Does Having Two Dishwashers Make Sense?

The use of automatic dishwashers has long been controversial on Treehugger. The consensus has always been that dishwashers are actually more energy and water-efficient than washing by hand; Larry West wrote:

"Scientists at the University of Bonn in Germany who studied the issue found that the dishwasher uses only half the energy, one-sixth of the water, and less soap than hand-washing an identical set of dirty dishes. Even the most sparing and careful washers could not beat the modern dishwasher. The study also found that dishwashers excelled in cleanliness over hand washing."

But unloading dishwashers can be a pain. I recently got into an interesting debate after seeing a tweet from author and editor Allison Arieff:

I responded by noting something I proposed for a client many years ago: Install two dishwashers. Keep all your regular dishes in one of them; when they are dirty, put them in the other, and when it is full, wash them and reverse the process. I pointed out that you wouldn't even lose cupboard space because one dishwasher was always essentially acting as storage.

Some people, including architectural critics, thought this was a good idea; British architectural critic Will Jennings pointed out that environmentalists should be concerned with the embodied carbon of making the dishwasher, and he has a good point; the average 24" wide North American dishwasher is a hundred pounds of metal and plastic.

However, you could do this with two euro-sized 18-inch wide dishwashers or a two-drawer Fisher-Paykell dishwasher and reduce the amount of steel, and space, by a little bit. I looked around a little to see if anyone else had proposed this and found that in fact, it is common in high-end kitchens, where often the second dishwasher is cheaper than the fancy cabinetry.

The subject is discussed on Reddit, where of course duplicating dishwashers is called a RAID-5 Dishwasher setup. (RAID is short for "Redundant Array of Independent Disks" and is a way of sharing data among hard drives. RAID-5 means "distributed parity.") The Redittor asking the question wondered, "is this a 'what were they thinking?' idea?"

 "With three pretty young kids (range 4-8) and two working parents, things are never perfect, and our kitchen is a mess most of the time. We prefer to enjoy our lives to seeking perfection in the kitchen... But there's the idea. With two dishwashers, there will be no unloading part. One dishwasher is like a shelf – storing clean dishes. And the other is like a sink for dirty dishes. When the latter gets full, turn it on, and swap the roles. Rinse and repeat, literally."

There were 361 responses. Most of them are from people complaining that the author should raise his kids properly and have them do it. "Put the kids to work on the dishes. The 8-year-old is certainly old enough for that." But "Many Redditors suggested a Fisher & Paykel dishwasher which has two independent drawers. Some Redditors have it and love it."

While we can make a sustainability case for one dishwasher, I certainly cannot make a case for two because of the embodied energy involved in building the dishwasher. Katherine Martinko in the frugal green living department would probably say it is a waste of money. But from a design and convenience point of view, it makes sense to me.

I can't embed a poll here, but click here to go to the poll and tell me what you think: Does having two dishwashers make sense?