Light Bulb Savings Calculator

Switching to LED bulbs is one of the simplest and most effective ways to reduce household energy costs. LED bulbs use 75-80% less electricity than traditional incandescent bulbs and last 15-25 times longer, making them a clear financial winner.

The savings calculation: Annual Energy Cost = (Wattage / 1000) × Hours per Day × 365 × Electricity Rate Annual Savings per Bulb = Incandescent Cost - LED Cost Total Annual Savings = Savings per Bulb × Number of Bulbs

Bulb type comparison (equivalent to 60-watt incandescent):

• Incandescent: 60 watts, ~1,000 hour lifespan, ~$0.50 per bulb
• CFL (compact fluorescent): 13 watts, ~8,000 hour lifespan, ~$2.00 per bulb
• LED: 9 watts, ~25,000 hour lifespan, ~$2.50 per bulb

Brightness equivalents (measured in lumens): Lumens measure actual light output, while watts measure energy consumed. The same brightness requires very different wattages:

• 450 lumens (40W equivalent): Incandescent 40W, LED 6W
• 800 lumens (60W equivalent): Incandescent 60W, LED 9W
• 1,100 lumens (75W equivalent): Incandescent 75W, LED 12W
• 1,600 lumens (100W equivalent): Incandescent 100W, LED 16W

Real-world example: A household with 30 bulbs averaging 4 hours of use per day at $0.13/kWh:

• Incandescent (60W each): $342/year in electricity
• LED (9W each): $51/year in electricity
• Annual savings: $291

Over the 25,000-hour life of one LED it burns about 225 kWh, roughly $29 of electricity at that rate. Twenty-five thousand hours of a 60W incandescent is 1,500 kWh, or about $195. The LED also saves you buying and fitting the twenty-five incandescent bulbs that would have burned out along the way.

Additional LED benefits: LEDs produce significantly less heat than incandescent bulbs, reducing air conditioning costs in warm climates. They are more durable, contain no mercury (unlike CFLs), turn on instantly at full brightness, and are available in a wide range of color temperatures from warm white (2700K) to cool daylight (5000K+).

Where to start

Not with the whole house. Start with the sockets that are actually on for hours: the kitchen, the porch light, the lamp beside the sofa. The saving scales directly with burn time, so one fitting used six hours a night is worth more than half a dozen closet lights you switch on twice a week. The rarely-used ones can wait until the old bulb dies on its own, which is also the cheapest moment to replace anything.