I am looking trying to figure out if kerosene burns more slowly. If kerosene lasts more than 2 1/2X longer then it would possiblly be more efficient. How can I find that information out? Where I live, propane goes up to about $2 gallon & kerosene is $5 a gallon. We have a kerosene heater that sits on the floor & uses about 2 gallons a day (burns on high for about 10 hours) & that's just supplimenting the central electric units when necessary. I am considering buying 2 propane heater (to suppliment the units... using daily during the winter & also for an emergency source of heat in case of another ice storm & 7 day power outagage) & buying a 250 or 400 gal propane tank (filling it up in the middle of summer when propane is at it's cheapest). It looks like propane is going to be the better, more reliant, cheaper source of heat if kerosene doesn't burn 2 1/2 times longer. Can you advise?