So an oven that is rated at 11,000 watts uses 11 Kilowatts per hour or 11 KWH. The electric company bases their charges on KWH, mine is $.057/KWH. That means my electric oven costs 11 x $.057 = $.63 per hour to run. Propane and Natural Gas ovens are rated in BTU/hour (here anyway). My LP oven uses 60,000 BTU per hour.It takes approximately 1 gallon of propane to burn 90,000 BTU. So my oven uses (60,000/90,000) .67 of a gallon of propane to run for 1 hour. Since propane cost me $2.19 per gallon, my running cost per hour is .67 x $2.19 = $1.46 per hour.Of course these are approximates based on the manufacturer's specs, plus different ovens take longer to heat up than others and retain their heat more or less. There you go.ince propane cost me $2.19 per gallon, my running cost per hour is .67 x $2.19 = $1.46 per hour. Of course these are approximates based on the manufacturer's specs, plus different ovens take longer to heat up than others and retain their heat more or less. There you go.