: Introduced more stringent equipment efficiencies and specific design requirements for hydronics and airside systems. It also mandated variable speed pump control for many chilled water systems.
: Updated Lighting Power Density (LPD) allowances and introduced more detailed methods for determining power allowances, such as the Space-by-Space Method. ashrae 90.1-2010
This 2010 version was a major leap forward, achieving nearly compared to the 2004 edition and roughly an 18.2% reduction in source energy consumption over the 2007 version. Key improvements included: ashrae 90.1-2010