while the user's arms reach over the top. Efficiency The 2014 ACEEE Summer Study on Energy Efficiency in Buildings concluded that "induction cooking is not always the most efficient method of cooking. When tested with a large cooking vessel, the efficiency of conventional electric technology was measured to be higher (83%) than that of induction cooking (77%). Yet the efficiency of conventional cooking appliances was shown to be highly dependent on the size of the cooking vessel." Cooking methods that use flames or hot heating elements have a significantly higher loss to the ambient environment; induction heating directly heats the pot. Because the induction effect does not directly heat the air around the vessel, induction cooking results in further energy efficiencies. Cooling air is blown through the electronics beneath the surface but it is only slightly warm. The purpose of a cooktop is to prepare food; for example, long periods of simmering may be required. Published energy efficiency measurements concentrate on the ability of a cooktop to transfer energy to a metal test block, which is easier to repeatably measure. Energy transfer efficiency, as defined by U.S. Department of Energy (DOE), is the percentage of the energy consumed by a cooker that, at the end of a simulated cooking cycle has been transferred as heat to a standardized aluminum test block. The DOE test cycle starts with both the block and the cooktop at 77 °F ± 9 °F (25 °C ± 5 °C). The cooktop is then switched to maximum heating power. When the test block temperature reaches 144 °F (80 °C) above the initial room temperature, the cooktop power is immediately reduced to 25% ± 5% of its maximum power. After 15 minutes of operation at this lower power setting, the cooktop is turned off and the heat energy in the test block is measured. Efficiency is given by the ratio between energy in the block and input (electric) energy. Such a test, using two power levels, is intended to mimic real life use. Wasted energy terms such as residual unused heat (retained by solid hot-plates, ceramic or coil at the end of the test), and losses from convection and radiation by hot surfaces (including the ones of the block itself) are disregarded. In typical cooking, the energy delivered by the cooker is only partly used to heat the food; once that has occurred, all the subsequent energy