to LED Savings

Quickly estimate how much you can save on yearly electricity and CO2 by replacing incandescent bulbs with LED or fluorescent lamps, based on wattage, hours of use, and the number of bulbs.

Input

Estimate the yearly electricity cost and CO2 savings from swapping incandescent bulbs for lower-wattage LED or fluorescent lamps. The unit price and emission factor can be adjusted to match your situation.

W
W
hrs
bulbs
$/kWh
kg-CO2/kWh

Result

Yearly savings

$7,977.08

Yearly CO2 reduction

115.8 kg

Yearly cost before

$9,165.15

Yearly cost after

$1,188.08

Before vs. after (totals)

ItemBeforeAfter
Yearly energy use295.7 kWh38.3 kWh
Yearly electricity cost$9,165.15$1,188.08
Yearly CO2 emissions133.0 kg17.2 kg

How it works

  • Yearly electricity cost is figured as wattage (W) / 1000 x hours lit per day x 365 days x electricity rate x number of bulbs. The before and after cases use the same hours and bulb count, and the difference is shown as the yearly savings.
  • CO2 emissions are calculated as yearly energy use (kWh) x CO2 emission factor (kg-CO2/kWh). The default factor of 0.45 kg-CO2/kWh is a representative grid average, but it varies by country, utility, and energy mix, so you can change it in the input field.
  • Electricity rates differ widely by country and provider, and the default rate as well as the sample wattages (such as 54 W incandescent and 7 W LED) are only examples. Enter the figures from your own bulb specs and electricity bill for a more accurate estimate.
  • Enter hours lit per day as greater than 0 and 24 or less, and the number of bulbs as 1 or more. Lights that stay on longer or fixtures with more bulbs see the largest savings from switching.
  • Results are approximate. Bulb aging, dimming, switching frequency, seasonal changes in usage, and tiered electricity pricing are not reflected, so treat the figures as a guideline.