Microwave Cooking May be Most Efficient, EPRI Says

The Electric Power Research Institute compared the energy use of frozen food cooking in microwaves, toaster ovens, and conventional ovens.

Consumers who are looking for ways to save time during the holiday season also may have an opportunity to save energy when preparing pre-packaged meals. Two things are key: be flexible in choosing your dishes, and when possible use the microwave or toaster oven instead of the conventional oven, according to research from the Electric Power Research Institute (EPRI).

Americans increasingly rely on frozen or prepared meals instead of cooking from scratch – primarily to save time. Grocery stores cater to these hurried cooks with a growing variety of frozen breakfast, lunch and dinner options, including pasta dishes, burritos and other Mexican dishes, pizzas, and even variations on what used to be called “TV dinners.”

According to MarketResearch.com, 72 percent of Americans buy frozen foods, and two-thirds of households purchase frozen pizza. For most frozen entrees, pizzas and meals cooks have the option of using a microwave, toaster oven or conventional oven.

EPRI assessed the energy required for these cooking options at its Energy Efficiency laboratory in Knoxville, Tenn., and found significant differences. If you eat pre-packaged meals, a microwave would be the most efficient way to cook it (see chart below).

For cooks in a hurry, the time savings can add up. For example, cooking a frozen submarine sandwich that required 2 minutes 45 seconds in a microwave required 23 minutes in a toaster oven or conventional oven.

Individually differences in energy savings are small, but the true extent of the power consumed is impressive when calculated nationally. For example, if the 34 million American households estimated to regularly consume single serving frozen pizzas cooked two of them per week in a microwave instead of an oven it would save 1.5 billion kilowatt hours of electric energy per year, or enough to power New York City’s 3.2 million residential electricity customers for one month. Alternatively, by switching from conventional electric ovens to toaster ovens, approximately 680 million kWh of electric energy could be saved a year.

Energy Use in Watt Hours

Microwave oven Toaster oven Conventional oven

Single Serve French bread pizza


308 504

Lasagna dinner

253 N.A 716

Chicken Parmigiana dinner

151     N/A 537

Lemon Pepper Fish dinner

102 N/A 513

Breakfast Burritos

54         320 N/A

Toasted Submarine Sandwich

75 297             486

Note: For the food tested, the “not applicable” (N/A) resulted because cooking option was not included as part of the cooking instructions.


EPRI also recently published a reference card (pdf) to help communicate the tradeoffs associated with various electricity generation technologies. The tool compares technologies such as renewables, coal, natural gas, and nuclear in terms of their relative benefit or impact in a number of areas.

Factors evaluated include the cost to build a power plant, the amount of land required to support the plant’s operation, the plant’s water requirements, air emissions and waste products, and the ability of the technology to generate electricity when needed.

The reference card uses simple graphics to convey the scale of electricity generation options, the mix of generation technologies in use, and the amount of time a given generation technology typically operates. Using the city of Chicago as an example, the reference card illustrates how many power plants of each type would be required to meet the electricity demand of one million households.

“This reference card should help sort out some of the complexities with electricity generation and the range of factors that must be considered in making decisions about new generation technologies,” said Michael Howard, EPRI president and CEO. “The purpose of this effort is to provide all interested audiences with a beginning framework for understanding the scale, economics, environmental impacts, and reliability of power generation options.”