Chemical Basics

• Propane's chemical formula is C3H8, and it has a boiling point of -44 degrees Fahrenheit. Kerosene doesn't have a specific chemical formula, since its comprised of a number of different hydrocarbons and stray compounds. Kerosene is more of a liquid paraffin wax than a pure fuel like propane, which is why it's generally referred to as paraffin oil in the UK.
  
  

Heating Values

• The simplest way to assess a substance's energy potential per unit volume is to use the standard British Thermal Unit. One BTU is equal to the amount of energy required to heat one pound of water from 39 degrees to 40 degrees Fahrenheit. One gallon of kerosene contains about 135,000 BTU, which is about 47 percent more than the same quantity of propane (about 91,600 BTU).
  
  

Cost Efficiency

• Kerosene may contain about 47 percent more energy per gallon than propane, but it also costs more in many places. From 2010 to 2011, the going price of kerosene in New York state averaged about $3.80 a gallon, or roughly the same as diesel. As of March 2011, it has hit $4.25 a gallon. Compare this to propane, which is currently going for about $2.90 a gallon; so, at present, you'd be paying 46 percent more for a fuel that's only 47 percent more efficient.
  
  

Price Fluctuation

• One more thing to bear in mind where propane is concerned is that it tends to fluctuate at about the same rate as diesel; kerosene increased in price by about 28 percent from 2010 to 2011, compared to propane's one percent over the same period of time.
  
  

Comparison

• Kerosene has three major advantages over propane: it's safer to store, anything using it can also utilize heating oil or possibly even diesel, and it might be cheaper if you live in an area where propane is expensive and fuel oils are cheap. However, like all heavy oils, kerosene can turn to gel in very cold weather, and it does go bad if stored for months or years. This means that the kerosene you bought in February might have gone bad by December. You could add a fuel preservative, but that will probably kill whatever cost savings you might have otherwise had. Propane's advantages are that it produces little to no smoke or odor while burning, that it stores indefinitely and that it won't spill while refilling or transporting.