A simple program to calculate LED lights savings (Output). Full article at http://firsttimeprogrammer.blogspot.com/2014/10/a-simple-program-to-calculate-led.html

LED_savings.py

# Name: MyOffice1. Plant type: Private. Energy cost: 0.18euro/kw 
#
# LED lights data:
# 200 LED Tube 1200mm 18.0 watt. Working hours: 10.0. Days a year: 320
#
# Old lights data:
# 200 Neon Tube 1200mm 36.0 watt. Working hours: 10.0. Days a year: 320
#
#
# Total old lights consumption: 23040.0 kw/year
# Total LED lights consumption: 11520.0 kw/year
# Savings with LED lights (annual, excluding maintenance): 50.0%
# Equivalent to an annual money savings of: 2073.6 euro/year 
#
#
# Total savings at year 10 (euro/year): 2073.6
# Total savings at year 9 (euro/year): 2473.6
# Total savings at year 8 (euro/year): 2073.6
# Total savings at year 7 (euro/year): 2073.6
# Total savings at year 6 (euro/year): 2473.6
# Total savings at year 5 (euro/year): 2073.6
# Total savings at year 4 (euro/year): 2073.6
# Total savings at year 3 (euro/year): 2473.6
# Total savings at year 2 (euro/year): 2073.6
# Energy savings at year 1 (euro): 2073.6
#
# LED lights cost: 5200.0 euro.
# Installation costs: 0 euro.
# Amortization in 2.51 years. (Considering consumption savings only).
#
###################################################################
# Annual payment due: 1466.46 euro
# Annual immediate savings: 607.14 euro
# Interest rate applied 5.0%
# Number of payments (years): 4