Dishwashers versus hand washing. Are dishwashers a waste of money?
I suspect that dishwashing machines are a waste of money. To wash a few plates along with the pots and pans takes only a few minutes work, but the running cost of the dishwasher is surely greater than this. Lets add up the numbers.
For this thought-experiment, we will work out the daily cost of using a dishwasher, assuming it is run once per day. We will consider normal items to be washed - plates, cups and saucers, bowls, knives and forks, some pans and cooking implements. We will assume that it's necessary to wash the pans and implements separately by hand.
We will ignore electrity and detergent costs as they are small and feature as costs for both manual and machine washing.
Cost of washing by hand
The cost of washing by hand is small and simple to determine since we have already paid the startup costs of doing the pans by hand. An extra ten minutes of work, where work is valued at 20 euros per hour is less than 4 euros. Many find dishwashing to be a pleasant activity after a meal, some do not, so the value of work may vary. For each day we will have two meals, so the total cost is 8 euros per day
Cost of using a dishwasher
- Loading and unloading work. Dishwashers must be both loaded and unloaded. You must bear the inconvenience of waiting at least one hour before unloading. On the other hand, washing by hand takes ten minutes and is finished in one go. Let's say it's 10 minutes to load and 10 minutes to unload, at best. That makes the manual work of using the dishwasher about the same as with hand washing - 8 euros per day.
- Space and complexity A dishwasher will consume at least 4 square feet in a kitchen and may get in the way as it needs to be near the sink plumbing. At 1.5 euro per square foot per month, the daily rent for this space is 20c per day. Using two methods of washing, the sink and the dishwasher, increases the complexity of the kitchen processes and diverts mental attention from other matters. This complexity might be valued at 20 cent per day
- Repairs and purchase costs Buying and repairing the machine costs money and inconvenience when it breaks down. This might be valued at 100 euro per year, or 30 cent per day.
- Fixed size Dishwashers have a fixed cost per run, but this is invariant with the amount of plates to be washed. Sometimes you must wait until the machine is full to run it, requiring more cupboard space for a supply of plates, knives and forks that will cover more than one meal. If you are cooking a large meal, it is possible that the dishwasher will run out of space. Hand washing has none of these limitations. Let's call this inconvenience 50 cents per day
- Noise. Dishwashers make an annoying sound that can last one hour. Let's say 1 euro per day for creating an unpleasant environment for one hour. ( Considering an apartment rent of 10 euro per habitable room per day, this is reasonable ).
The total cost for the dishwasher is then 10.2 euros per day
So there we have it: Handwashing 8 euros per day versus dishwasher 10.2 euros per day. Yearly saving by handwashing - at least 500 euro