How many LED bulbs do I need to switch to save $100/year on electricity?

How many LED bulbs do I need to switch to save $100/year on electricity?

For most households, replacing 15–20 frequently-used incandescent or halogen bulbs with LEDs is enough to save $100 a year — sometimes more. The exact number depends on how many hours a day those lights run and what you pay per kilowatt-hour. The good news: even replacing just a handful of bulbs in high-use rooms gets you most of the way there.

The math is simpler than it looks, and in 2026 it's better than ever. Average residential electricity rates have climbed above 16 cents/kWh nationally, and LED prices have dropped below $2 per bulb. The payback period on a typical replacement is now under 6 months.

Use our free LED Bulb Energy & Cost Savings Calculator to run your own numbers — enter your bulb count, daily hours, and local rate to get a precise annual savings figure.

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The Math

A standard 60W incandescent bulb replaced by a 9W LED saves 51 watts per hour. Over a year, that gap adds up fast.

Here's the calculation for a single bulb running 5 hours a day:

Item	Calculation	Result
Watt savings per bulb	60W − 9W	51W
Hours of use per year	5 hrs/day × 365	1,825 hours
kWh saved per bulb	51W × 1,825 hrs ÷ 1,000	93 kWh
Dollar savings per bulb	93 kWh × $0.16/kWh	$14.88/year
Bulbs needed to hit $100	$100 ÷ $14.88	~7 bulbs

Seven bulbs — if each one runs 5 hours a day. That's a living room and a kitchen, roughly.

If your bulbs run less (say 2 hours/day), that savings-per-bulb drops to about $6, and you'd need closer to 17 bulbs to hit $100. The LED Bulb Energy & Cost Savings Calculator lets you adjust usage hours per bulb type, so you can model your actual mix — some lights run all evening, some barely switch on.

One thing worth knowing: the calculator uses the watt difference (old bulb minus new LED), not the LED wattage alone. That's the right way to measure savings, because you're only paying for the delta you eliminate.

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Variables That Change Your Answer

Your electricity rate

This single variable has the biggest impact. The national average is around $0.16/kWh, but Hawaii residents pay over $0.38/kWh, while Louisiana averages $0.11. At $0.38/kWh, a single 5-hour bulb saves $35 a year — meaning just 3 bulbs gets you to $100. At $0.11/kWh, you'd need 10. Check your utility bill for your actual rate; it changes the math dramatically.

How many hours the light actually runs

A bulb in a closet that flips on for 30 seconds a day saves almost nothing. A bulb in the kitchen running 8 hours a day saves nearly $24/year on its own. Focus your replacements on rooms where lights stay on — living areas, home offices, kitchens, exterior fixtures left on overnight.

The bulbs you're replacing

The savings come from the wattage gap between your old bulb and the LED replacement. Replacing a 100W bulb with an 13W LED saves 87W per hour — almost double the savings of swapping a 60W. Old halogen floodlights (often 65–90W) are particularly high-value targets. If you still have any BR30 or PAR38 halogens in recessed cans, those should be first on your list.

Bulb lifespan and replacement cost

LEDs rated for 15,000–25,000 hours last 10–25 years at 5 hrs/day. The current cost of a quality LED is $1.50–$4.00 per bulb. Even at $4, you recoup the cost in under 4 months for a 5-hour-a-day bulb at national average rates. The LED Bulb Energy & Cost Savings Calculator includes a payback period field so you can see this directly.

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FAQ

Do smart bulbs save more energy than regular LEDs?

No — smart bulbs and standard LEDs use roughly the same wattage when on. Smart bulbs can help if they're preventing lights from staying on when nobody's home, but the energy draw while lit is nearly identical to a dumb LED.

Will switching to LEDs noticeably dim my house?

Not if you match lumens, not watts. A 60W incandescent produces about 800 lumens. An LED labeled "60W equivalent" produces the same brightness at 8–10W. Look for the lumen number on the package, not the watt number.

How much does it cost to switch every bulb in a typical house?

The average U.S. home has 30–40 light sockets. At $2–3 per LED, a full switchover runs $60–$120 in bulbs. At $14–20 in annual savings per high-use bulb, that pays back in 6–12 months — and then keeps saving for a decade.

Is there a rebate for switching to LED bulbs?

Many utilities still offer LED rebate programs, typically $1–3 per bulb at the point of sale. Check your utility's website or the DSIRE database (dsireusa.org) for current programs in your state. Some home improvement stores also apply these discounts automatically at checkout.

Does it make sense to replace bulbs before they burn out?

For bulbs you use more than 3–4 hours a day, yes — the energy savings exceed the cost of the new LED within a few months, so waiting for the old bulb to fail just delays savings. For bulbs you rarely use, it's fine to wait.

Ready to see your exact number? Use the LED Bulb Energy & Cost Savings Calculator — enter your bulbs, hours, and rate to find out how many swaps you need to hit $100 in annual savings.