Apparently, if your dishwasher is more than 10 years old it is worth investing in a new one. The energy cost of running such an old machine is prohibitive. One article I read mentioned possibly donating an old machine. In my opinion it would be much better to call someone who will cut it up for scrap and find uses for the motors, fans, etc. Our dishwasher is not new and it is not an Energy Star model but it is only 2 or 3 years old. My Dad gave it to us after he installed a new one only to find their was a malfunction in his plumbing, not in the dishwasher. Anyway, the front says it is a "whirlpool - Imperial Series". A word of warning, according to the TreeHuggers article the new dishwasher with dirt sensors can actually use MORE energy than those without.
How you run your dishwasher will play a big role in the amount of energy it uses. If you can, have someone adjust your hot water heater's thermostat down to 120 degrees F (also see this & join this). Here's the obvious advice: run only full loads. This has been harder then I thought with the bottom/top filling up faster than the other. So what if you have to hand wash a few plates to even things out? Try not to pre-rinse most of the dishes if you can help it. I have found that usually the dishwasher does a good job without rinsing first, just scrape off any chunks of food (preferably in to your compost bin!). If your dishwasher has a delay or timer feature, or depending on when you're home, consider running it during off-peak electricity hours. Call your utility company to check out their options and programs, don't just assume you'll be saving a lot of $$$. Another common sense tip is to avoid the heated drying cycle and allow your dishes to air dry. Open it up and dump any water that is sitting on the bottom of cups, bowls, etc. Then leave the door cracked overnight and things should dry out. Alternatively, grab your dish towel and wipe any wet surfaces as you put them away.
Okay, on to the fun part: detergent. This biggest thing to avoid is using a detergent with high levels of phosphates. These are the components used in fertilizer that cause algae to grow in unwanted places and create a lot of damage to fish & wildlife habitat. The Michigan Environmental Council put together a nice list of phosphate levels in different detergents. Check the side of the box for more accurate levels. The partial box of Cascade PureRinse powder that my boss gave me has this lovely statement on the side of the box:
6.4% !!! That's actually 2 points higher than the content listed in the aforementioned article. I found this option
here (available in gel, powder, or tablet, scented or unscented) and several options on Amazon.com
If you do have products shipped to you try to order in bulk and consider requesting limited packing materials. Most manufacturers' websites have a "find a store" feature now. There are also several recipes out there for homemade detergents. This is the route I plan to take since I'm already making my own homemade laundry detergent and it works great. The gals over at The Dollar Stretcher (which is a site I have loved for years and highly recommend!) suggest a 1/2 & 1/2 mix of borax and baking soda. If that sounds a little too simple for you, and it does to me, then look here.
It seems that phosphate-free options are more likely to cause a cloudy appearance on glass, and who doesn't love a good rinse aid anyway? You may already use white vinegar, and there are other options (see links on the bottom of that last article).
I will post more here once I figure out what works for me. I hope I've gathered together some useful information. Feedback is more than welcome! :)
*Update: I just found this great post over at One Green Generation.