In a little-noticed move last month, the U.S. Energy Department announced new standards for microwave ovens that will make them even more efficient. Already, microwaves are a great option for saving energy when cooking (some foods, anyway), especially in summer, when turning on an oven can heat up the whole house, but a microwave focuses its heating on the food inside it.

The key to the energy savings to come, as with so many of our electronic devices: Killing the so-called “vampire load” from standby power that keeps electronics in a perpetual “on” state, even when they seem to be “off.”

It’s estimated that a typical microwave is on for 70 hours a year, but draws power for more than 100 times as long, to keep the clock and electronic controls powered. The new standards will cut the allowable energy demanded by standby power by three-fourths, to 1 watt.

This energy savings won’t add up to much in the pocket of the typical American homeowner, but over 30 years, we’ll collectively save a whopping $3.4 billion, and save enough energy to power 6 million U.S. homes. Just think of all the hot pockets that could buy! (No, please don’t.)

Since the Department of Energy began addressing standby power in 2007, according to the American Council for an Energy Efficient Economy, microwaves are the six other products, including clothes washers and dryers, dishwashers, room air conditioners, central air conditioners, and furnaces. Next up? Battery chargers for cordless equipment like drills and toothbrushes.

And a good thing, too. A new analysis by the American Council for an Energy-Efficient Economy found that so-called “miscellaneous” electronic devices — other than refrigerators, lights, or heating and cooling equipment — account for so much energy use that collectively, our use of them in homes and businesses equals the entire energy demand of nations as big as Mexico, Australia or hundreds of other countries. We use up more energy running things like computer monitors than we import, in oil, from the Middle East. The good news is that we’re so wasteful that there are plenty of low-hanging fruit: That is, we can cut energy demand significantly through initiatives like reducing standby power in microwave ovens, without noticing a bit of difference in our profligate lifestyles–a fact President Obama recognized in his recent climate speech, when he signaled out energy efficient devices as one key strategy for reducing greenhouse gas emissions.