Infern-O-Therm Stack Economizer Savings Calculator

This calculator computes fuel savings and potential return on investment for an Infern-O-therm Stack Economizer retrofit kit. The IOT Stack Economizer, which uses flu exhaust gases to pre-heat incoming water, will fit most makes of direct-fired water heating tanks. In this calculator, we use two popular sizes of Infern-O-Therm burners, models 300 and 400. Tests have shown that the 400, with twice the output of the 300, derives the greater benefit from flu heat recovery, and will show a shorter ROI. Finally, we've left labor costs at zero because of the wide variation from one producer to the next. Fill in your estimated labor cost for a better ROI estimate. (Results appear below the "calculate" button row.)

Assumptions:

1. Oil = 138,500 BTU/gal 2. Calculations based on 8-hour days, 5 days per week.