The Home Energy Rating System (HERS) is a system designed by the US Department of Energy using highly specialized software to model the Energy Efficiency of a home. The more efficient the home, the lower it’s number on the HERS Index. A true Zero-Energy Home would rate Zero. The average existing home today rates about 130, and today’s code minimum home rates about 100. All of our homes rate less than 55, (without PV, or other power generating equipment) which means that they will each use less than 55% of the energy of a code-built home.
The HERS rating system uses a very sophisticated software program called Rem-Rate. This program analyzes the insulation levels in each of the walls, floor, and roof. It takes into account the energy efficiency of the windows and doors, how well the home is air-sealed, and finally what heating and cooling equipment, appliances, and lighting systems are used in the home. The program can then determine how much energy will be required to supply the home under average use per year. Energy production equipment is then taken into consideration, such as solar photo voltaic panels, or wind generators, to come up with the final number for the house.
It is our goal to take the HERS number far enough below zero that the home can produce enough energy to offset the energy used to build, and then finally to recycle the home at the end of it’s life-cycle. If we can also power the transportation systems used by the occupants, we will have really accomplished something really important! To date, about a dozen of our plans have proven to generate enough surplus energy to power the owners car! In September, 2012 we trade-marked the name “Positive NRG™ Home” to identify the home plans that can achieve this lofty goal.