LED Bulb Savings Calculator
Calculate savings from switching to LED bulbs
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LED Bulb Savings Calculator helps you calculate savings from switching to LED bulbs without a spreadsheet. Drop Current Bulb Wattage, LED Wattage and Number of Bulbs into LED Bulb Savings — the figure refreshes as you type. Nothing in LED Bulb Savings is a black box. LED Bulb Savings replaces guesswork. You can disconnect once LED Bulb Savings has loaded; the arithmetic runs locally. LED Bulb Savings sits in the Home & Garden section next to led vs incandescent and energy saving bulbs. The labels in LED Bulb Savings match the terms in its result. LED Bulb Savings answers the next Home & Garden question you meet.
LED light bulb savings and running cost
Enter the wattage of the bulbs in place and of the LEDs replacing them, plus the hours they run and the price of electricity, and the page returns the annual running cost and the saving. The defaults save $111.69 a year across the bulbs entered.
The ten LEDs cost $50, so they pay for themselves in about 5.4 months.
The formula
Saving = bulbs × (old watts − new watts) × hours per day × 365 ÷ 1000 × rate
10 × 51 × 5 × 365 ÷ 1000 = 930.75 kWh; × $0.12 = $111.69.
Worked examples
10 bulbs, 60 W → 9 W, 5 h/day, $0.12 → $111.69/yr
10 bulbs, 60 W → 9 W, 2 h/day → $44.68/yr
20 bulbs, 60 W → 9 W, 5 h/day → $223.38/yr
10 bulbs, 100 W → 12 W, 5 h/day → $192.75/yr
Why the payback is so short
An incandescent turns about 5% of its electricity into light and the rest into heat, so almost the entire saving is real energy rather than a difference in brightness. LED costs have fallen to the point where the bulb price is recovered in months on any light used daily. Lights used ten minutes a day in a cupboard are a different calculation — there the bulb may age out before it pays back.
What the figure ignores
- Heating season. In a heated room the old bulb's waste heat was partly useful, so the winter saving is slightly smaller than calculated.
- Cooling season. The reverse applies in summer: less waste heat means less air conditioning.
- Bulb life. An LED rated for 15,000 hours replaces roughly 15 incandescents at 1,000 hours each, which adds to the saving.
- Dimming and controls. Some LEDs need compatible dimmers, and a poorly matched dimmer shortens life.
Prioritise the lights that run longest — kitchen, living room, hallway — before the ones used for minutes at a time.
The payback is the number to check before buying: at five hours a day, ten bulbs save $111.69 a year and repay their $50 cost in about five months. That assumes the LED lasts as long as claimed — most are rated for 15,000 hours or more, which at this usage is over eight years. Cold locations, dimmers and enclosed fittings shorten real life, so a cheap bulb in a hot recessed fixture may never reach the payback.
Frequently Asked Questions
How much do LED bulbs save?
Ten 60 W bulbs replaced with 9 W LEDs save about $112 a year at five hours a day and 12 cents a kWh.
How long until the bulbs pay for themselves?
About five and a half months on these defaults — $50 of bulbs against $112 a year of savings.
Does the saving depend on hours used?
Almost entirely. Halving the daily hours halves the saving, so replace the most-used lights first.
Do LEDs really use that much less?
Yes. An incandescent converts about 95% of its energy to heat, so an LED producing the same light uses roughly a sixth of the electricity.
Does the waste heat from old bulbs help in winter?
Slightly. In a heated room the heat was not entirely wasted, so the real annual saving is a little lower than the calculation suggests.
Are LED bulbs worth it in rarely used rooms?
Less so. A cupboard light used a few minutes a day may not recover the bulb price before it fails.
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