BEST is an early project phase HVAC system comparison tool including over 100 industry-defined defaults so that anyone on the design team can see the key assumptions. The goal is to inform the user about complete HVAC system performance in comparison to other system choices for the same building to assist in making informed decisions about HVAC system type.

This free tool has many adjustable inputs, which building owners, designers, and contractors can use to model any building in any location. Simply enter the square footage, number of stories, the nearest city for local weather data, and choose up to four HVAC systems – from more than 30 pre-loaded systems to compare. The tool uses AHRI-certified performance data and new BEER to model the HVAC system as it will operate in real life – not the test lab.