Analysis of the residential heating systems based on retrofitting common gas water heater

According to the fact that now gas water heater are mostly used to provide hot water at home,points out a scheme that takes gas water heater as a heat source of hot air heating system or hydronic heating system. Presents water heater and air handler system which be used in foreign countries. Analyzes the possibility of retrofitting gas water heater into small heating system and introduces the new way to settle the residential heating question.