Water heaters that work off demand as well as storage provide the best of both worlds in the area of hot water heating. Depending upon the amount of hot water needed at one time, either a direct heating appliance or an appliance with direct heating and storage will be the best solution. Many times with new home construction that is very tight, the amount of energy (BTU's) required to heat domestic hot wateris much greater than the amount of energy required to heat the space. The newer appliances that use step fire technology, can regulate how much energy is delivered based on these changing conditions. One appliance has many ranges of application.