Earth Talk: The most energy-efficient way to heat a cup of water
When choosing among the microwave or a gas or electric stove top, the answer may surprise you.
Joanne Ciccarello/Staff/The Christian Science Monitor
Q: How does the microwave compare in energy use, say, to using a gas or electric stove burner to heat water for a cup of tea?
– Tempie, Dexter, Mich.
A: The short answer is that it depends upon several variables, including the price of electricity versus gas and the relative efficiency of the appliances involved. Typically, though, a microwave would be slightly more efficient at heating water than the flame on a gas stove and should use up a little less energy. The reason: The microwave’s heat waves are focused on the liquid (or food), not on heating the air or container around it.
Given this logic, it’s hard to believe that an electric stove top would be any better, but an analysis by Home Energy Magazine found otherwise. The magazine’s researchers discovered that an electric burner uses about 25 percent less electricity than a microwave to boil a cup of water.
That said, the difference in energy saved by using one method over another is negligible: Choosing the most efficient process might save a heavy tea drinker a dollar or so a year. “You’d save more energy over the year by replacing one light bulb with a CFL [compact fluorescent light bulb] or turning off the air conditioner for an hour ... at some point over the whole year,” says Michael Bluejay, author of a website about saving electricity.