HVAC sizing tool is free to use room by room load calculation tool. It is based on residential heating and cooling design methods developed by the Air Conditioning Contractors of America (ACCA). This tool is only intended for HVAC contractors and others who are familiar with HVAC design principles and basic building science. The Help Menu contains a link to a YouTube channel with basic tutorial presentations. The only support of the tool is through the help menu and context sensitive pop-up help windows.

Results from use of HVAC and any values, estimates and recommendations included herein are only intended to assist the recipient in evaluating design options and should not be used in lieu of professional engineering services. Moreover, the report and its contents are provided "as is" without any warranty or representation regarding quality, accuracy, non-infringement, or usefulness. The HVAC Sizing Tool uses HVAC industry standard heat gain and heat loss calculations, with simplified sets of typical construction material properties. This product is not ACCA certified, but has been verified for calculational accuracy.