Updated on 09.15.11

Saving Pennies or Dollars? Extra Costs of Lunch

Saving Pennies or Dollars is a new semi-regular series on The Simple Dollar, inspired by a great discussion on The Simple Dollar’s Facebook page concerning frugal tactics that might not really save that much money. I’m going to take some of the scenarios described by the readers there and try to break down the numbers to see if the savings is really worth the time invested.

Kathy said, My husband takes his lunch almost every day to work. If my son and I go out we’ll take our lunch as well. This equates to big meal cost savings but now that we’re using TONS of tupperware to cart our bag lunches I have to run the dishwasher constantly. With water, electricity, soap, etc. Are we still coming out ahead? Is this saving us big dollars or just cents?

Let’s do the math, shall we?

To test out Kathy’s question, I took out a bunch of our own reusable containers that we use for our lunches and filled up the dishwasher with them. I wanted to see exactly how many it would take to fill up our rather typically sized dishwasher.

What I found is that I was easily able to get eighteen containers with lids into our dishwasher pretty easily. Some of these were pretty large containers, while others were pretty small, so I think eighteen is a pretty good average.

Energy Your mileage may vary somewhat, but this data indicates that the typical dishwasher uses 2 to 5 kilowatt hours per load (including heating the water). We’ll use a 3.5 kWh average. A kWh of energy costs roughly \$0.11, so the energy cost is about \$0.38.

Soap You can find soap or detergent at a lot of different prices. I was able to quickly find dish detergents and soaps that varied from \$0.10 per load to \$0.35 per load. Let’s figure \$0.20 per load.

Water The average dishwasher load uses about 15 gallons of water. Water is usually sold by the acre-foot – 325,851 gallons for \$120 (or so). You’ll end up spending a cent or two on the water depending on how your municipality taxes it.

Your cost per load of dishes is about sixty cents, all told. This means that your cost per container for running them through the dishwasher is just a hair over three cents.

Remember, each time you use a container, you’re eating inexpensive leftovers for a meal instead of eating out. You should easily be saving multiple dollars each time you use a container.

What about the cost of the containers? Unless you’re drastically overpaying for such containers, you shouldn’t have spent more than a few dollars per container. It only takes a leftover meal or two to recover the initial cost of the container.

Thus, the math pretty clearly shows that washing your own containers and using them for leftovers saves dollars, not pennies.

Of course, there is a small time investment of loading and unloading the dishwasher, but the savings for that small amount of time makes it quite worthwhile.

1. lurker carl says:

Wash the containers by hand. It uses less water and they get cleaner by not flying around in the dishwasher or nesting.

2. Pnut says:

Is it true that average dishwashers use FIFTEEN gallons? While our drain was clogged, we were draining our dishwasher into a 5-gallon bucket. It would fill once during the cycle. After the dishwasher was done we’d dump the bucket. I didn’t buy this dishwasher for its water economy and we run a “normal” cycle. Where are the extra 10 gallons being used?

3. Riki says:

I have a portable dishwasher that hooks onto the tap and drains into the sink. We tested several times (by plugging the sink to see how many times it filled up when the diswasher was draining) and it uses just over 2 sinks full of water for a full load. This is much, MUCH less water than I would use washing the dishes by hand.

4. Katie says:

How about resusable tupperware vs. wrapping leftovers/sandwiches in foil or using little sandwich bags? (Though, of course, there are environmental considerations too.)

5. rebecca says:

You are also probably eating fewer calories and less fat than most huge restaurant or fast food meals. If you are cooking from scratch your meals are also considerably higher quality for way less than a comparable meal eaten out would cost.

6. Other Jonathan says:

Regarding the point about the time cost of loading the dishwasher, I think that is FAR overcome by the time savings of not going out to eat lunch. I bring my lunch to work in tupperware every day (always delicious leftovers from home-cooked dinners) and I spend 2 minute heating my food in the microwave at work and then 10 minutes eating. I’d say each meal costs less than \$2. If I were to go out, I would have a minimum of 20 minutes just getting food every day (not counting eating time), and that’s if I only went to the places across the street rather than ever walking farther for variety. Plus, the cheapest lunch I’d find in downtown LA is maybe \$8.

7. Katie says:

I think it depends, Other Jonathan – first, if you don’t have leftovers for whatever reason, you have the additional time of making them; second, I like the excuse to get out of the office in the middle of the day. (I do try to bring my lunch, but only for financial reasons; in all other respects, I vastly prefer buying lunch.)

8. Other Jonathan says:

Katie, true, I’m just saying what works very well for me. I don’t have any need or desire to get out in the middle of the day – I don’t love walking around the city on a work day, and I’d much rather take a short lunch break and get home earlier and go for a walk in my neighborhood with my wife.

9. valleycat1 says:

TONS of tupperware? For 1 lunch, occasionally 3? Buy one larger divided lunch container for each person & wash them after each use.

I would add that not every good habit has to be justified by being more frugal.

10. JS says:

There are very few meals where doubling the batch results in a doubling in the amount of time needed to prepare the food. So planning for leftovers to use for lunch is a huge time saver as well.

11. Steve says:

I only put containers in the top rack. I don’t want them to melt. Sometimes I have to run a less-than-full dishwasher because the top rack is full but the bottom is only half full. Am I doing it wrong?

12. krantcents says:

My wife and I take leftovers for lunch. Healthier eating and saves a lot of money. In most cases, we just wash the containers by hand each day.

13. Steven says:

I’ve replaced all my plastic containers with Pyrex. They’re more durable, won’t melt in the microwave, can be used in the oven (I believe…I don’t.) The initial cost is more, but I won’t have to replace them, maybe ever, unless they break.

I also think it’s a common misconception that dishwashers use more water than washing by hand. There have been many tests which dispute this, and the comments above seem to reflect that knowledge.

14. I agree with Steven re the amount of water used. One link I saw noted that dishwashers manufactured after 1994 use 8 to 14 gallons of water, and that to receive an Energy Star rating a dishwasher must use 5.8 gallons or less.
Right now I’m visiting my dad and stepmom. Last night I did the dishes, starting with about three inches of hot, soapy water in the sink.
I washed three plates, three glasses, two glass baking dishes, a mug and half a dozen pieces of silverware. After rinsing them all, the not-very-large sink was less than one-fourth full.
That’s because I set each piece next to the sink as it’s washed; when everything is clean, I rinse everything in a slow trickle of water vs. running it hard.
While I understand that most people run the dishwasher after two or three meals, I still can’t imagine that it would take even five gallons of water to wash two to three batches of dishes.

15. Emma says:

I also have a hard time imagining that “tons” of Tupperware is getting dirty for one person and occasionally three people bringing their lunches. Invest in some nice divided boxes (one box per person) for everything that isn’t too liquid, and just rinse them by hand.

16. Lord says:

Dishwashers are rare in this country where I live (the Philippines). I remember during the time that I lived in the US (a couple of years in the 90s), I was amazed with the dishwasher. I used it for washing pots and pans – but I rarely used it for dishes ( and tupperware ). I just didn’t understand the need for it.

Trent, I have a question – is washing dishes through the dishwasher worth the time that it saves? Maybe it’s a Pennies or Dollar topic for another day.

17. Jen says:

I cringe at the thought of anyone microwaving their food in plastic!! I’m with Steven, we have replaced all our plastic with glass pyrex with lids.

18. Maggie says:

For # 11 – My daughter sells Tupperware and most of their food containers can be microwaved without a problem. Some can even be used for cooking – these are sold especially with this info. She told me that if I do not use the Heat cycle on my dishwasher (I just open the door and save the electric bill), I can wash Tupperware in the bottom rack. I have been doing that for larger pieces and have not had a problem.