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SED Associates Corp Consulting Engineers Option 8- Direct Replacement Oil -Fired The existing water heater at this location is an oil -fired water heater with a firing rate input of 700,000 BTUH and a maximum recovery rate of 665 GPH at 100°F temperature rise. The tank has a capacity of 120 gallons. This unit, as well as its replacement has an efficiency of 80%. Based on the standard calculation for heating water, 406,575 BTUH are required. (390 GPH * 8.34 lbs/Gal * (140°F -40°F)) * 1.25 = 406,575 BTUH An estimated operation cost based on an estimated cost of $3.20/gallon is $ 8,628.20 Approximate Construction Cost: $30,000 Summary The operational costs provided are for maximum water use, which most likely not be the case. However, to provide an actual operational cost, accurate hot water usage would need to be provided. This would require the metering of the cold -water service that feeds the water heater be installed and recorded for a complete season. Even though the operational cost given in this review of different water heating sources may not reflect the actual cost being realized at this facility, the ratio between the different option's operational cost will remain the same and are: Oil (Base Cost): 1.00 Elec. Tank: 2.43 Elec. Instant: 2.43 Heat Pump: 0.58 CO2 Heat Pump: 0.34 Based on the provided oil usage for the past year (-400 gallons) and a nominal $3.20/gallon the operational cost for the reviewed options range from $3,296 to $8,628, see attached table. Although the CO2 heat pump option shows the lowest operational cost, the simple payback, based on the listed estimated installation cost is —44 years. Therefore, it is our opinion that this is not a viable option when the total installation cost, which would include unknown utility cost and building modification, would most likely drive this payback well of 100 years. Based on the above, it is our recommendation that heater be replaced with Option 3 Solar Assisted Heat Pump. If you have any questions or comments, please contact our offices at (617) 350-7245 or Rcalhoun(a)-sedac.com (e-mail). By: Rick Calhoun Attachments, Table 1, Solar Heat Pump Selection & Solar Hot Water Heater Selection