How to work out LED savings
A bulb's cost to run is its watts times the hours it's on times your rate. The savings from an LED are just the watts you stop using. Here is the math with the values the calculator opens with: ten 60-watt incandescent bulbs replaced by 9-watt LEDs, on 3 hours a day, at the U.S. average rate and $2 per LED.
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1
Find the watts you save
60 W − 9 W = 51 W per bulb. Ten bulbs save 510 W while they're on.
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Turn it into kWh per year
510 W × 3 hours × 365 days ÷ 1,000 = 558.5 kWh a year.
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3
Multiply by your rate
558.5 kWh × $0.1816 (the U.S. average in August 2026, per the EIA) = $101.41 a year. The old bulbs cost $119.31 a year to run; the LEDs cost $17.90.
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Divide the bulb cost by the monthly savings
Ten LEDs at $2 cost $20. $101.41 a year is $8.45 a month, so they pay for themselves in 2.4 months.
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5
Count the whole life of the bulb
At 3 hours a day, a 15,000-hour LED lasts 13.7 years. Over that time each bulb saves 765 kWh. For ten bulbs that's 7,650 kWh, or $1,389 at today's rate, $1,369 after the cost of the LEDs.
The default 3 hours a day is the figure the FTC uses for the yearly cost on every bulb box's Lighting Facts label. Kitchen and living room lights often run 5 hours or more, closets and guest rooms far less. Use one row per room type for a better estimate.
Which LED replaces which bulb
Shop by lumens, not watts. Lumens measure light. Watts only told you brightness back when every bulb was an incandescent. Savings per bulb assume 3 hours a day at 18.16¢ per kWh.
| Old bulb | Lumens | LED | Saves/yr |
|---|---|---|---|
| 40 W incandescent | 450 | 6 W | $6.76 |
| 60 W incandescent | 800 | 9 W | $10.14 |
| 75 W incandescent | 1,100 | 11 W | $12.73 |
| 100 W incandescent | 1,600 | 15 W | $16.90 |
| 43 W halogen | 750 | 9 W | $6.76 |
| 72 W halogen | 1,490 | 15 W | $11.33 |
| 65 W flood (BR30) | 650 | 9 W | $11.14 |
| 90 W halogen flood (PAR38) | 1,300 | 13 W | $15.31 |
| 13 W CFL | 800 | 9 W | $0.80 |
| 23 W CFL | 1,600 | 15 W | $1.59 |
Lumens for halogen and flood bulbs are typical values; check your old box if you still have it. While you're reading the LED box, look at color temperature too: 2700K is the warm white of an old incandescent, 3000K is a bit crisper, and 4000K to 5000K looks cool and bluish.
Hours matter more than anything
An LED only saves while the light is on. The same 60-to-9-watt swap pays back in weeks in a kitchen and in years in a closet. Per bulb, at the U.S. average rate and $2 per LED:
| Hours a day | Saves/yr | Payback | 15,000 h lasts |
|---|---|---|---|
| 1 (closet, guest room) | $3.38 | 7.1 months | 41 years |
| 3 (typical) | $10.14 | 2.4 months | 13.7 years |
| 5 (kitchen, living room) | $16.90 | 1.4 months | 8.2 years |
| 8 (porch light, evenings) | $27.04 | 0.9 months | 5.1 years |
| 12 (dusk to dawn) | $40.57 | 0.6 months | 3.4 years |
That's why to start with the lights you use most: kitchen, living room, outdoor fixtures on a timer and any old halogen floods. Those pay back almost at once.
How long each type of bulb lasts
The DOE says ENERGY STAR LEDs use at least 75% less energy than incandescent bulbs and last up to 25 times longer. Typical rated lives:
| Bulb | Rated life | At 3 h a day |
|---|---|---|
| Incandescent | about 1,000 h | under 1 year |
| Halogen | 1,000–3,000 h | 1–3 years |
| CFL | 8,000–10,000 h | 7–9 years |
| LED (ENERGY STAR) | 15,000–25,000 h | 13.7–22.8 years |
An LED's rated life is when it drops to 70% of its original brightness, not when it dies. Heat is the enemy: an LED in a sealed globe or recessed can runs hotter and fades sooner. Buy bulbs marked for enclosed fixtures for those spots, and dimmable bulbs for dimmer switches. If a new LED flickers or buzzes on an old dimmer, the dimmer may need an LED-rated replacement, a quick job for an electrician.
What it costs to switch
Standard A19 LEDs (the classic bulb shape) are cheap now: value packs of 60-watt-equivalent bulbs sell for roughly $1 to $1.50 a bulb, and name brands for about $2 to $4. Floods, candelabra bulbs, smart bulbs and high-CRI bulbs cost more, from $4 to $15 or so. The calculator uses one price for all bulbs; enter an average if you're buying a mix.
Changing a bulb is a DIY job. You don't need a pro unless you are replacing whole fixtures, adding recessed lighting or swapping dimmer switches, which means working inside the electrical box. Turn off the breaker for that kind of work, or hire a licensed electrician.
There's a small catch for homes with electric heat. Old bulbs give off most of their energy as heat, so in winter a little of what you save on lighting comes back as heating. In summer the opposite happens: cooler bulbs mean less work for the AC. For most homes the net effect is small.
Common questions
How much money do LED bulbs save?
Swapping one 60-watt incandescent for a 9-watt LED saves 51 watts. At 3 hours a day that is about 56 kWh a year, or $10.14 at the August 2026 U.S. average of 18.16 cents per kWh. Ten bulbs save about $101 a year.
How long does it take for LED bulbs to pay for themselves?
Replacing a 60-watt incandescent used 3 hours a day, a $2 LED pays for itself in about 2.4 months at the U.S. average rate. Brighter bulbs and longer hours pay back faster. Replacing a working CFL takes about 2.5 years, so most people wait until the CFL burns out.
What LED wattage replaces a 60-watt bulb?
Look for about 800 lumens, which is what a 60-watt incandescent put out. LEDs reach that with 8 to 10 watts. For a 75-watt bulb look for 1,100 lumens (about 11 watts) and for a 100-watt bulb 1,600 lumens (about 15 watts).
How long do LED bulbs last?
ENERGY STAR certified LED bulbs are rated for at least 15,000 hours, about 13.7 years at 3 hours a day, and many are rated 25,000 hours. An incandescent bulb lasted about 1,000 hours. Heat shortens LED life, so enclosed fixtures should use bulbs rated for them.
Is it worth replacing CFL bulbs with LEDs?
Not right away for most CFLs. A 13-watt CFL to a 9-watt LED saves only 4 watts, about 80 cents a year at 3 hours a day. Replace CFLs as they burn out, and recycle them, since they contain a small amount of mercury.
Can you still buy incandescent light bulbs?
Mostly no. Since August 2023, federal efficiency rules require general-purpose bulbs to make at least 45 lumens per watt, which standard incandescent and most halogen bulbs cannot. Some specialty bulbs, such as appliance bulbs, are exempt.
Sources and assumptions
- Electricity rates: U.S. Energy Information Administration, Electric Power Monthly, Table 5.6.A, average residential price for August 2026 (preliminary), the same rates as our electric bill calculator.
- Energy use and life: DOE Energy Saver, LED Lighting (at least 75% less energy, up to 25 times longer than incandescent). ENERGY STAR LED bulbs are rated for at least 15,000 hours, per Efficiency Vermont's LED guide; rated life is the L70 point, when output falls to 70%.
- Lumens per old bulb: ENERGY STAR, Learn About Brightness (450, 800, 1,100 and 1,600 lumens for 40, 60, 75 and 100 W). LED wattages are typical of 2026 retail bulbs; check the box.
- Hours: 3 hours a day matches the basis of the FTC Lighting Facts label on bulb packaging.
- Incandescent rules: DOE, General Service Lamps standards (45 lumens per watt minimum, enforced from August 2023).
- LED price: $2 per bulb is an estimate for 60-watt-equivalent A19 bulbs, from online retail listings checked in October 2026 (value packs about $0.85 to $1.40 a bulb, name brands more). Edit it for your bulbs.
- Not counted: the cost of replacement bulbs you no longer buy, heating and cooling interactions, and fixed fees on your bill. Lifetime savings use today's rate with no inflation.