ROI Calculator

Step 1: Compute the total power (kilowatts, kW) saved by upgrading older Bulbs to energy saving LED replacements

Original Bulb Wattage Replacement Bulb Wattage Watts saved per bulb
Number of bulbs to replace Total watts saved Total kilowatts saved

Step 2: Compute the total energy (kilowatt hours, kWh) saved annually by performing this upgrade

Total Kilowatts saved Hours of use per day Days of use per week
Week of use per year Total kwh saved per year  

Step 3: Compute the total energy cost savings per year

Total kWh saved per year Energy cost per KWH is Rs Total energy cost saving per year in Rs

Step 4: Compute the lifetime energy cost savings

Replacement bulb life in hours Hours per year usage Your energy cost per KWH
Lifetime energy cost saving

Step 5: Simple payback on energy consumption

Initial cost of LED bulb Number of LED bulbs Total energy cost saving per year
No of years paypback

Step 6: ROI

Step 7: Compute the lifetime labor/inventory/acquisition costs savings from upgrading to longer life LED replacements

Replacement bulb hours Existing bulb life hours Labour cost to change existing bulb
Total labour cost for changing bulbs Cost of existing bulb No of bulb to replace
Total cost for replacement bulbs Total lifetime bulb changing cost saving  

Step 8: Compute the amortized bulb changing cost savings per year

Total life time replacement cost Total lifetime of LED Total replacement cost

Step 9: Simple paypack on energy consumption plus replacement cost

Intilal cost of lighting upgrade Total energy saving cost plus replacement cost saving Payback period

ROI on investment