We all love our microwave ovens. Cooking in the days before microwaves (pr
e 1980's) involved a lot of patience and saucepan scrubbing. We ate a LOT more cold lunches then. Microwaves took over quickly as a convenience time-saving device and were taunted as more energy efficient as a second reason to buy them. But how much money do they actually save?
Enter Mr. Electricity (Michael Bluejay) who has done an excellent job of quantifying the energy use and cost of cooking things at this site: Saving Electricity
His math shows that cooking something in the oven vs 15 minutes in the microwave (2 x baked potatoes comes to mind here) saves a LOT at $0.24 vs $0.04 but that you could also cook the same thing in a toaster oven and it would equal the cost of the microwave. Note that gas ovens still use electricity and that convection ovens use 2/3 as much electricity as regular ranges.Let's say we want to compare heating a cup of water in a saucepan to microwaving it, to make some tea. Referring to the power consumption table at: ABS Alaskan
a hot plate consumes 1200W and a high power microwave 1500W (with 1100W cooking power). It takes 2 minutes to superheat a cup of water in the microwave. To get a saucepan with one cup of water to a full boil takes 5 minutes. The microwave takes 0.05 KWh and the stove takes 0.10 KWh, exactly twice as much energy. I suspect that to boil a dutchoven full of water would not be practical in a microwave which is how I make ice tea here, several pitchers at a time. In the old days it took 40 minutes to cook a "tv dinner" in the oven (plus 10 minutes to preheat the oven to 350 degrees). The modern microwave version takes about 6 minutes. So using 2000W for oven power the tv dinner takes 1.67 KWh and the microwave takes 0.15 KWh to do the same job, less than a tenth as much! It would take about 200 "tv dinners" to pay off a cheap $40 microwave oven in electricity savings. Clearly the oven and burner come closer on big jobs (like roasts, turkeys, large casseroles) or may be the only practical solution. However the microwave clearly has a home for quick warmup of leftovers or reheating that coffee or making one cup of tea. I always suspected the toaster oven is a good interim solution but mostly we use ours as a 4-slice toaster.
