For the purposes

For the purposes of this Strategy Guideline, an energy efficient house is defined as one that is
designed and built for decreased energy use and improved comfort through higher levels of
insulation, more energy efficient windows, high efficiency space conditioning and water heating
equipment, energy efficient lighting and appliances, reduced air infiltration, and controlled
mechanical ventilation. Specification levels for energy efficient houses have historically been
prescribed by beyond code programs that set a percentage better than code for energy use, such
as ENERGY STAR®, which requires houses to be 15% more energy efficient than code. Beyond
code programs continue to set a percentage better than the improved codes for energy use,
raising the bar for whole house energy efficiency. The 2009 International Energy Conservation
Code (IECC) establishes an estimated 15% improvement in energy efficiency over the previous
2006 IECC requirements. Ongoing code cycles incrementally increase the minimum efficiency
of a house. For example, the 2012 IECC achieves approximately 30% savings over the 2006
version. As the new codes are adopted and implemented, a house that was built under an above
code program in 2010 will likely be the code mandated house in 2015. As the energy efficiency