LED vs incandescent bulbs: which costs less over time
LED vs incandescent bulbs: an LED costs more at the shelf but less over its life. Here is the simple math, with round example numbers you can swap for yours.
Hamza Idrissi4 min read
Verdict: LED wins on cost over time, almost every time. An old-style incandescent bulb is cheap on the shelf and costly to run. An LED is the reverse. In an LED vs incandescent cost check, the bulbs you leave on longest are where the LED pays off first.
Why: an incandescent bulb turns most of its power into heat, not light. An LED makes light with much less power. The maker's box shows the watts used and the hours of life. Those two numbers are all you need.
Which wins on
| Factor | LED | Incandescent |
|---|---|---|
| Price at the shelf | Higher | Lower |
| Power used for the same light | Much lower, often a fraction | Much higher |
| Life, from the box | Often many thousands of hours | Often about a thousand hours |
| Heat | Cool to the touch, mostly | Hot |
| Replacing | Rarely | Often |
| Best use | Lamps and lights on for hours | Almost none now |
Incandescent bulbs are also being phased out of sale in many places, so check what your shop carries. Rules differ by country.
The math with round numbers
These are example numbers, not real prices. Swap in the ones from your own box and your power bill.
Say a light is on 4 hours a day. That is about 1,460 hours a year.
- Incandescent: uses 60 watts. Example price $1. Lasts around 1,000 hours, so you buy about 1.5 a year.
- LED: gives the same light at 9 watts. Example price $3. Lasts 15,000 hours, so one bulb lasts about 10 years at this use.
Power use per year: 60 watts x 1,460 hours = 87.6 kilowatt-hours. For the LED: 9 x 1,460 = 13.1 kilowatt-hours.
Say power costs $0.15 per kilowatt-hour. That is an example rate. Look at your bill for yours.
- Incandescent power per year: 87.6 x $0.15 = about $13.
- LED power per year: 13.1 x $0.15 = about $2.
So one lamp saves roughly $11 a year in power, plus the cost of buying bulbs again. The LED pays back its extra $2 within the first few months. After that, it is nearly all savings.
Pick LED if
- The light is on more than an hour or two a day.
- You hate climbing a ladder to change bulbs.
- The fitting is hot or hard to reach, such as a hallway ceiling.
- You want to cut your bill without changing how you live.
Pick incandescent only if
- You already own a stock and the light is on a few minutes a day, like a cupboard or an attic.
- The fitting is old and the LED does not fit or flickers. Try a different LED type first.
What to check on an LED box
- Lumens for brightness. A bulb around 800 lumens is close to the old 60 watt bulb.
- Color temperature, in K. Around 2700K is warm and yellow. 5000K is cool and bluish.
- Dimmable. If the lamp is on a dimmer, the box must say the bulb is dimmable.
- Base size. Match the base to the old bulb.
- Safety mark on the box, such as the one used in your country.
The rule that matters most: buy LEDs for the lamps used most, and match the lumens, not the watts.
Common mistakes
- Buying by watts. LED watts are low, so look at lumens.
- Putting a non-dimmable LED on a dimmer. It may flicker or buzz.
- Swapping every bulb in one go. Start with the five most-used lamps and do the rest as old ones burn out.
- Choosing "daylight" for a bedroom, then hating the light.
For more small buys that are worth the money, see things worth buying under $25. The method behind the math above is in cost per use, explained.
Quick questions
Do LED bulbs really last that long?
The box gives a rated life, and real life can be shorter in hot or enclosed fixtures. Even at half the rated life, an LED usually outlasts several old bulbs.
Are LEDs worth it for a light I rarely use?
Less so. The power saved is small if the light is on a few minutes a day. Swap when the old bulb burns out.
Why does my LED flicker?
Common causes are a dimmer that does not match, a loose fitting or a cheap bulb. Try a bulb marked dimmable, or ask an electrician if it keeps happening.
Can I use an LED in an enclosed fixture?
Check the box. Some bulbs are not rated for closed fixtures because heat shortens their life.
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