Introduction There are various technologies for heating a residential home. Those choices include natural gas, propane, electricity and wood. Operating costs for heating a home tend to vary from year to year as fuels are market driven. Resources become less accessible every year. Today there is great interest in energy efficiency, conservation and protection of our environment. The development of new energy sources is important and such examples include solar, wind and geothermal energy. However, by using more efficient and economical storage devices we can use our existing resources more sensibly. Fortunately, more advanced options are available today that use closed-loop control systems. A closed-loop control system is defined as “measuring the difference between the actual value of the controlled variable and the desired variable and using the difference to drive the actual value toward the desired value.” An example of a closed-loop control system is electric thermal storage (ETS). What is Electric Thermal Storage (ETS)? Electric thermal storage (ETS) heat is a quiet, odorless, and economical technology that uses electricity. The ETS concerns the development of the transformation of electricity into thermal energy and its saving in the form of heat. The ETS has been around for decades and is commonly used in Europe and Canada. However, this type of storage is not feasible in areas where electric service is lacking or electricity is at high prices. The ETS is effective where peak-hour energy capacity is offered at low prices. Heat can be stored in some types of storage materials. The most common type of storage material is high-density ceramic bricks with an electric heating element in the center. The bricks are encased in an insulator......paper core......charged, some of the heat is released into the room to provide immediate comfort. The rest of the heat is stored in the bricks until it is used. During peak hours, the heating elements are turned off. The insulation around the core helps the bricks retain stored heat. After the ETS unit is charged, fans inside the heater move air around the bricks. The air is heated to 180-200 degrees and returned to the room. Since the process is controlled by a wall thermostat, you can achieve the desired amount of heat. Ceramic bricks are made of a high-density iron oxide that surrounds the elements to absorb heat. The high-density compound accomplishes two things. First, it retains more heat for a longer period of time, and second, it requires less space. See Figure 1 for a pictorial representation of an electric thermal storage unit.4