day must be obtained. The two figures are then averaged, and the number of units this average is below is the number of degree days for that day. For example, if for Tuesday, 3 November, the high temperature is and the low is , the average is found by adding 70 and 54, which equals 124, and then dividing by 2. The resultant figure is 62, and by subtracting 62 from 65, it is determined that there were three Fahrenheit degree days that day. The K factor is the number of degree days in any given period divided by the number of gallons of fuel oil used in a given period. Multiplying K degree-days per gallon by the number of gallons of usable fuel remaining in a tank gives the number of degree-days before a delivery is needed. See also Central oil storage Oil burner Fuel price risk management Hazardous material Heating, ventilation and air-conditioning (HVAC) United States: New England Fuel Institute Northeast Home Heating Oil Reserve Footnotes Oils Petroleum products Residential heating