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LED Lighting Savings Calculator: Switch from Incandescent & Save

LEDs use roughly 85% less energy than incandescent bulbs for the same light, so switching a whole home's bulbs adds up fast. A single 60-watt incandescent replaced by a 9-watt LED saves about 51 kWh per year if it runs 4 hours a day. Multiply that across 20 or 30 bulbs and the annual savings become meaningful — often $60–$120 or more at average US electricity rates. This calculator shows the exact numbers for your home: old annual cost, LED annual cost, dollar savings, energy saved, and the percentage reduction in lighting electricity use.

Number of bulbs
Old bulb wattage(W)

Typical incandescent: 40W, 60W, 75W, or 100W.

LED replacement wattage(W)

A 9W LED replaces a 60W incandescent; 12W replaces 75W; 15W replaces 100W.

Hours used per day per bulb 4hrs/day
State (auto-fills rate)
Electricity rate($/kWh)
Old annual cost
$297.84

1,752 kWh/yr at $0.170/kWh

LED annual cost
$44.68

263 kWh/yr at $0.170/kWh

Annual savings
$253.16

old cost − LED cost

Energy saved
1,489kWh/yr

1,752 − 263 kWh

Energy reduction
85.0%

less electricity than incandescent

Results update live as you type. For planning and field-check estimates — always verify against applicable standards and equipment ratings.

How LED lighting savings are calculated

The calculation compares annual electricity cost before and after switching to LEDs. For each scenario, annual energy equals the number of bulbs multiplied by the bulb wattage (converted to kilowatts) multiplied by daily hours and 365 days. Cost is simply energy times the electricity rate.

The savings come entirely from the wattage gap. A 60-watt incandescent running 4 hours per day uses 87.6 kWh per year. Its 9-watt LED equivalent uses just 13.1 kWh — a 74.5 kWh reduction per bulb. At $0.17/kWh, that's about $12.67 saved per bulb per year. Across 20 bulbs, the household saves roughly $253 annually from lighting alone.

Two factors drive the magnitude of savings: how many hours per day the lights run, and how large the wattage gap is. Lights that run 8–10 hours a day (always-on outdoor lights, kitchen fixtures, living rooms) save proportionally more than bedroom lights used for an hour each evening. Replacing 100-watt incandescents with 15-watt LEDs saves even more per bulb than the 60W→9W swap this calculator defaults to.

Frequently asked questions

Switching 20 bulbs from 60-watt incandescent to 9-watt LED, running 4 hours per day at the US average of $0.17/kWh, saves about $253 per year. Results scale directly with usage: if those same lights run 8 hours per day, annual savings double to roughly $506. A single bulb running 4 hours daily saves about $12.67 per year — small in isolation, but meaningful across a whole home. Households in high-rate states like California or Hawaii ($0.25–$0.35/kWh) save proportionally more.

Yes — almost universally. A quality LED bulb costs $2–$5 at retail today, compared to $1 or less for a cheap incandescent. At $12–$15 in annual savings per bulb (at average usage and rates), the payback is typically 3–6 months. LEDs also last 15,000–25,000 hours compared to 1,000–2,000 hours for incandescents, so you avoid 10–15 bulb replacements over the LED's lifetime. The total cost of ownership — purchase price plus electricity — strongly favors LEDs in virtually every scenario.

Modern LEDs produce the same light output (lumens) as an incandescent using about 85% less electricity. A 9-watt LED replaces a 60-watt incandescent; a 12-watt LED replaces a 75-watt; a 15-watt LED replaces a 100-watt. The efficiency gap exists because incandescent bulbs convert only about 5–10% of their energy into visible light — the rest becomes heat. LEDs use solid-state electronics to convert electricity directly into light, wasting far less as heat. That 85% efficiency advantage is why lighting accounts for a shrinking share of home electricity bills even as homes get larger and brighter.

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