You'll remember from this post that I recently learned about the harmful effects of dry-cleaning, and decided to stop sending my clothes to the cleaners and start hand-washing them instead.
This got me thinking about my regular laundry, and in particular the dryer. I started wondering if tumble drying my clothes was something I could or should give up. I came at this from two angles:
1. A tumble dryer obviously needs power to run, but how much power do I use per dry cycle? Could I conserve power by line drying instead?
2. In my effort to increase the lifespan of my clothes so that I need to buy fewer of them, I wonder if the tumble dryer does damage to my clothes that I can't see, effectively shortening their lifespan?
Here's what I found out:
Since I now know all about kilowatt hours from my research on lights, I can use the same math to figure out how much energy the dryer uses, and what it costs me on a monthly or yearly basis.
Let's say I have a 5600 watt dryer, and my typical cycle is 45 minutes, or 0.75 hours.
5600 x 0.75/1000 = 4.2
For a 45 minute cycle I'm using 4.2 kilowatt hours. If I'm paying 9 cents per kilowatt hour (check your energy bill to determine how much you pay),
4.2 x 0.09 = 0.378
then one cycle costs me $0.38.
If I do (conservatively) two loads of laundry per week, roughly 8 loads per month, that's 33.6 kilowatt hours and $3.02 per month. For a year, it's 436.8 kilowatt hours and $39.31.
So the savings are there, but they're not massive. But what about how the dryer affects my clothes?
The Reviewed Science Blog did a study about the effects of tumble drying, and while I know from my own industry experience that different fabrics will react differently to washing and drying, their results were roughly thus:
- Both washing and drying contribute to fabric shrinkage
- Drying shrinks fabric twice as much as washing
- Tumble drying shrinks fabric twice as much as air drying
- It is the mechanical agitation, rather than the heat, that contributes to shrinkage
- Tumble drying has an adverse effect on the tensile strength of fabric (how easy it is to tear)
- Tumble drying at 150 degrees Fahrenheit only twenty times makes fabric twice as easy to tear
- Heat does make a difference in how drying effects tensile strength, where it does not affect shrinkage
- Tumble drying at low heat for shorter periods will help clothes stay stronger longer
While you won't save loads of money by switching to line drying, you will save some energy, and you'll make your clothes last longer and be less prone to tears.
I picked up this bad boy from Amazon and am going to give line drying a try for a while. I'll keep you posted on whether or not it adds hassle to the laundry routine.