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