Tuesday, February 9, 2010

A Dry Calculation

Just finishing up the laundry and wondering, how much money would we save in our lifetime if we used clothes lines instead of electric dryers?1

There are two ways to calculate this depending on whether or not you use your own electric dryer or one from a laundromat. For the laundromat, it generally costs around \$1.25 to do a load of laundry. If you do a load of whites and one load of colors each week, then you spend \$2.50 per week or \$130 dollars per year. If you live for 80 years, you’ll waste \$10,000 in your lifespan.
If you own your own dryer, it’s a little more complicated because you’re paying for electricity. A single dryer load takes anywhere from 30 minutes to one hour, so we’ll assume 45 minutes. If you do two loads each week, you’re running it for 1.5 hours. At least one reference lists a dryer’s power consumption as being about 4.0 kW. From the numbers above, we can calculate the total amount of energy used each week,

energy = (power) · (time)
= (4.0 kW) · (1.5 hours)
= 6 kW·hrs per week.

In Michigan, the cost of electricity is about 12.56 cents per kW·hr. From these numbers, we can compute the cost per week,

total cost per year = (number of kW·hrs per week) · (cost per kW·hr)
= (6 kW·hrs per week) · (12.56 cents per kW·hrs)
= 75.36 cents per week
= \$39.18 per year.

Using the same lifespan as above, you would save about \$3100 dollars in electric bills over a lifetime. In addition, you would save money by not purchasing a dryer in the first place. A quick Google product search shows that electric dryers cost around \$400. Dryers have to be replaced about once every 8 years. This means you’d need to buy about 10 dryers in a lifetime, costing an extra \$4000 dollars bringing the total savings to about \$7100.

In short, dry your clothes on a line when you can. It’s good for the environment and it can save you thousands of dollars.

[1] While researching this problem I can across a very good site here.