How much does it cost to run an incandescent bulb?

An incandescent bulb is cheap to run one at a time — 60 watts for five hours a day is only a few dollars a year — which is exactly why nobody bothered replacing them for decades. The math only turns ugly when you count how many are burning in a typical house: a hallway, two lamps, a porch light and a ceiling fixture can add up to 300+ watts of pure heat-and-light, and unlike a space heater you rarely think to turn them all off.

The real cost isn't the bulb, it's the alternative you're not using. An LED making the same light draws about 9 watts instead of 60 — roughly 85% less — so every incandescent socket in the house is a small, silent recurring charge that a $2 bulb swap erases almost instantly. Left in place, it's one of the few electricity costs that's still fully within your control with zero change in behavior required.

What drives the cost of running an incandescent bulb

• Wattage is the whole story: a 60W bulb draws roughly 6-7x more power than an LED equivalent for the same brightness, so the bulb type matters more than how long it's on
• Hours per day compounds fast — a porch light or hallway fixture left on 5+ hours a day adds up over a billing cycle even at 60W
• It's rarely one bulb: most of the cost comes from running several incandescent fixtures in the same house at once, not any single socket

How to cut it

• Swap it for an LED equivalent — same light output at about 9W instead of 60W, roughly an 85% cut with no change in habits
• Reserve remaining incandescents for low-use spots (closets, storage) where the swap cost isn't worth it yet
• Use a dimmer or occupancy sensor in rooms where the bulb gets left on out of habit, not need
• Prioritize the bulbs that run longest each day (porch, kitchen, living room) — swapping those first returns the most savings per dollar spent