LED Savings Calculator

The core is the wattage drop. Multiply the watts saved per fixture by the number of fixtures and the hours they run each year to get kilowatt-hours saved, then multiply by your electricity rate. Swapping forty 60 W bulbs for 9 W LEDs at 10 hours a day, for example, saves a lot of kWh a year. This calculator does the full version: it adds the money saved on bulb replacements and labor, an optional cooling-load credit, and any rebates, then reports the year-one saving, payback, and net return over your chosen period.

Match on brightness (lumens), not wattage, since LEDs produce the same light for far less power. As rough equivalents, a 60 W incandescent is about a 9 W LED, a 75 W is around 11 W, and a 100 W is roughly 15 W — each delivering similar lumens. Halogens are close to incandescent, while CFLs already use less, so the LED saving over a CFL is smaller. Enter the actual LED wattage from the product you’re considering for the most accurate result.

Energy is only part of the story. An incandescent might last around 1,000 hours while an LED lasts 25,000, so over the same period you buy — and change — far fewer bulbs. Each change costs the price of a bulb plus the time to swap it. In hard-to-reach or paid-labor settings, that avoided maintenance can rival the energy saving. The calculator prorates replacements per year for both the old and new bulbs, so the comparison reflects the true cost of ownership, not just the meter.

Old bulbs waste much of their energy as heat, and in an air-conditioned space that heat has to be removed — so cutting lighting wattage also lightens the AC’s workload. The cooling credit adds that secondary saving as a percentage of your lighting energy savings; a typical cooled commercial space sees somewhere in the range of 5–15%. Leave it at zero for unconditioned areas, or in winter-dominated climates where lamp heat partly offsets heating. It only adds savings where you’re actually paying to cool the space.

The calculator adds up the LED product cost and installation, subtracts any utility rebates to get a net upfront cost, then tracks cumulative savings year by year. Payback is the point where those savings have repaid that upfront cost — the schedule flags the exact break-even year. ROI is the net saving over the whole analysis period divided by the upfront cost, expressed as a percentage. Because it raises your rate by the annual increase you set, later years save a little more, which is why longer-run fixtures reach payback fastest.

LED rebates are mostly offered by electric utilities rather than the federal government, and they vary widely by provider and program, so confirm what’s current before relying on a figure. Many utilities pay a few dollars per qualifying fixture — often more for commercial or high-efficiency products — and some run instant point-of-sale discounts at retailers. Check your utility’s rebate portal or the ENERGY STAR rebate finder with your ZIP code, note the per-fixture amount and any product requirements, then enter that amount in the calculator so your payback reflects what you’ll actually pay.