This LED savings calculator prices the bulb swap: watts saved per bulb × hours × your rate — yearly savings, bulb-cost payback, and the decade view.

kWh Saved / Year–
Savings / Year–
Payback Period–
10-Year Net Saving–

Match lumens, not watts, when choosing replacements (≈800 lm replaces a 60 W incandescent). The hidden second dividend: incandescents die every ~1,000 hours (you’d buy ~9 more per socket this decade); LEDs run 15,000–25,000 — avoided replacements widen the 10-year figure beyond what’s printed here.

ΔWatts × Hours × Days — Small Numbers, Compounded Honestly

Lighting is the rare retrofit whose math works in every home; the rest of the electrical herd is itemized on our Appliance Energy Calculator. Part of our Ecology Calculators collection.

Worked Example (Verified)

  • 10 bulbs, 60 W → 9 W, 5 h/day, $0.17 (defaults): 931 kWh saved/yr → $158/year, bulbs pay back in ~2 months, 10-year net ≈ $1,556 — the best legal return on $25 in home economics
  • CFL → LED is the smaller sequel: 14 → 9 W saves 5 W/bulb; the same 10 bulbs at 5 h save $15.50/yr — worth doing at replacement time, not as an emergency
  • The closet-bulb fallacy: a bulb on 15 min/day saves ~$1.60/yr swapped — prioritize by hours (kitchen, living room, exterior) not by socket count
  • Brightness equivalence table for shopping: 40 W ≈ 450 lm (6 W LED), 60 W ≈ 800 lm (9 W), 75 W ≈ 1,100 lm (12 W), 100 W ≈ 1,600 lm (15 W)

Choosing Bulbs That Deserve the Math

  • Color temperature: 2700 K mimics incandescent warmth; 3000–4000 K for kitchens/workspaces; consistency across a room matters more than the exact K.
  • CRI 90+ renders colors honestly (art, makeup, food) — cheap 80-CRI bulbs save watts and spend ambiance.
  • Enclosed-fixture and dimmer compatibility are the two failure modes; check the box icons before buying 20.
  • Exterior/cold locations favor LED doubly: instant full brightness where CFLs sulked.

Related Tools

Frequently Asked Questions

How much do LED bulbs save?

Per bulb: (old watts − LED watts) × hours × 365 ÷ 1000 × your rate. A 60 W → 9 W swap at 5 h/day and $0.17/kWh saves ~93 kWh = $15.80 per bulb per year. Ten bulbs: $158/year with payback in about two months at $2.50 per bulb.

What LED replaces a 60W incandescent?

An ~800-lumen LED, typically 8–10 W. Match lumens (brightness), never watts — wattage measures appetite, not output. Equivalents: 450 lm ↔ 40 W, 1,100 lm ↔ 75 W, 1,600 lm ↔ 100 W incandescent.

How long do LED bulbs last?

Rated 15,000–25,000 hours (vs ~1,000 incandescent, ~8,000 CFL): at 5 h/day that's 8–14 years. Real life shortens it with heat (enclosed fixtures) and cheap drivers — which is why the 10-year savings here also silently include ~9 avoided incandescent replacements per socket.

Is it worth replacing CFLs with LEDs?

Eventually, at natural replacement: the incremental saving is small (~5 W/bulb) but LEDs add instant-on, dimming range, no mercury, and cold-weather performance. Don't landfill working CFLs for it — swap on failure, high-hour sockets first.

Do LEDs save on cooling too?

Yes, in cooling season: 85% of an incandescent's watts become room heat your AC must then remove (adding up to ~30% more saving on those hours in hot climates); in heating season the effect reverses trivially — the bulb was a tiny, inefficient space heater with a lighting hobby.

Is this LED savings calculator free?

Yes — free, instant, no sign-up.