## 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 1.5 gallons per min = 45 |

## step 3 find the difference in gallons used75 - 45 = 30 gallons savings |

## step 4 find the cost savings in water30 x $0.0056 = $0.1680 water savings per day |

## step 5 find the number of heated gallons of water75 x 60% = 45 gallons of heated water per day 45 x 60% = 27 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 27 gallons to heat = 21,847.8438 BTUs per day |

## step 10 convert BTUs to therms36,413.0730 / 100,000 = 0.3641 therms per day 21,847.8438 / 100,000 = 0.2185 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 0.2185 therms per day x 29.3071 KWh per therm = 6.4036 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 6.4036 daily KWh use * $0.118 cost per KWh = $0.7556 per day cost |

## step 13 find the difference in electric savings$1.2591 - $0.7556 = $0.5035 electric savings per day |

## step 14 add the water and electric savings$0.5035 daily electric savings + $0.1680 daily water savings = $0.6715 daily savings |

## step 15 find yearly and lifetime savings in dollars with electric$0.6715 x 365 = $245.10 yearly savings with electric $245.10 x 15 year estimated life = $3,676.46 estimated lifetime savings with electric |

## step 16 find yearly and lifetime electric savings10.6707 - 6.4036 = 4.2671 daily KWh savings 4.2671 x 365 = 1,557.5 yearly KWh savings 1,557.5 x 15 year estimated life = 23,362 lifetime KWh savings |

## step 17 find yearly and lifetime water savings30 gallons daily water savings x 365 = 10,950 gallons yearly water savings 10,950 x 15 year estimated life = 164,250 lifetime water savings $0.1680 daily water savings x 365 days = $61.32 yearly water savings |