Conditioned floor area includes the rooms inside your home that are heated and/or cooled. This will generally include the main living space, and could include a finished basement area. It should not include a garage, attic, unfinished basement or storage space. To determine your home's conditioned floor area, you may need to do some simple measurements.
If your home is rectangular in shape, measure the outside dimensions (length and width). The simplest way is to measure off the length of your pace and then walk along the outside walls. Take a normal step next to a yardstick or tape measure to determine the length of your pace. When you walk along the house, count the number of paces then multiply that by the length of your pace. After you have the outside dimensions, multiply that by the number of floors that are heated and/or cooled.
If your home is not a simple rectangle (for example, if it is L-shaped), you can sketch a floor plan and divide it into rectangles, measure the outside dimensions of the individual rectangles, then add up the area of each rectangle.