## showerhead savings calculations

### how your savings are calculated

## step 1 find cost per gallon$2.80 fresh water + $2.80 waste water = $5.60 per 1000 gallons $5.60 / 1000 = $0.0056 per gallon |

## step 2 find daily gallon usage30 mins x 2.5 gallons per min = 75 30 mins x 2.2 gallons per min = 66 |

## step 3 find the difference in gallons used75 - 66 = 9 gallons savings |

## step 4 find the cost savings in water9 x $0.0056 = $0.0504 water savings per day |

## step 5 find the number of heated gallons of water75 x 60% = 45 gallons of heated water per day 66 x 60% = 39.6 gallons of heated water per day |

## step 6 find the number of degrees of heating water140 water heater temp - 57.5 cold water temp = 82.5 degrees |

## step 7 multiply the number of degrees by the 8.337 BTUs it takes to heat one gallon of water one degree8.337 BTUs x 82.5 degrees to raise by = 687.8025 BTUs to heat 1 gallon to desired temp |

## step 8 take into account the hot water heater efficiency687.8025 BTUs / 85% = 809.1794 |

## step 9 multiply your efficiency adjusted BTUs by the number of gallons to be heated809.1794 BTUs x 45 gallons to heat = 36,413.0730 BTUs per day 809.1794 BTUs x 39.6 gallons to heat = 32,043.5042 BTUs per day |

## step 10 convert BTUs to therms36,413.0730 / 100,000 = 0.3641 therms per day 32,043.5042 / 100,000 = 0.3204 therms per day |

## step 11 covert therms to kilowatt hours for electric water heaters0.3641 therms per day x 29.3071 KWh per therm = 10.6707 KWh per day 0.3204 therms per day x 29.3071 KWh per therm = 9.39 KWh per day |

## step 12 find the cost of heating water with electric10.6707 daily KWh use * $0.118 cost per KWh = $1.2591 per day cost 9.39 daily KWh use * $0.118 cost per KWh = $1.1080 per day cost |

## step 13 find the difference in electric savings$1.2591 - $1.1080 = $0.1511 electric savings per day |

## step 14 add the water and electric savings$0.1511 daily electric savings + $0.0504 daily water savings = $0.2015 daily savings |

## step 15 find yearly and lifetime savings in dollars with electric$0.2015 x 365 = $73.55 yearly savings with electric $73.55 x 15 year estimated life = $1,103.21 estimated lifetime savings with electric |

## step 16 find yearly and lifetime electric savings10.6707 - 9.39 = 1.2807 daily KWh savings 1.2807 x 365 = 467.5 yearly KWh savings 467.5 x 15 year estimated life = 7,012 lifetime KWh savings |

## step 17 find yearly and lifetime water savings9 gallons daily water savings x 365 = 3,285 gallons yearly water savings 3,285 x 15 year estimated life = 49,275 lifetime water savings $0.0504 daily water savings x 365 days = $18.40 yearly water savings |