Smart Bulb Energy Savings Calculator
See how much money and energy you save each year by swapping an incandescent or halogen bulb for a smart LED — per bulb and across the whole house.
How it works
kWh saved/yr = (old W − LED W) × hours/day × 365 ÷ 1000 · Saving = kWh × rate × bulbs
A smart LED does the same lighting job as an old incandescent or halogen bulb while drawing a fraction of the power, so almost the entire wattage difference becomes saving. Multiply the watts you cut by how many hours the bulb burns each day, scale to a year, and convert to kilowatt-hours by dividing by 1,000. The smart features (scheduling, dimming, presence-off) trim the runtime further, but even on lighting alone the wattage gap dominates the payback.
Worked example
Swapping ten 60 W bulbs for 9 W smart LEDs cuts 51 W each. At 4 hours a day that is 51 × 4 × 365 ÷ 1000 = 74.5 kWh per bulb, or 745 kWh across ten bulbs. At $0.17/kWh you save about $127 a year.
Frequently asked questions
Do smart bulbs use power when off?
Yes — a smart bulb keeps its Wi-Fi or Zigbee radio alive in standby, typically 0.2–0.5 W. Across a dozen bulbs that is a watt or two, tiny next to the tens of watts each one saves while lit, so it barely dents the numbers here.
What electricity rate should I enter?
Use the total per-kWh cost from a recent bill, including delivery and taxes, not just the supply rate. In the US that is often $0.14–$0.25/kWh depending on the state.
Does this include the bulb purchase cost?
No — this is the ongoing energy saving only. Smart bulbs cost more upfront, but the annual saving shown here usually pays that back within a year or two for bulbs that run several hours a day.
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This calculator is for educational purposes. Double-check important results before acting on them.