What is the LED Savings Calculator?
The LED Savings Calculator estimates how much money you can save on your electricity bill by replacing traditional incandescent or halogen light bulbs with energy-efficient LEDs. LEDs use a fraction of the power to produce the same amount of light, so over a year — and especially over a decade — the difference adds up significantly.
How to use it
Enter the wattage of your current bulbs, the wattage of the LED replacements, how many hours per day the lights are on, the number of bulbs, and your local electricity price per kilowatt-hour (kWh). The calculator shows your annual savings, energy saved in kWh, the running cost of each option, and your projected 10-year savings.
The formula explained
The wattage difference between the old and LED bulbs is divided by 1000 to convert watts to kilowatts. Multiplying by hours per day and 365 days gives annual kilowatt-hours per bulb, and multiplying by the number of bulbs and your electricity price yields total yearly savings:
$$\text{Annual savings} = \frac{\text{old W} - \text{LED W}}{1000} \times \text{hours/day} \times 365 \times \text{price per kWh} \times \text{bulbs}$$
Worked example
Suppose you replace ten 60 W incandescent bulbs with 10 W LEDs, used 5 hours a day, with electricity at $0.15/kWh. Watts saved = 50 W. Annual kWh = \((50/1000) \times 5 \times 365 \times 10 = 912.5\) kWh. Annual savings = \(912.5 \times \$0.15 =\) $136.88. Over 10 years that is about $1,368.
FAQ
Does this include bulb purchase cost? No — it estimates energy savings only. LEDs also last far longer, adding extra savings on replacements.
What price should I use? Use the per-kWh rate from your electricity bill (often $0.10–$0.30 in the US, varies elsewhere).
Are LED wattages lower than they look? Yes. A 9–12 W LED typically replaces a 60 W incandescent bulb at the same brightness.
