How to choose smart bulbs

Match the socket and the shape first

A smart bulb that does not fit the fixture is the most common return. Check the base printed on the old bulb, then the shape.

Measure the fixture too. A bulb with a bulky body can touch the shade, and a tall flood bulb can sit proud of a shallow recessed can. If a fixture is fully enclosed by a glass dome, look for a bulb whose package says it is suitable for enclosed fixtures. LEDs emit far less heat than incandescent bulbs, which release about 90% of their energy as heat according to the Department of Energy, but the electronics inside a smart bulb still last longer in open air.

Choose brightness in lumens, not watts

Watts measure power use, lumens measure light. The Department of Energy gives the usual conversion: about 450 lumens replaces a 40 W bulb, 800 lumens a 60 W bulb, 1,100 lumens a 75 W bulb and 1,600 lumens a 100 W bulb. Smart bulbs draw far less than the wattage they replace, so the package says something like “60 W equivalent, 9 W”.

• Bedside and reading lamps: 450–800 lumens is usually enough.
• Ceiling fixtures with several sockets: add the lumens of all bulbs. Three 800-lumen bulbs give about 2,400 lumens.
• Recessed cans: flood bulbs of 650–850 lumens are typical for a 5 or 6 inch can.
• Dimming range: a bulb you will mostly dim can be brighter than you need; a bulb you want to run at full output should not be undersized.

Pick the white tone: 2700 K to 5000 K

Color temperature is measured in kelvins (K). Lower numbers look warmer and yellower, higher numbers look whiter and bluer. ENERGY STAR lists nominal values of 2700, 3000, 3500, 4000, 5000 and 6500 K for its certified LED lamps.

• 2700 K: warm white, similar to an old incandescent bulb. Living rooms and bedrooms.
• 3000 K: soft white, slightly crisper. Kitchens and bathrooms where you still want warmth.
• 4000 K: neutral white for task areas, garages and home offices.
• 5000 K and above: daylight tones. Often too harsh for living spaces.

“Tunable white” bulbs move across a range, often 2700–6500 K, so one bulb can be warm in the evening and cool for work. “Color” bulbs add red, green and blue and cost more. Whatever you choose, keep bulbs in the same room at similar tones, because mixed whites look patchy.

How the bulb connects: Wi-Fi, Bluetooth, Zigbee or Thread

Zigbee is a self-healing mesh at 2.4 GHz and sub-GHz bands, and Thread is a low-power IP mesh built on the same IEEE 802.15.4 radio. In both, mains-powered bulbs relay signals for their neighbors, which is why a house with a dozen bulbs often gets more reliable, not less.

Where Matter helps, and where it does not

Matter lights can join Apple Home, Google Home, Alexa, SmartThings and Home Assistant, often at the same time, and respond locally. The Connectivity Standards Alliance lists lighting among Matter-certified product types. In practice, check two things: that the box says Matter and the radio (Thread or Wi-Fi), and that your controller app exposes the features you want, such as color or scenes. Some advanced features still live in the maker’s own app. Our guide on what Matter is explains the details.

Check these four things before you buy

1. Is the fixture on a dimmer? A smart bulb manages its own brightness. A dimmer chops the power it relies on and can cause flicker or dropouts. Replace the dimmer with a normal switch or a smart switch instead. See fixing LED flicker and buzz.
2. Does someone turn off the wall switch? A smart bulb with a dead switch cannot hear commands. Cover the switch with a guard or choose a smart switch instead. The trade-off is covered in smart bulbs vs smart switches.
3. Is the fixture enclosed? Check the “enclosed fixture” note on the package.
4. Will the bulb behave after an outage? Look at why smart bulbs turn on after a power outage and find the power-on setting in the app.

What it costs, and what you save

Plain white smart bulbs usually cost $8–$20 each and color bulbs $15–$50. ENERGY STAR certified bulbs use up to 90% less energy than standard bulbs and save about $55 in electricity over their lifetime, and the Department of Energy puts the saving of residential LEDs at 75% or more. A smart bulb’s radio draws a small amount of power all the time, so the saving comes from the LED, not from the “smart” part.