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Solar Collector Estimator

Select Category Input # Results  
  Hot Water Daily Consumption (Gal)
Select State Daily Energy Required in BTU
  Daily Energy Required in Therms
Energy Assessment Data Renewable Energy Savings  
Hot Water Temperature out (F) Total Annual Energy Fuel Units Saved
Ground Water Temperature in (F) Total Annual Pounds Of CO2 Saved
Collector BTU (if known) Costs  
Collector sq. ft. (if known) Solar Thermal System Price (est.)
Energy Source (Gas, Kwh, Lp, Oil) Estimated Installation
Energy Source Rate Per Fuel Unit $ State Tax
Your Federal Tax Rate for Depreciation Total System Installed Value
Your business has "non-profit" status State Rebate
  Federal Tax Credit - (30% of installed cost)
System Components   Possible 179 Deduction *
Flat Plate Collectors Federal Tax on State Rebate *
Total Absorbing Surface Possible MACRS State Depreciation *
Output per Collector Total Estimated Net Cost
Total Daily BTU Output Estimated Annual Savings $
Minimum Storage Tank (Gal) ROI (Return on Investment) Years
Maximum Storage Tank (Gal) * Check with your accountant  

Solar Calculator Notes:
Input yellow fields and tab through for results!

Costs listed above are Estimated Retail Costs! Free Hot Water sells only to distributors and contractors and costs many vary.

The numbers above should be used as an estimation; your location, climate, age of existing water heater, building height and use may change the numbers. Free Hot Water is not responsible for the accuracy of the calculator.

Enter any flat-plate collector BTU and sq. ft. – Collector listed above is the 4×10 – 8000 series:

  • (FHW 7000 Series, 28,400 BTU, 27.67 Sq. ft.)
  • (FHW 8000 Series, 42,400 Btu’s, 40 sq. ft.)
  • (FHW 5000 Series, 23,100 BTU’s, 22.28 sq. ft.)
  • (FHW 4000 Series, 21,500 BTU’s, 21.86 sq. ft.)

Energy Source, enter “Natural Gas”, “Electric-kwh”, or “Propane-LP” and rate.
The Federal Tax rate calculates the depreciation schedule. A “non-profit” business cannot claim a Federal Tax Credit.

We try to stay up-to-date on all the state rebate programs, let us know if we need to update your state.

Please contact us with any questions. If you would like this calculator on your site, just ask and we’ll help you with the code.