The roving finger of home energy blame finds another target in today’s New York Times. The microwave oven is portrayed as the biggest guzzler of home energy in a confusing table of bar charts and percentages.
It’s true that newer technologies with always-on or standby functions are increasing the demand for home electricity, but we must remember that these aren’t all simply adding to the demand — sometimes they’re replacing it. The microwave is a perfect example.
For small meals, the microwave is by far and away the most efficient (and by extension eco-friendliest, and cheapest) way of cooking. In fact, the same meal can consume less than 1/5th (pdf) the amount of electricty if cooked in a microwave rather than a conventional convection oven.
So why the confusion? Well, it’s true that the microwave does have a very high energy consumption rate of around 800 watts. But nobody has the microwave oven on all day. This is where the numbers can get misleading — power ratings (generally given in watts) must be multiplied by the time the device is actually in use to make for simple comparisons. A little bit of math reveals that the microwave’s quick heating ability results in a net gain in efficiency over conventional stoves (if not necessarily a gain in good flavor).