Details for Specifying Cooking Appliances

Since the ENERGY STAR® program does not apply currently to cooking appliances, there are several things to keep in mind when specifying or selecting cooking appliances.

Energy Source. Be aware that many people prefer gas-fueled cooking appliances because they offer a greater level of control than electric ones, particularly with cooktop and stovetop burners. Since all-new gas ranges are required to have electric ignition, there is no longer the concern about wasting a continuous stream of energy from pilot lights. The potential downside to gas cooking appliances is the indoor air quality effects of gas combustion products. Specifying a ventilation fan that vents directly to the outside (not re-circulating) becomes a significant component of gas cooking appliances. Choosing a conventional updraft hood or a downdraft hood can make a difference in the amount of make-up air that has to be heated or cooled to offset the exhausted air; downdraft hoods generally require several times more air than conventional updraft hoods.

Ovens. When specifying ovens, there are many alternatives to traditional electric and gas ovens, including convection ovens, microwave ovens, and combination models. Consider the following points:

• Conventional Ovens. With standard gas or electric ovens, self-cleaning models are more energy efficient because they have more insulation. Using the self-cleaning feature more than about once a month will use more energy than is saved from the extra insulation.
• Convection Ovens. These ovens can be more energy efficient than standard ovens because the heated air is continuously circulated around the food being cooked. Heat is distributed more evenly, and cooking time can be decreased. On average, convection ovens can reduce energy use by 20 percent, compared to conventional ovens.
• Microwave Ovens. Microwaves generally use one-half to two-thirds as much electricity as a conventional electric range or oven, particularly when used for reheating small portions. Because less heat is generated in the kitchen, residual savings may accrue from reduced air conditioning during the summer months.

Cooktops and Rangetops. When considering electric cooktops and rangetops, the not-for-profit American Council for an Energy-Efficient Economy (ACEEE) suggests the following:

• Solid disk elements are more attractive than coils and they are easier to clean up, but they heat up even more slowly than electric coils. Because solid disk elements take longer to heat up and higher-wattage elements are generally used, energy consumption will be higher. Good contact between the pan and the burner is especially important with solid disk elements.
• Radiant elements under ceramic glass are easy to clean and heat up faster than solid disk elements, though not as quickly as conventional coil elements. The energy efficiency of ceramic glass cooktops is higher than coil or disk element cooktops. As with solid disk elements, flat pans are important.
• Halogen elements use halogen lamps as the heat source under a glass surface. The lamp delivers instant heat and responds very quickly to temperature-setting changes. The heating efficiency of halogen units may not be better than with ceramic glass units, and halogen elements will provide only marginally faster speed.
• Induction elements are the newest and most innovative types of cooktops. The induction elements transfer electromagnetic energy directly to the pan, where heat is needed. As a result, they are very energy efficient, using less than half as much energy as standard electric coil elements. However, they work only with ferrous metal cookware (cast iron, stainless steel, and enameled iron). When the pan is removed, there is almost no lingering heat on the cooktop. Currently, induction elements are available only with the highest-priced cooktops. The extra cost is difficult to justify on the basis of energy savings alone.

Finding ways to reduce energy use and minimize the impact on the environment are among the goals of all green building efforts, including emerging residential green buildings. Paying attention to the specifications for residential appliances that require either energy or water to operate can contribute significantly to meeting those goals.