LED Savings Calculator

Please fill in the required fields with values greater than 0.
–energy saved per year (kWh)
–money saved per year
–money saved over 10 years
–payback time

Estimate only. LED bulbs also last much longer, so you save on replacements. Prices vary.

How to use this calculator

Enter how many bulbs you want to replace, the watts of the old and LED bulbs, how long they are on each day and your electricity rate. Press Calculate to see the yearly saving and the payback time.

The formula

Energy saved (kWh) = (old watts − LED watts) × bulbs × hours × 365 ÷ 1,000
Money saved = kWh saved × rate
Payback = cost of new bulbs ÷ monthly saving

Example: Replacing 10 incandescent 60 W bulbs with 9 W LEDs used 3 hours a day at $0.17 per kWh saves about 558 kWh and $94.94 a year. The bulbs pay for themselves in under 4 months.

Understanding your LED savings

This calculator shows how much energy and money you save by replacing older bulbs with LEDs, and how quickly the new bulbs pay for themselves. The savings come from the drop in watts. LEDs make the same amount of light with far less power.

What the result means in practice

The yearly saving repeats every year the bulbs stay in use. The payback time tells you when the purchase price is covered. After that, the savings are yours. Because LEDs also last much longer, you buy fewer replacement bulbs, which is an extra saving the calculator does not include.

A real-world example

Say you replace 5 old 100 W bulbs with 14 W LEDs that give similar light. If they run 5 hours a day at $0.15 per kWh, you save 86 W per bulb. That is about 785 kWh per year, or about $118. If each LED costs $4, the $20 total pays for itself in about 2 months.

Main factors that change your savings

  • Hours of use: Bulbs that are on many hours a day save the most. Swap the busiest fixtures first.
  • Old bulb type: Replacing incandescent or halogen bulbs saves much more than replacing CFLs, which are already fairly efficient.
  • Electricity rate: Higher rates mean faster payback.
  • Bulb price: Multipacks lower the cost per bulb and shorten payback.

Tips and common mistakes

  • Shop by lumens, not watts. Lumens measure brightness. About 800 lumens matches an old 60 W bulb.
  • Pick the right color temperature. About 2700K gives a warm look, while 4000K to 5000K looks cooler and whiter.
  • Check the fixture. Enclosed fixtures can shorten LED life unless the bulb is rated for them.
  • Use dimmable LEDs only with compatible dimmers to avoid flicker or buzzing.
  • Do not overestimate hours. A closet light used a few minutes a day saves very little.

Planning your switch

Start with the rooms you use most, such as the kitchen, living room and outdoor lights left on all evening. Run the calculator for each group of bulbs with its own hours. Check whether your utility offers discounts or rebates on LED bulbs, which can shorten payback even more. Recycle old CFLs properly, since they contain a small amount of mercury.

Frequently asked questions

How much money do LED bulbs save?
An LED uses about 80 to 90 percent less energy than an incandescent bulb with the same brightness.
What LED wattage replaces a 60 watt bulb?
A 9 to 10 watt LED gives about the same light as a 60 watt incandescent bulb, about 800 lumens.
How long do LED bulbs last?
Most last 15,000 to 25,000 hours, about 10 to 20 years of normal use.
Are LED bulbs worth the cost?
Yes. They usually repay their price in under a year and then keep saving money.
Do LED bulbs work with dimmers?
Only if the bulb is marked as dimmable and the dimmer is compatible.
Do LED bulbs get hot?
LEDs run much cooler than incandescent bulbs because they turn more of their power into light instead of heat. The base of an LED can still get warm, since it contains electronics that need to shed heat. That is why some LEDs are not rated for fully enclosed fixtures. Check the package for enclosed-fixture ratings.
What color temperature LED should I choose?
Color temperature is measured in kelvin (K). Around 2700K to 3000K gives warm, yellowish light similar to old incandescent bulbs, which suits living rooms and bedrooms. Around 3500K to 4000K is neutral white, common in kitchens and bathrooms. 5000K and above looks bluish and bright, often used in garages and workspaces.
Is it worth replacing CFL bulbs with LEDs?
The savings are smaller because CFLs are already fairly efficient. A 13 W CFL replaced by a 9 W LED saves only 4 W per bulb. Many people replace CFLs as they burn out rather than all at once. LEDs do offer instant full brightness, better dimming and no mercury, which are reasons beyond energy cost.