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Yes — a smart bulb switched off still draws about 0.2 to 0.5 watts, because its radio must stay awake to receive the command to turn back on. At the US average residential rate of roughly 17 cents per kilowatt-hour reported by the Energy Information Administration, 0.3 watts of continuous standby works out to about 2.6 kilowatt-hours and 45 cents per bulb per year. Ten bulbs cost four to five dollars annually; twenty cost about nine. Cutting power at the wall switch eliminates the draw entirely but also disables app control, schedules and voice commands.
What does standby actually cost?
| Smart bulbs | Standby at 0.3 W each | kWh per year | Cost per year at 17¢/kWh |
|---|---|---|---|
| 1 | 0.3 W | 2.6 | $0.45 |
| 5 | 1.5 W | 13.1 | $2.23 |
| 10 | 3.0 W | 26.3 | $4.47 |
| 20 | 6.0 W | 52.6 | $8.94 |
| 40 (whole house) | 12.0 W | 105.1 | $17.87 |
Rates vary widely by state, from roughly 11 cents in parts of the Midwest and South to well over 30 cents in Hawaii and parts of the Northeast, so scale the last column against your own bill. The method is identical to the one used in what it costs to run an LED bulb for a year: watts times hours divided by 1,000, times your rate.

Why do they draw anything at all?
Because off, for a smart bulb, is a software state rather than an electrical one. The LED emitter is dark, but the driver, the microcontroller and the wireless radio all remain powered so the bulb can hear an instruction. A Wi-Fi bulb has the highest overhead here — maintaining an association with a router and periodically re-authenticating costs more than a Zigbee or Thread bulb sitting quietly on a low-power mesh. Bluetooth-only bulbs draw least of all. Manufacturers almost never publish standby figures, so radio type is the practical guide when you are choosing, and it is a factor in our best smart bulb picks.

Should you cut power at the wall?
Only if the fixture will genuinely not be used for a long stretch — a guest room, a seasonal porch, a vacation empty house. Killing the switch eliminates the draw but also drops the bulb off the network, so schedules stop, automations break, and voice control fails until someone walks over and flips the switch. Many households solve this by removing or covering the switch entirely so nobody turns it off by accident. Where you want real circuit control and network control together, install a smart switch and use ordinary LED bulbs behind it — see how to install a smart light switch. A smart switch also draws a small standby load, typically under a watt, but it covers a whole fixture rather than each bulb in it.

How does it compare with everything else on standby?
Modestly. The Department of Energy has long flagged standby power as a meaningful slice of household electricity use, and the biggest contributors are set-top boxes, game consoles left in instant-on mode, desktop computers, and phone and laptop chargers left plugged in. A cable box alone can idle at 15 to 30 watts, which is fifty to a hundred smart bulbs. If reducing vampire load is the goal, start there. Lighting standby is a rounding error next to what a smart LED saves against the incandescent it replaced, which still runs 50 to 60 watts when on — the US Department of Energy notes that LED lighting is already the most energy-efficient lighting technology available, with efficacies up to 150 lumens per watt or more in some cases.
Does it change whether smart bulbs are worth buying?
Barely. A few dollars a year is a genuine ongoing cost and deserves to be in the calculation, but it is small against the purchase price and against what the bulbs actually deliver — scheduling, dimming, color and voice control. The stronger argument against smart bulbs in some rooms is lifespan rather than standby draw: good-quality white LEDs are rated for a useful life of 30,000 to 50,000 hours or longer, and it is the added radio and driver electronics behind the standby draw that tend to fail first: see how long smart bulbs last. The full value case is in are smart bulbs worth it.
We do not buy, test or physically handle any product on this site — figures here are derived from EIA average electricity prices, Department of Energy standby-power guidance and manufacturer specifications. See how we rank.
More from this hub: Indoor Lighting · Smart bulbs without Wi-Fi · LED bulb lifespan · How we rank
