LED vs Incandescent Bulbs: How Much Do You Really Save?

Is a five-dollar LED bulb really a better deal than a one-dollar bulb from the old box? The answer comes down to simple multiplication, and the result is bigger than many people expect.

What Changes When You Swap the Bulb

An LED turns more of its power into light, so it needs far less power for similar brightness. Engineers call this light produced per watt luminous efficacy. ENERGY STAR says LED products make light up to 90% more efficiently than incandescent bulbs. That is a maximum, not a promise for every bulb.

The old bulb wastes most of its power as heat. ENERGY STAR notes that incandescent bulbs release about 90% of their energy as heat. The table uses a 60 W bulb and an 8 W LED of similar brightness as a working example.

Brightness is the part to check on a real bulb. Read the Lighting Facts label on the box instead of trusting a wattage guess. You can plug your own bulbs into our LED savings calculator once you have those numbers.

The Running Cost Formula in Four Steps

You only need one formula to price any bulb. Multiply watts by hours per day, then by 365, then divide by 1,000. The result is kilowatt-hours per year, and your rate turns it into dollars.

Dividing by 1,000 turns watt-hours into kilowatt-hours. If that unit is new to you, our guide to kWh and electricity units explains it. Your rate is printed on your bill. Our page on how to read your electricity bill shows where to find it.

Curious how watts connect to current and voltage? Ohm’s law explained covers that electrical side in plain language.

Here is a quick check on the unit step. A 100-watt load running for 10 hours uses 1,000 watt-hours, which is exactly 1 kWh. To get a daily cost instead of a yearly one, simply skip the 365 step.

Worked Example: 60 W vs 8 W at 3 Hours a Day

Let us price both bulbs for one year. The example assumes 3 hours of use a day and a rate of $0.16 per kWh. That rate is only an example, so swap in the rate from your own bill.

1. Incandescent: 60 × 3 × 365 ÷ 1,000 = 65.7 kWh. At $0.16, that costs $10.51 a year.
2. LED: 8 × 3 × 365 ÷ 1,000 = 8.76 kWh. At $0.16, that costs $1.40 a year.
3. Savings: 65.7 minus 8.76 is 56.94 kWh. That is $9.11 saved per bulb each year.

The LED draws about 13% of the power, since 8 divided by 60 is 0.133. Every number here assumes both bulbs give the same light. If you pick a dimmer bulb, the comparison is no longer fair.

Now scale it up. A home with five bulbs that run the same hours would save about $45.55 a year.

How Fast an LED Pays Back

Payback is the extra purchase price divided by the yearly savings. With example prices of $1 and $5, the premium is $4. Divide $4 by $9.11 and you get about 0.44 years, or roughly five months.

After that point, every month of use is savings. Five bulbs cost $20 more up front, and $45.55 a year in savings gives the same five-month payback. A bulb in a rarely used closet will take far longer, because it runs fewer hours.

This is a simple payback figure. Sale prices on LEDs shorten it, and a pricier specialty bulb stretches it. Try the math with the prices on your own shelf before you buy a whole case.

This is why the busiest lights come first. Kitchen, living room and porch bulbs rack up hours quickly. To price other appliances the same way, try our electricity cost calculator.

Why Your Rate and Hours Change the Answer

Savings grow in a straight line with both your rate and your daily hours. Cheap power or short use shrinks the gain, while costly power or long use grows it. The table shows one bulb under different conditions.

Notice that the $0.16 rate is only an example, not a national average. Rates vary by place and change over time, so recheck your bill once a year.

Find your own price on your bill. The U.S. Energy Information Administration also publishes average electricity prices if you want a national benchmark.

Bulb Life and Heat Beyond the Power Bill

Life matters as much as power. At 3 hours a day, a 25,000-hour LED lasts about 22.8 years. A 1,000-hour incandescent lasts about 0.9 years. Over one LED life, you would buy about 24 replacement incandescent bulbs.

Heavier use shortens the calendar life. At 5 hours a day, the same 25,000 hours lasts about 13.7 years. Rated hours are also examples, so check the package for the claim a maker actually makes.

Rated life has a specific meaning. ENERGY STAR defines an LED’s life as the point where light output falls to 70% of the original. LEDs dim gradually instead of burning out all at once.

Heat is the hidden cost. In cooling season, the wasted heat from an old bulb can add load to your air conditioner. An LED wastes far less, so the saving can reach beyond the lighting line on your bill.

FAQs About LED vs Incandescent Savings

Sources and Further Reading

This article is general education, not electrical, financial or engineering advice. Prices, rates and products vary by place, so confirm your own electricity rate and the label on the bulb before you buy. Reviewed for accuracy by Prof. Dr. Khalil Mudassar, PhD. Last updated 2026-10-13.