Choosing a bulb used to mean choosing a wattage. Today, with LEDs dominating, the useful numbers are different: lumens for brightness, kelvin for color, and CRI for how accurately colors look.
LED
LEDs are now the standard choice for home lighting. They use much less energy than incandescent bulbs for the same light and last many years; the Department of Energy notes they also last far longer than incandescents. They are available in almost every shape, color temperature and base, and many are dimmable.
Things to check: cheap LEDs can flicker or hum, especially on old dimmers. Look for “dimmable” if needed, and a good CRI (90 or more) where colors matter.
Incandescent
The traditional bulb with a glowing filament: warm, flattering light and a perfect color rendering, but very inefficient because most of the energy becomes heat. US efficiency standards that took full effect in 2023 have removed most general-purpose incandescent bulbs from stores. Some specialty bulbs (appliance, some decorative types) remain.
Halogen
A type of incandescent bulb with halogen gas, a bit more efficient and very bright and crisp. Still inefficient compared to LEDs, and it runs very hot. Mostly found in older track lights and some specialty uses.
CFL (compact fluorescent)
The spiral bulbs that were popular in the 2000s. More efficient than incandescent but they take time to warm up, often do not dim well, and contain a small amount of mercury, so they must be recycled rather than thrown away. Like incandescent bulbs, they have largely disappeared from shelves in favor of LEDs.
Smart bulbs
LED bulbs that you control from an app, a voice assistant or a hub. They can change brightness and often color, follow schedules and simulate presence when you are away. Some need a hub; others connect directly to Wi-Fi or Bluetooth.
How to read the box
- **Lumens**: brightness. About 800 lumens equals an old 60 W bulb; 1,100 lumens is about 75 W; 1,600 lumens about 100 W.
- **Color temperature (K)**: 2700 K is warm white, 3000 K soft white, 4000 K neutral, 5000 K and above daylight. See planning layered lighting for where to use each.
- **CRI**: color rendering index, out of 100. Above 90 is excellent for kitchens, bathrooms and art.
- **Base**: E26 is the standard US screw base, E12 the small candelabra base, GU10 and GU5.3 are pin bases used in spotlights.
- **Damp or wet rated**: for bathrooms and outdoor fixtures.
Bottom line
For almost every fixture in the house, a quality LED with the right lumens, warm or neutral color and a high CRI is the best choice. Switching remaining old bulbs is one of the quick steps in saving energy at home.
