Automatic dishwashers are really cheap per hour saved. The actual costs will vary widely (esp. in the US, where the cost of electricity is much lower than where I live), but our best estimate at the time of buying was $2/hour saved (based on halving the 30 minutes we need to do the dishes, and assuming it breaks the moment it’s out of warranty—not entirely unreasonable, since we pretty much bought the cheapest option.) Locally, about half is depreciation of the dishwasher and half is electricity/washing powder/water (negligible).
Automatic dishwashers are really cheap per hour saved. The actual costs will vary widely (esp. in the US, where the cost of electricity is much lower than where I live), but our best estimate at the time of buying was $2/hour saved (based on halving the 30 minutes we need to do the dishes, and assuming it breaks the moment it’s out of warranty—not entirely unreasonable, since we pretty much bought the cheapest option.) Locally, about half is depreciation of the dishwasher and half is electricity/washing powder/water (negligible).
(I’ve brought this up before: http://lesswrong.com/lw/9pk/rationality_quotes_february_2012/5tsb.)