Last updated: October 2026
One of the oddities of smart bulbs is that “off” doesn’t mean fully off. To respond instantly when you say “Alexa, turn on the lamp,” the bulb has to stay awake and connected. That standby draw is small, but if you’re lighting a whole home it’s fair to ask what it costs. Here are the real numbers, and how to keep them low.
Why Do Smart Bulbs Use Electricity When Off?
A smart bulb contains a tiny radio (Wi-Fi, Bluetooth, Zigbee or Thread) and a small controller. When you switch the light “off” in the app, only the LEDs turn off; the radio stays powered so the bulb can hear the next command. That always-listening state is called standby power.
If you switch the bulb off at the wall, it’s truly off and draws nothing, but it also can’t respond to Alexa or the app until the switch is turned back on.
How Much Standby Power Do Smart Bulbs Use?
Most modern smart bulbs draw well under one watt in standby, with many in the range of a few tenths of a watt. Wi-Fi bulbs tend to draw slightly more than Zigbee or Thread bulbs, because Wi-Fi radios are hungrier. Exact figures vary by model and are sometimes listed in the bulb’s specifications.
Our explainer comparing Zigbee vs Wi-Fi smart bulbs goes deeper into why the radio type affects power use.
What Does Smart Bulb Standby Power Cost per Year?
For a single bulb, standby power typically costs well under a dollar a year. Across 20 bulbs, you might spend something in the range of ten dollars a year on standby, depending on the models and your electricity rate. It’s real, but small compared with the energy LEDs save over old bulbs.
| Standby draw | Per bulb per year* | 20 bulbs per year* |
|---|---|---|
| 0.2 W | ~$0.25 | ~$5 |
| 0.5 W | ~$0.60 | ~$12 |
| 1.0 W | ~$1.20 | ~$24 |
*Assumes about 20 hours a day in standby at $0.17/kWh. Check your own utility rate.
Do Smart Bulbs Still Save Energy Overall?
Yes, compared with incandescent or halogen bulbs. An 800-lumen smart LED uses about 9 watts when on, versus 60 watts for the incandescent it replaces. Over a few hours of daily use, that difference dwarfs the standby cost. Schedules and auto-off routines also stop lights being left on in empty rooms.
Compared with a regular non-smart LED, a smart bulb does use slightly more energy overall because of standby. You’re paying a small amount for convenience and automation, which most people find worthwhile.
How Can You Reduce Smart Bulb Standby Power?
Use smart bulbs only where automation adds real value, choose efficient Zigbee or Thread bulbs for large setups, and consider a smart switch where many bulbs share one fixture. Turning off seldom-used lamps at the wall also removes standby completely.
- Be selective: put smart bulbs in rooms where you actually use schedules or voice control.
- One switch, many bulbs: a single smart switch for a six-bulb ceiling fixture uses less standby than six smart bulbs.
- Choose efficient radios: Zigbee and Thread typically sip less power than Wi-Fi.
- Cut power to unused lamps: guest rooms and seasonal lights can be switched off at the wall.
Looking for efficient picks that work without extra hardware? See our best smart bulbs without a hub, or read whether smart bulbs need a hub before you decide.
Frequently Asked Questions
Do smart bulbs use power when the light switch is off?
No. With the wall switch off, the bulb has no power at all, so it uses nothing and also can’t receive commands. Standby power only applies when the switch stays on and you turn the light off through the app or a voice assistant.
Is it bad to leave smart bulbs in standby all the time?
No, that’s how they’re designed to work. Standby draw is small and the bulbs are built to stay connected continuously. Leaving the wall switch on is necessary for app and voice control.
Do Wi-Fi smart bulbs use more standby power than Zigbee?
Generally yes. Wi-Fi radios use more power to stay connected than Zigbee or Thread radios. The difference per bulb is small, but it becomes more noticeable in homes with dozens of smart bulbs.
Will smart bulbs increase my electricity bill?
Slightly compared with regular LEDs, because of standby power, but usually by only a few dollars a year for a typical home. Compared with old incandescent bulbs, smart LEDs still cut your lighting costs significantly.
How can I check how much power my smart bulb uses?
Plug a lamp with the smart bulb into an energy-monitoring smart plug or a plug-in power meter. It will show watts when the bulb is on and in standby. Some bulb specification sheets also list standby power.
The Bottom Line
Smart bulbs do use a little electricity when “off,” usually a fraction of a watt, costing well under a dollar per bulb per year. Compared with old bulbs they still save energy, and being selective keeps standby to a minimum. For efficient, hub-free options, start with our best smart bulbs without a hub.