Well @swampratt? There are 91,600 BTUs in a gallon of propane. Just looked it up and according to Google gas furnaces range from 40-200,000BTUs so 91,600/75,000=1.22 hours per gallon and say you’re paying $3.00/gallon if it’s running 50% of the time you’d be looking at around $60/day?? Now my math could be WAY off because I have no idea how large a furnace you’d need and really no clue how long it would have to run to maintain a particular temperature. One of our HVAC guys needs to chime in.
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