Microwave could save electricity, depending on food quantity

Q. I plan to use my microwave oven more instead of the range/oven to save electricity. I gave my old microwave to my mother and I need a new one. What should I look for in a new one that I plan to use often?

A. You are correct that a microwave oven uses less electricity than a range top cooking element or an oven for most food items. Keep in mind though, if you are cooking large quantities, using a regular oven may be more efficient. This is particularly true when cooking several items consecutively because the regular oven's thermal mass retains the heat.

A typical electric heating element in a regular oven is 4,000 watts or more. A large microwave oven may use only 1,400 watts on high and it cooks faster. Even though the heating element in a regular oven switches on and off once it is preheated, the microwave oven still uses less electricity.

If you are a numbers junkie and what to crunch the numbers to determine when to use either oven, check the product label on the back of the microwave oven for its total wattage used. Microwave ovens are often rated by their heat output in watts. A 900-watt-output microwave oven might actually use a total of 1,400 watts of electricity for the light, fan, rotating dish, and controls.

Microwave ovens have evolved since your previous one. The basic heating technology is similar, but the controls are much better. Since you are planning to do as much cooking as possible, select a model with a sensor control. This sensor, typically a moisture sensor, determines when the food type, which you select by pushing a button, is properly cooked. Combination models with convection heating, halogen browning lights, etc., are also available.

There are many more preprogrammed cooking settings on newer microwave ovens and they seem to work very well if you follow the quantity guidelines. The next generation controls, which several models now offer, match a preprogrammed setting with cooking codes from the food manufacturers. If you are cooking a food mix, just input the microwave cooking code listed on the box.

For even cooking, most modern microwave ovens use a rotating turntable. This is effective for most cooking, but there may not be enough interior clearance for a large rectangular casserole to rotate. If you like to cook large casseroles to have food done in advance, select a model with an oscillating sliding tray to provide even cooking.

OTR (over-the-range) microwave ovens are convenient to use and save space, but they typically cost considerably more than countertop models. Whirlpool recently introduced a new OTR model with a built-in range hood that vents outdoors similar to a typical range hood.

Q. I have done a remodeling project at my house and I have some fiberglass batt insulation left over. When I finish the interior wall, does it make energy sense to put insulation inside these walls, too?

A. Putting insulation in interior walls between rooms will not save energy. The only way it may save a little is if you zone heat your house and the temperatures in adjacent rooms are significantly different.

Generally the only reason for putting insulation inside interior walls is to block sound transmission between the rooms. If this important to you, in addition to the insulation, add a second layer of drywall and caulk any gaps.

• Write to James Dulley at 6906 Royalgreen Drive, Cincinnati, OH 45244, or visit dulley.com.