Lighting & Bulbs · 8 min read · Beginner

LED Bulbs Explained: Lumens, Watts, Colour Temperature & Dimming

Choose an LED lamp by brightness, colour and compatibility rather than relying on old incandescent wattage habits.

Key points & steps

Use lumens as the main brightness measure. LED wattage tells you electrical power consumption, not brightness by itself.
Use old-style watt equivalents only as a rough shopping aid because LED efficiency varies between products.
Choose colour temperature to suit the room: warm white is commonly around 2700K, neutral/cooler whites are often around 4000K, and higher Kelvin values appear progressively cooler/bluer.
Check whether the bulb is explicitly marked dimmable before using it with a dimmer. A dimmable lamp must also be compatible with the installed dimmer type and load range.
Check physical size as well as cap type. Large decorative globes or long filament lamps may not fit inside shades even when the base is correct.
For enclosed fittings, downlights or specialist lamps, check the fitting and lamp manufacturer’s compatibility and heat-management guidance.
If colour quality matters for kitchens, artwork or dressing areas, compare the lamp’s colour-rendering information as well as lumens and Kelvin value.

A lower-watt LED can be brighter than a higher-watt LED, so compare lumens rather than assuming wattage equals brightness.
Do not exceed the fitting manufacturer’s stated lamp rating even when changing to LED.
Smart bulbs can add app control, schedules and colour options, but they still need the correct physical cap and suitable fitting.