After heating or cooling, water heating is typically the largest energy user in the home. As homes have become more energy efficient over the past 20 years, the percentage of energy used for water heating has steadily increased. In the two decades since the first federal standards took effect, water heater efficiency has steadily increased. As important, industry is bringing out new technologies that promise much greater efficiency: heat pump electric, and “tankless” and “hybrid” gas in both condensing and non-condensing formats. This section looks at the high-efficiency water heaters available and how you can reduce water heating costs with your present water heater. It is important to learn more about water heating so that you can make a good choice among competing technologies and approaches.