There is a big difference between Total Living square feet and Total square feet. While they both refer to the size of a house, they are not the same thing. If you mix them up you can be in for shock when it comes time to get an estimate or when you move into your new home.
When house plan sellers refer to Total Living square feet, they are referring to the “living area” of the home. This can be thought of as the area that will be heated or cooled. It is called the living area because this is where you spend your time.
An attic, while a useful storage area, is not living space. Same with the garage or basement space that is not finished. Even some spaces over a garage are not considered “Living Area”. It depends on the home designer and the specific home plan.
Total square feet is just that. The total foot print the home will take up. This area includes garages, porches, patios, and any area under the main roof. This sometimes will include detached structures like detached garages, guest suites, or cabanas.
You use the Total Living square feet when you are considering what it will be like to live in the house. It can also be used to calculate the square feet needed depending on the number of people in the home.
Generally, the number of people that will be in the house should be multiplied by 550 sq. ft. For example a family of 4 should be looking at homes no smaller than 2200 sq. ft. Of course this is just a rough guide, but it can be a helpful tool.
The Total Square Feet is arguably more important. This number will be used by your builder to help calculate the estimated building cost. In some cases it might also be used to see if a house plan meets the requirements of local building codes or guide-lines.
If you give a builder the Living square feet number to use in his estimate calculations, the costs will be all wrong. So it is very important that these two numbers are clearly understood. The only other numbers that come close to being this important are the width & depth of the plan. But that is an article for another time.