Once the amount of energy lost per square foot in a year has been determined, the cost of heat loss due to energy transfer can be calculated.
1.) Determine the cost of heating oil, for example $4.00/gallon
2.) Determine the amount of energy in a gallon of heating oil (heating oil #1 contains 130,000 BTU/gallon)
3.) Calculate the cost of the energy lost through one square foot of the wall over a period of a year. This is done by multiplying the energy loss (Q) by the price of fuel per gallon ($4.00) and dividing by the amount of energy in a gallon of fuel (130,000 BTU/gallon).
The result will be in units of dollars per square foot per year. This is the estimated cost of heating one square foot of your wall for one year. To determine the total annual heating cost, the cost per unit area per year is multiplied by the total area of the outside walls. This results in the annual heating cost for the structure ($/yr).
