Operating Cost and Spreadsheet

							                    Tmonter's Water Heater Operating Cost Spreadsheet
                        Item             Units       Value
Well or City Water Temperature             °F         50      Enter Cold Water Temperature
Water Heater Set Point                     °F         125     Enter Water Heater Set Temperature
Energy to heat 1 pound of water            Btu       622.5


Estimate daily hot water usage           gallon(s)    100     Enter Daily Hot Water Usage in Gallons

Electricity Price                        $/kW-hr     $0.120   Enter Electricity Price
Electricity price calculated             $/MMBtu     $35.17
Natual Gas Price                          $/therm    $1.43    Enter Natural Gas Price
Gas Price Calculated                     $/MMBtu     $14.30


Initial Cost of New Water Heater            $         1400    Enter Installed Cost
Daily cost of original unit to operate      $        $3.00    Enter Original Heater Operating Cost


Water Heater - Gas Tank
Efficiency                                  %         65%     Enter Efficiency of Unit
Standby losses - estimated                  %         10%
Price per MMBtu Utilized to operate      $/MMBtu     $24.20
Daily Cost to operate                       $        $1.51
Payback period                            Years       2.57    Payback time versus original unit

Water Heater - Electric Tank
Efficiency                                  %         95%     Enter Efficiency of Unit
Standby losses - estimated                  %         10%
Price per MMBtu Utilized to operate      $/MMBtu     $40.72
Daily cost to operate                       $        $2.53
Payback period                            Years       8.25    Payback time versus original unit

Water Heater - Gas On Demand
Efficiency                                  %         82%     Enter Efficiency of Unit
Standby losses                              %         0%
Price per MMBtu Utilized to operate      $/MMBtu     $17.44
Daily Cost to operate                       $        $1.09
Payback period                            Years       2.00    Payback time versus original unit

Water Heater - Electric on Demand
Efficiency                                  %         98%     Enter Efficiency of Unit
Standby losses                              %         0%
Price per MMBtu Utilized to operate      $/MMBtu     $35.89
Daily Cost to operate                       $        $2.23
Payback period                            Years       5.01    Payback time versus original unit