Yes, the size of your home does make a difference when building a green home or a green project and want to be certified. There are many factors play into the square footage and design of your home. Also with the down turn in the economy I think smaller homes will be the new norm.
- The amount of materials used in the construction of a home makes a difference in the point system. The idea is to minimize the amount of materials to construct the walls of the home. Expanding the on center spacing for studs in walls, using single top plates with interior walls and expanding the on center spacing for floor joist are just a few of the items that can help. But remember that it is important to follow current building codes and manufacturer specs.
- The size of the home will also affect the HVAC system. Running more duct runs lowers the efficiency of the system resulting in more energy to heat and cool a home.
- Designing the home to minimize what is called wet walls. These are walls that have plumbing in them. Design the home so bathrooms and the kitchen are as close as possible. This saves on material to run water lines and drain lines.
The National Association of Home Builders Green Program has done extensive research to determine what the appropriate square footage based on amount of bedrooms should be. In the NAHB Green Program they have devised a chart which helps with determining the proper square footage. They have also assigned a point system to encourage new home construction to minimize the size of green homes. The chart below explains how the point system works.
Guidelines for Efficient Floor Plan Design
# of Bedrooms
Sq Ft —  2  –/–  3  –/– 4 –/–  5 –/- Points
Sq Ft — 1382 - 1890 - 2648 - 3424 - 0
Sq Ft — 1332 - 1825 - 2555 - 3296 - 1
Sq Ft — 1282 - 1756 - 2459 - 3172 - 2
Sq Ft — 1232 -1688 - 2363 - 3048 - 3
Sq Ft — 1182 - 1619 - 2267 - 2925 - 4
Sq Ft – 1132 - 1551 - 2171 - 2801 - 5
Sq Ft – 1082 - 1482 - 2075 - 2677 - 6
Sq Ft — 1032 - 1414 - 1979 - 2553 - 7
Sq Ft — 982 - 1345 - 1883 - 2430 - 8
Sq Ft — 932 - 1277 - 1788 - 2306 - 9
The LEED certification also has points based on the size of the home. It is not described as well as the NAHB Green Program. If you use the actual work sheet it takes into count the square footage of the home but does not provide an easy read chart like above.
So yes the size of the project does matter. So if you are planning on building a new home and want to Go Green, you need to start in the designing phase before you begin the project.
