The purpose of this investigation was to identify and quantify the inefficiencies of installedresidential gas furnace systems. The systematic measurement of each possible source of inefficiencyoutlines the probable range of efficiency of existing installations, defines the"attainable" efficiency of a good installation, and points out the modifications required toachieve the attainable efficiency.

This report describes the results of the individual testing the analytical syntheses ofseasonal efficiencies, and the recommendations for standards for existing and new installations.