Light Bulb Wattage Guide: Incandescent vs CFL vs LED Equivalents
For decades, we bought light bulbs based on watts. Today, watts tell you how much energy a bulb uses, not how bright it is. Learn how to convert the old incandescent standards to modern LED equivalents.
The Shift from Watts to Lumens
Historically, an incandescent light bulb worked by passing electricity through a tungsten filament until it got so hot it glowed. This process was incredibly inefficient—90% of the energy was wasted as heat, and only 10% became visible light.
In that era, Watts = Brightness. Everyone knew that a 60W bulb was for the living room and a 100W bulb was for the garage.
Today, with the advent of Light Emitting Diodes (LEDs), the rules have changed. LEDs do not use heat to create light; they use semiconductors. This means they can produce the exact same amount of light using 80% to 90% fewer watts. Therefore, to measure brightness, we now use Lumens.
Look at Lumens for brightness.
Look at Watts for energy consumption.
LED Equivalent Conversion Chart
If you have an old fixture that says "Max 60 Watts" and you want to replace the bulb, here is how the brightness (Lumens) scales across older technologies versus modern LEDs.
| Brightness (Lumens) | Old Incandescent | CFL (Spiral) | Modern LED |
|---|---|---|---|
| ~400 - 450 Lumens | 40 Watts | 9 - 11 Watts | 5 - 6 Watts |
| ~800 - 850 Lumens | 60 Watts | 13 - 15 Watts | 8 - 10 Watts |
| ~1,100 Lumens | 75 Watts | 18 - 20 Watts | 11 - 13 Watts |
| ~1,600 Lumens | 100 Watts | 23 - 26 Watts | 14 - 17 Watts |
| ~2,600 Lumens | 150 Watts | 38 - 42 Watts | 22 - 26 Watts |
The "Max Wattage" Warning on Fixtures
Every lamp socket has a safety warning sticker: "Caution: Maximum 60W Bulb."
This warning exists to prevent heat damage and fire. A 100W incandescent bulb gets dangerously hot and can melt the plastic socket or scorch the lampshade of a fixture rated for 60W.
The LED Hack: Because a 100W-equivalent LED bulb only physically draws 15 Watts and emits almost no heat, it is 100% safe to put a 15W LED (1,600 lumens) into a socket rated for a maximum of 60 Watts. The fixture only cares about the actual electrical power (15W), not the equivalent brightness label!
Calculating Savings with LEDs
Switching your home to LEDs results in massive energy savings. Let's compare leaving one old 60W bulb on for 6 hours a day vs a 9W LED, at $0.15/kWh.
New 9W LED: 9W × 6h × 365 days = 19.7 kWh = $2.95 / year
By replacing just ten 60W bulbs with LEDs, you save over $165 per year on your electricity bill.