Cold Water Dishwashing? An Experiment in Green Living

When you live in an old, drafty dump of a house — like, for example, mine — you learn to innovate in order to keep your energy bills from looking like the Pentagon budget.

So last night I ran my dishwasher using only cold water. Blasphemous, I know, but Ed Hagerty (one of my readers) inspired me to try something different. Like me, Ed lives in the cold Northeast and we both use an oil furnace to heat our hot water.

Ed wrote to say that he’d slashed his oil bill by switching off his oil furnace except when he knew he’d be using the shower or dishwasher. Otherwise, the unit runs every hour or so, 24/7/365, to keep a ready supply of hot water. Oil companies LOVE you for that, but it gets expensive. Trust me.

I decided to go one step further and try running my dishwasher without hot water (turning on the furnace only for showers). After all, cold water works fine for clothes washers — why not dishwashers?

The results? Surprisingly good. My dishes were as clean as usual, though I saw a few more spots on my glasses.

A little reading tells me why: most newer dishwashers are self-heating, and don’t rely on incoming hot water anyway. It’s also worth noting that hot tap water isn’t really hot enough to kill germs — the detergent does that — so there’s no reason not to wash with cold water.

Thanks, Ed!