What major factor influences a home's HERS Index score?

The HERS Index score is primarily influenced by the home's structural design and energy systems. This includes critical elements such as insulation levels, the efficiency of heating and cooling systems, the type and efficiency of windows, and the overall layout and orientation of the home. These factors significantly dictate how much energy a home consumes and its overall energy performance.

A well-designed home with efficient energy systems will generally receive a lower HERS Index score, indicating better energy efficiency. In contrast, homes with poor insulation, outdated heating and cooling systems, or inappropriate window performance will reflect higher energy consumption and consequently a higher HERS Index score. Therefore, the assessment of these structural and mechanical components is fundamental in determining a home's energy efficiency and ultimately its HERS Index score.