The dishwasher is often one of the biggest signs of "making it" in life: it's not necessary but it's such a convenient luxury to have, especially once you have a growing family. It's also one of the more complicated choices for consumers looking to reduce their energy use because it burns resources in different ways – electricity to operate, water to clean, more electricity to heat the water and yet more for drying.

Surprisingly, most modern dishwashers are as efficient – if not more so – than hand-washing your dirty crockery, so you needn't feel so guilty about buying one any more!

The CEE calculates dishwasher efficiency in two ways: by power usage (the usual kWh per year) and by giving each model an "Energy Factor" (EF), which measures the number of cycles the appliance can run with 1kWh of electricity.

The practical result of their rating system is a list of models which use less than 295 kWh/year (17% less than the federal minimum) and 4.25 gallons of water per cycle. The list can be found on their site .

Buying Tips

When you're looking for a dishwasher, bear in mind these three rules:

1. Pick a model that has a no-heat drying option. These appliances circulate room-temperature air through instead of wasting power on a heating element.
2. Pick a model with the lowest water usage. Less water means less power use and smaller water bills, too!
3. Pick a model with lots of different wash cycles. And if you only ever use the automatic option, choose a machine that's clever enough to figure out what to do by sensing how much muck there is on your dishes.

Usage Tips

Dishwasher energy use is also significantly affected by how you use the appliance. Unlike some simpler machines, there is a variety of rules to bear in mind with these:

• Be neat: dishwashers are designed to optimize water flow through your dirty dishes. There's a reason the trays have specific uses and the manual shows you how to load the machine "properly" – if you don't, you're wasting power and water.
• Fill it up: while it's important to put everything in the right place, it's also vital to make sure the machine is full before operating. Dishwashers use the same amount of water when they're full as they would to wash a single spoon.
• Don't pre-wash: most modern dishwashers (pretty much any post-2000 model) do as good a job for dried-on cooking pots as for almost-clean dishes. If you really must meddle, a quick scrape and a cold-water rinse by hand is sufficient.
• Choose the right cycle: always opt for the lowest-energy cycle to do the job. You can also turn down your home's water heater, since most modern dishwashers have built-in heaters to provide any boost they may need.