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LED vs Incandescent Savings

The case for switching to LED bulbs isn't subtle — a 9-watt LED produces the same brightness as a 60-watt incandescent while using 85% less electricity, and lasts 15-25x longer (15,000-25,000 hours vs 1,000 hours). On a house with 20 bulbs running 5 hours a day, that's $80-150 in annual savings at typical electric rates. Over 10 years (longer than most LEDs need replacement), $800-1,500. This calculator runs the math for your specific bulb count, daily usage, electricity rate, and bulb wattages. Stop hand-waving the savings number and see what your house actually saves.

Yearly savings

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10-year savings
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Old kWh / yr
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New kWh / yr
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The math behind the savings

Annual kWh per bulb = (bulb watts × hours per day × 365) ÷ 1,000. Annual cost per bulb = kWh × your electric rate.

Worked example: 20 bulbs, 5 hours/day, $0.16/kWh, swapping 60W incandescent for 9W LED.

  • Old (60W): 20 × 60 × 5 × 365 / 1000 = 2,190 kWh/year = $350/year
  • New (9W): 20 × 9 × 5 × 365 / 1000 = 328 kWh/year = $52/year
  • Annual savings: $298 ($350 – $52)
  • 10-year savings: ~$2,980 (excluding rate increases)
  • Plus avoided bulb replacements: incandescent at 1,000 hours = 1.8 bulbs/year per fixture replaced; LED at 25,000 hours = bulb replacement once per 13.7 years. Avoided bulb costs add another $50-100/year for a 20-fixture house.

LED equivalents for common incandescent wattages

  • 40W incandescent = 5-6W LED (450 lumens)
  • 60W incandescent = 8-9W LED (800 lumens)
  • 75W incandescent = 11-12W LED (1,100 lumens)
  • 100W incandescent = 14-17W LED (1,600 lumens)
  • 150W floodlight = 18-22W LED (2,300 lumens)

Always compare by lumens, not watts. Lumens measure light output; watts measure energy consumption. A high-quality LED at 9W can produce as many lumens as a low-quality LED at 12W — read the label.

How to use this calculator

  1. Number of bulbs: count the fixtures you'd replace.
  2. Hours per day each: typical residential average is 3-5 hours.
  3. $/kWh: from your electric bill. US average ~$0.16/kWh; CA, NY, MA $0.25-0.35; LA, FL, TX $0.10-0.14.
  4. Incandescent watts: typical 60W; some fixtures use 40W or 75W.
  5. LED watts: usually 9W replacement for a 60W incandescent.
  6. Output: annual savings, 10-year savings, and kWh comparison.

Common scenarios

Whole house, 30 bulbs at 60W → 9W LED, 5 hours/day average, $0.16/kWh. Annual savings: $447. 10-year savings: $4,470. LED replacement cost: 30 bulbs at $3-5 each = $90-150. Payback period: 3-4 months.

Small condo, 12 bulbs at 60W, 3 hours/day, $0.30/kWh (California). Annual savings: $200. 10-year: $2,000. LED upfront cost: $50. The high CA electric rate makes the payback nearly instant.

Commercial: small office with 50 bulbs at 75W → 12W LED, 10 hours/day, $0.12/kWh. Annual savings: $1,375. 10-year: $13,750. Plus reduced HVAC cooling load (LEDs produce 75% less heat than incandescents). LED upfront: $250-400. Payback: 2-3 months.

FAQ

Are LED prices still going down? +
Yes, slowly. 2010 LED bulb prices: $30-50 each. 2020: $4-8. 2025: $2-5 for basic 60W-equivalent LEDs at big-box stores. Premium smart LEDs (color-tunable, dimmable, Wi-Fi) run $10-25 each. Multi-packs are cheaper per bulb.
Do LEDs save on air conditioning too? +
Yes, indirectly. Incandescents convert ~90% of input energy to heat (and only ~10% to light). LEDs convert ~25% to heat, 75% to light. In an air-conditioned home, every kWh saved from LED replaces some cooling load — effectively a 1.1-1.4x multiplier on electricity savings in cooling-dominated climates.
What about CFLs? +
CFLs (compact fluorescent) were the bridge technology — 75% more efficient than incandescent, 25% less efficient than modern LED. They contain mercury, take 30-60 seconds to warm up, don't dim well, and last only 8,000-10,000 hours. Newer LEDs beat CFLs on every dimension. Skip CFLs; go LED.
Why do some LEDs flicker on dimmer switches? +
Most LEDs require specific "LED-rated" dimmer switches (trailing-edge / ELV dimmers). Old-style triac / leading-edge dimmers from incandescent days don't fully cut off the AC waveform, causing visible flicker or strobe. Replace the dimmer ($25-50) when upgrading bulbs to dimmable LEDs. Look for "LED+ Compatible" on the dimmer packaging.
Why is one LED bulb cool white and another warm white? +
Color temperature in Kelvin. 2700K = warm white (like incandescent). 3000K = soft white. 4000K = neutral. 5000-6500K = daylight / cool white. For homes, 2700-3000K matches the look most people are used to. 4000K+ feels institutional and cool — OK for garages and workshops, harsh in living rooms.
Do LEDs work in enclosed fixtures? +
Some yes, some no — the package will say "enclosed fixture rated" if it is. Non-rated LEDs in enclosed fixtures overheat and die in 1-2 years instead of 10+ years. Premium LEDs (Cree, Philips) typically rate for enclosed fixtures; very cheap LEDs often don't.
What about smart LEDs? +
Smart bulbs (LIFX, Philips Hue, IKEA Trådfri) cost $10-30 each, integrate with Alexa/Google/Apple Home, and offer color control. They use slightly more standby power than dumb LEDs (~0.5W vs ~0.05W when "off") but the convenience of automation is huge. For high-use rooms (living room, kitchen): worth it. For closets and basements: dumb LED is fine.
Will my old incandescent bulbs work until they burn out, or should I replace immediately? +
Replace immediately. The energy savings of an LED in 1-2 months exceeds the cost of the new bulb. The longer you keep an incandescent in service, the longer you're paying premium rates. Make swapping a Saturday-morning sweep through the house.