Day 25 - Tumble VS Line Dry

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. 

Photo: scandinavianretreat.BlogSpot.com

Photo: scandinavianretreat.BlogSpot.com

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:

ENERGY

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?

DAMAGE

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:

SHRINKAGE

  • 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

TENSILE STRENGTH

  • 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

The takeaway:

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.