How to Calculate a Home's BTU Loss Per Hour Per Degree

All homes, whether they are apartments, houses or condominiums experience heat loss through the walls. This loss of heat can be expressed as BTU, or British thermal unit, loss. One BTU is measured as the amount of energy required to heat 1 pound of water by 1 degree Fahrenheit. You may wish to calculate your home's BTU loss per hour, per degree, to provide an estimate of how much energy you are losing through the structure of your home.

Instructions

- 1
  Determine the R-value for the walls in your home. The R-value refers to the thermal resistance of the insulation materials used in the construction of your home and is often labeled on the insulation material itself. If you do not have access to the insulation material in your walls, you will have to contact your home's manufacturer to determine the insulation material used and its R-value. R-value is usually expressed in whole numbers, such as R-10 or R-15.
- 2
  Measure the square footage of all of the walls of your home. For example, perhaps the total square footage is 3,000. Multiply the square footage by the difference in temperature inside your home and outside your home. For example, if there is a 5-degree difference, multiply 3,000 by 5 degrees to get 15,000.
- 3
  Divide the product of the square footage and the temperature difference by the R-value. For example, if the R-value is 15, divide 15,000 by 15 to get 1,000. Therefore, your home will lose 1,000 BTUs of heat per hour. You can easily recalculate to determine what the BTU loss would be at different temperatures using this method.

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