Refrigerators and freezers just keep getting cheaper to run.

In September, new energy-efficiency standards for refrigerators and freezers will take effect, along with more rigorous energy testing of the appliances. Already, refrigerators that meet the new standards are hitting the market.

As a result, most full-size refrigerators will be 25 percent more efficient than appliances manufactured 10 years ago. And those models already had made great strides, using 40 percent less energy than conventional models sold as recently as 2001.

Newly redesigned Energy Guide labels – the bright yellow labels attached to new appliances – will help you compare energy use when you shop. The labels on the new refrigerators will have yellow numbers on a black background, which tells you those models were tested using the new procedures, so the results are more reliable than they used to be.

Wonder how your refrigerator stacks up? Energy Star has a Refrigerator Retirement Savings Calculator that tells you how much you’d save by replacing your current fridge with a more recent model.