September 14, 2009

Washing Dishes is Cheaper than Buying Paper Plates

In Trent's weekly reader mailbag over at The Simple Dollar he had a reader say that they thought that the cost of washing dishes was probably equivalent to the cost of buying paper plates. I doubted that so I figured I'd run the numbers and figure it out.

So, which is cheaper, washing plates or buying paper plates?

Cost to Wash plates

Based on the energy guide for a typical dishwasher the cost of running a new energy efficient dishwasher is about $35 a year to run 4 loads a week. Thats just $0.175 per load. An older dishwasher could use twice as much or more electricity so that might run $0.35 or more per load. The water used is only a few gallons and the cost of that is a fraction of a cent. So for estimating purposes we can figure that it costs $0.35 or less to run a load of dishes. I am not sure how many plates you can fit in a dishwasher. But I'd assume that I could probably get about 20 into our dishwasher. So if you wash 20 plates for a cost of $0.35 then that comes out to a cost of 1.75¢ per plate to wash. You also have to buy detergent. A $3 box of Cascade has 20 oz. and should handle 20 or more loads (I'm not sure how many loads/box but I'm guessing). So that amounts to another $0.15 per load or 0.75¢ per plate

Cost of paper plates

The very cheapest paper plate that I see for sale at Safeway or in bulk at Costco is 3¢ per plate.

So in summary:

Cost to wash a plate = 1.75¢ electricity + 0.75¢ = 2.5¢
Cost to buy paper plate = 3¢

Winner: washing plates


[edit : I forgot the cost of dishwasher soap when I first wrote the post, so I added that after the fact]

14 comments:

  1. It seems like 2.5 cents vs. 3 cents leaves too little room for margin of error (although you do account for some in your calculation, i.e. less power-efficient dish washer). If someone runs the dishwasher 5 times a week or runs them with only 10 or 15 dishes in them, then the cost of washing dishes could exceed the cost of paper plates.

    Like in rent vs. own, it seems like using regular dish is more of a preference than economics---after all, paper plates, especially cheap ones are horrible and you wouldn't want to put out paper plates when you have a guest (and it's not a barbecue that you are having).

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  2. Byung,

    Yes someone might be able to find a case where paper plates are cheaper, but I think it would really be an unlikely worst case scenario.

    I used the cheapest cost for paper plates that I could find and assumed that people had a 10 year old dishwasher. You might find a more expensive dishwasher or cheaper plates that could give paper the edge but for most cases paper is going to be more pricey.

    4 vs 5 loads a week wouldn't change the cost. I figured the energy cost on a per load basis. I mentioned running the washer 4 times a week because that is what they assume when they figure the annual costs of running a dishwasher. I took the energy costs for the dishwasher from the energy star site which assumes you run a washer 4 times a week. So if they say it costs $35 / year to operate and that assumes 4 times a week then that figures out to about 200 loads a year or $35 per year / 200 loads per year = $0.17 per load.


    Jim

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  3. You forgot about the time it takes to wash, so your wasting time instead of working.

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  4. A family like myown (3 kids, 2 adults) will run the dishwasher every day. You also did not factor in water bill, sewer bill (just as high as water) plus the energy to heat the water.

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  5. I did NOT account for the time it takes to wash dishes. That time would matter. I'm not sure how to account for it though. There are more unknown variables like how long it takes to load a dish into a dishwasher vs. throw a paper plate in the trash. Then you'd have to figure out what someones time is worth on a per second basis. How can you monetize a few seconds of your time? Considering the time it takes could definitely tilt things in the favor of paper plates.

    THe costs are per load so it doesn't matter if you use your dishwasher a lot or rarely.

    The energy guide data does account for the cost of heating water. But I did not account for the cost of the water itself. I did mention it when I said: "The water used is only a few gallons and the cost of that is a fraction of a cent." I'll go through that in detail now: A standard dishwasher load takes 3-5 gallons of water. Water usually costs around 0.1-0.2 cents per gallon. That would add about 0.01¢ per plate. So not enough to matter.

    I should also point out that I was ONLY looking at the dollar cost of the two alternatives. There are other considerations. The quality of the plates, impact to the environment and the appearances.

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  6. I see we are all a bunch of penny pinching penny counting penny lovers. Lousy economy..grrr.

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  7. something to consider....i read another article i';ll try to find and link at the end of this that says "research shows that a full load in a dishwasher uses about 37% less electricity than washing by hand, however, filling your wash/rinse basin with water and washing them like that can save up to 50% more than a dishwater....if you are strictly looking to save money, the nastiest way is as always the cheapest..

    too lazy to find, Google search under cost of washing vs dishwasher questions will find it

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  8. Sam's club has paper plates for around 2 cents a piece, which would flip the results to cheaper for disposables. I don't care about a couple cents savings either way - I car about time. Dishes were constantly causing me messes. Once i figured out how cheap I could use disposables, I went entirely to them except knives. I'm a bachelor & eat out everyday, so dishes are mosly from salads, sandwhiches & other snacks. I drink bottled water & juice from the carton, so I just use 1 cup a day for tea. I did the math & I spend about 13 cents a day on disposables which = $4/month = $50/year before even subtracting soap/dishwasher savings. For me it is a no brainer & has improved my life (sorry environment).

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  9. What happened to the initial cost of the dishwasher itself? For example, I can use the paper plates on a buy as I need basis but I need to dish out the cost of a dishwasher at least once. That should be averaged into the cost of using a dishwasher.

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  10. Mariano, I used the assumption that you already own a dishwasher and that it was a sunk cost. But you do make a good point, not everyone owns a dishwasher. Plus the extra use of the dishwasher would cause wear and tear that would shorten its life.

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  11. One has to consider that plates take a certain area of the dishwasher (bottom rack), that might be empty when the dishwasher is run.

    If you're going to wash the top with glasses and bowls anyway, you might as well use as many regular plates as necessary to fill up that empty space if you're going to have empty space in the dishwasher in the bottom rack when its run.

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  12. you must consider the price of the dishwasher, it has a limited lifespan and must be factored into the cost of washing dishes.

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  13. I love this type of math, and appreciate the time and effort you took to compute it!

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  14. 750 plates at costco for $9.99
    Thats $0.013 cents each
    Better do your homework you guys are bad example for tree huggers

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