Lighting Retrofit ROI Calculator
LED retrofits remain one of the fastest-payback efficiency investments available to a commercial or industrial facility — replacing older metal halide or fluorescent fixtures with LED equivalents cuts connected lighting load dramatically while typically lasting 3-5x longer. This calculator takes your fixture count, existing and LED wattages, operating hours, electricity price, installed cost per fixture, and available utility rebate per fixture, then reports the total wattage reduction, annual energy and cost savings, net project cost after rebates, and the simple payback period. For a single-fixture, home-scale comparison, see the LED Lighting Savings Calculator, and to benchmark an existing building's overall energy use against national medians, see our Building Energy Benchmark Calculator.
Total count of fixtures being retrofitted across the project.
Common for older metal halide high-bay fixtures.
Typical LED high-bay equivalent replacement for a 400W metal halide fixture.
Annual hours the fixtures are energized. Warehouses and manufacturing floors often run 4,000-8,000 hours/year.
Commercial and industrial electricity rates vary by region and rate schedule.
All-in installed cost per fixture — fixture, lamp/driver, labor, and any electrical work.
Many utility programs offer $20-50 per fixture in LED retrofit rebates — check your specific utility's current program.
(existing fixture wattage (W) − LED replacement wattage (W)) × number of fixtures ÷ 1,000
total wattage reduction (kW) × operating hours per year
annual energy savings (kWh) × electricity price ($/kWh)
(cost per fixture installed ($) × number of fixtures) − (rebate per fixture ($) × number of fixtures)
net project cost ($) ÷ annual cost savings ($/year)
Results update live as you type. For planning and field-check estimates — always verify against applicable standards and equipment ratings.
How we calculate this →LED retrofits remain one of the fastest-payback efficiency investments available: replacing 200 high-bay fixtures from 400W metal halide to 150W LED cuts connected lighting load by 50 kW, saving $24,000 a year in energy costs at $0.12/kWh. With typical utility rebates offsetting installation cost, this project pays for itself in exactly 1 year in this example -- and LED fixtures typically last 3-5x longer than the metal halide or fluorescent technology they replace, adding maintenance savings on top of the energy savings this calculator captures.
How lighting retrofit ROI is calculated
This calculator ties the energy savings, project cost, and payback period of a commercial LED lighting retrofit to seven inputs: the number of fixtures, the existing fixture wattage, the LED replacement wattage, the annual operating hours, the electricity price, the installed cost per fixture, and the available utility rebate per fixture. Five quantities tie the calculation together.
Wattage Reduction per Fixture (W) = Existing Fixture Wattage (W) − LED Replacement Wattage (W). LEDs convert a much higher share of input electricity directly into usable light rather than heat, so an LED replacement delivers comparable light output at far lower wattage; replacing a 400W metal halide high-bay with a 150W LED equivalent cuts 250W per fixture. Total Wattage Reduction (kW) = (Wattage Reduction per Fixture (W) × Number of Fixtures) ÷ 1,000; dividing by 1,000 converts watts to kilowatts, and at 250W per fixture across 200 fixtures that is (250 × 200) ÷ 1,000 = 50 kW of connected lighting load removed.
Annual Energy Savings (kWh) = Total Wattage Reduction (kW) × Operating Hours per Year. Energy is power sustained over time, so kilowatts × hours gives kilowatt-hours — the unit your utility bills. At 50 kW and 4,000 hours/year, that is 50 × 4,000 = 200,000 kWh saved annually. Operating hours are the single most decision-relevant input: a facility running 8,000 hours/year saves twice the energy of one running 4,000 hours with identical fixtures, doubling the annual dollar savings and halving the payback period.
Annual Cost Savings ($/year) = Annual Energy Savings (kWh) × Electricity Price ($/kWh); at 200,000 kWh and $0.12/kWh, that is 200,000 × 0.12 = $24,000 per year. Total Project Cost ($) = Cost per Fixture (Installed) ($) × Number of Fixtures; at $150 per fixture across 200 fixtures, that is $150 × 200 = $30,000. Total Rebate ($) = Available Rebate per Fixture ($) × Number of Fixtures; at $30 per fixture across 200 fixtures, that is $30 × 200 = $6,000. Net Project Cost ($) = Total Project Cost ($) − Total Rebate ($); at $30,000 and $6,000, that is $30,000 − $6,000 = $24,000 — the actual out-of-pocket project cost after utility rebates are applied.
Simple Payback Period (years) = Net Project Cost ($) ÷ Annual Cost Savings ($/year); at a $24,000 net project cost and $24,000/year in savings, that is $24,000 ÷ $24,000 = 1.0 year. Two notes on the model. First, it captures only energy cost savings and payback from the project cost alone — it does not account for maintenance savings from LEDs lasting 3-5x longer than the metal halide or fluorescent technology they replace, which reduces relamping labor and material costs and is an additional benefit on top of the energy savings shown here. Second, it assumes the LED replacement delivers comparable light output to the existing fixture at the entered wattage; real fixture selection should verify lumen output, light distribution, color temperature, and dimming/control compatibility against the application's requirements. Data sources: LED vs. metal halide/fluorescent wattage comparisons from manufacturer specifications and DOE lighting efficiency data; commercial lighting retrofit payback analysis from utility rebate programs and energy audit case studies; LED fixture lifespan data from manufacturer specifications and IESNA standards; electricity rates from EIA commercial/industrial data.