How to Calculate Furnace Oil Consumption
Knowing the fuel consumption of your oilburning furnace can tell you how long a tank of fuel oil will last. Knowing when you will need a tank refill can help with budgeting heating costs and timing your heating fuel deliveries. If you know your present fuel consumption, you can track the benefits of furnace tuneups and insulation improvements. You can calculate a rough estimate of your furnace oil consumption with basic math and a few pieces of information..

Look on your oil burner for a manufacturerâ€™s data plate. Look on the plate for the gallons per hour this furnace is designed to use. Or look on the burner nozzle for a number that tells the gallons per hour for the installed nozzle. The gallonsperhour figure refers to oil consumption while the burner is actually in operation. Typical home oil furnaces consume between 0.8 and 1.7 gallons per hour of operation.

Observe oil burner operation for one hour during the middle of the day when outdoor temperatures are highest. Track the minutes that the burner is actually running during that hour with the clock or watch. Observe operation for one hour sometime between 3 a.m. and 6 a.m. when outdoor nighttime temperatures are lowest. Track the minutes when the burner is actually running in the coldest hour. Make both observations on the same day.

Average the two observations, and multiply the result by 24 to get the number of minutes per day your burner is running. Then divide by 60 to translate minutes per day into hours per day. For example, if the burner operated for 25 minutes during the warm midday hour and 40 minutes during the cold nighttime hour, add 25 to 40 and divide the result by 2 to get an average 33 minutes per hour of burner operation. Multiply 33 by 24 hours to get 792 minutes of burner operation per day. Divide 792 by 60 to get 13 hours per day of burner operation.

Multiply the hours of burner operation by the gallons per hour to find out the gallons per day your furnace will use. For instance, if your oil burner uses 1.7 gallons per operating hour and it runs for 13 hours per day, it will burn 22 gallons per day. Divide the capacity of your fuel tank by the gallons per day to find out how long the tank will last. If you have a 250gallon tank, and use 22 gallons per day, divide 250 by 22 to estimate an 11day fuel supply from your tank.
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Writer Bio
Herb Kirchhoff has more than three decades of handson experience as an avid garden hobbyist and home handyman. Since retiring from the news business in 2008, Kirchhoff takes care of a 12acre rural Michigan lakefront property and applies his experience to his vegetable and flower gardens and home repair and renovation projects.