Unless you're a hand-wash wizard with an unheard-of ability to stretch minute amounts of water over entire bridal registries of glasses and plates, washing dishes in the sink uses much more water as an efficient dishwasher. And by efficient, I mean not necessarily just the high-dollar models; pretty much any new dishwasher is going to be more efficient than your hands. Which to me is good news: Who wants to stand at the sink for 20 minutes when the new fall shows are on?

After heating (and cooling) your home and lighting it, heating water is the next biggest energy eater. Your dishwasher, radiant heat (if you have it), clothes washer and shower all demand water heated to at least 120 degrees. Constantly. So, obviously, the less hot water you use, the lower your energy demands. Less demand = money saved and pollutants unreleased.

Thus, faced with a choice between a mostly useless old dishwasher and washing by hand, getting a new machine was put pretty quickly on our House Upgrade Master List. But not very high up. There was no months-long search on DishwasherTalk.com, no grilling of friends and neighbors over their shiny models. But then one sort of fell into our laps – or into my inbox, rather. A local couple had posted an ad for a brand new machine on the Boulder Green Building Guild e-newsletter. They realized after it was delivered that they had bought the wrong size, so all we had to do was drive over, pay them and pick it up – thus saving the world from all those nasty carbon emissions had they shipped it back to the retailer. (Maybe that's a stretch, but every little bit helps, people.) This easy act of greenery saved us $150 over the retail price, too.

The new one's a Whirlpool Gold GU2400XTP. It uses an average of seven gallons of water per cycle – probably half of what the old one did – and Consumer Reports gave it "Very Good" ratings for energy use. (A few models tested higher in that category, but were twice the price of the Whirlpool.) We use it all the time now: The 2400 has a shorter cycle for smaller or not-that-dirty loads, and if we need to leave dirty dishes in it until it's full, we run a rinse cycle - which, counterintuitively, uses much less water than rinsing them by hand. (Pretty stupidly, I had always thought dishwashers worked by continuously pumping water through the tub. One of those things I dreamt up as a kid and never quite really let go of. But that's not the case: a tub fills only two or three times per wash cycle, and just once per rinse.) With the 2400, full load of pre-rinsed-by-the-dishwasher dishes will get clean on the light soil setting. Less water, less demand. Rather than rinsing, though, we've been trying to remember to scrape off any lingering foodstuffs. Bit of a challenge, changing our habits from running the tap to keeping a rubber scraper near the sink, but we're progressing, dish primitives that we are.

As for old Klanky, not to worry. We made up for it: first by trying to Freecycle the old guy (no one was interested, unsurprisingly), and then by dropping him off at Boulder's Ecocycle, where he was recycled as scrap metal.

NEXT TIME: Installing dishwashers is easy... right?