Designated as an American National Standard, the Uniform Solar, Hydronics and Geothermal Code (USHGC) is a model code developed by the International Association of Plumbing and Mechanical Officials (IAPMO) to govern the installation and inspection of solar energy, hydronic heating/cooling systems, and geothermal energy systems as a means of promoting the public's health, safety and welfare.
This process brings together volunteers representing a variety of viewpoints and interests to achieve consensus on solar energy, hydronic heating/cooling systems, and geothermal energy practices.
Recognizing the necessity for a solar energy code to be adopted by jurisdictions as a means of regulating such systems, IAPMO passed a resolution at its 1975 annual business conference to form a technical committee for the development of such a document.
After several months of work, this committee, composed of individuals representing industry, public utility companies, inspectors, plumbers, and engineers, completed the Uniform Solar Energy Code's (USEC) first edition and in September 1976 this document was adopted by IAPMO.
In December 2011, the Radiant Professionals Alliance joined IAPMO and soon after work began to incorporate hydronic heating/cooling provisions into the USEC to be released in 2015 as the Uniform Solar Energy and Hydronics Code (USEHC).