Learn about a tool that you can use in the early design phase – before there is even a building – to compare HVAC systems and allocate construction dollars to HVAC systems. The Building energy efficiency rating is examined for real world vs. AHRI published IEER data comparisons for VRP and ground source heat pump systems and alternative ratings are discussed. We then introduce a Building Efficiency System Tool (BEST) that allows users to evaluating potential HVAC system choices for a new project and compare complete HVAC system choices for efficiency against costs, which are based on their building, in their city, and meet their requirements.