Last week, I wrote about measuring the electricity my computer was using by plugging it into an electrical meter called a Kill a Watt.
This week, I decided to try my hair dryer with the Kill a Watt, and holy cow. So my computer was drawing about 92 watts. My hair dryer on low used 402 watts. Switch it to high, and it goes to 1440 watts!
Why is that number so high? Well, the hair dryer is producing heat, and that can consume a lot of electricity. Here’s a great list from the Department of Energy with the typical wattages of many appliances. Some of the big electricity users are obvious: your water heater, your refrigerator, dishwashers. But some of the smaller appliances on the list that are unexpectedly high produce a lot of heat: irons, toasters and hair dryers, for instance.
On the other hand, just because an appliance uses a lot of electricity while it’s on doesn’t mean much, because it all depends on how long you leave it on. Remember, your electric bill is based on kilowatt-hours, and that’s electric use over time. And while I use my computer for many hours a day, I typically spend five minutes or less drying my hair. So where am I using the most electricity?
Hair Dryer vs. Computer: Here’s How It Breaks Down
So, I’ve left the Kill a Watt plugged into my computer for 10 days now, and the meter shows that during that time the computer has used 13.5 kilowatt-hours of electricity.
Have I used that much electricity over the last 10 days while drying my hair? Not even close. 1.5 kilowatt-hours is a better guess, because I’ve probably spent a total of an hour* drying my hair over the last 10 days.
So, yes, I’m using far more electricity with my computer than with my hair dryer.
Want to do some more math? You can find out how all that translates to greenhouse gas emissions here.
*Update 11/26/08
OK, it’s true. An “hour” was just a lazy guesstimate on my part. I didn’t really intend to measure how long I spent drying my hair over 10 days with the Kill a Watt. I mean, these numbers are close enough, right?
But now certain family members have challenged whether I really spend only five minutes a day drying my hair. Maybe I’m using a lot more electricity with the hair dryer than what’s recorded here. All right, so now it’s on. I’m measuring the exact electricity use of the hair dryer with the Kill a Watt for 10 days to prove that yes, the hair dryer still winds up using less electricity than the computer. When I have an update, I’ll post it here. Stay tuned!
Update: 1/19/09
Well, I finally finished counting this up, and I’m happy to report that after 10 days of drying my hair, I had only spent a total of 32 minutes with the hair dryer on. The total on the Kill a watt was .68 kilowatt-hours. As expected, that’s far less than the 13.5 kilowatt-hours my computer used over a 10 day period. So yes, I use far less electricity drying my hair than I do running my computer.
What’s the point of this story? Just that if you’re trying to understand how much electricity you’re using, you need to know two things: the wattage of an appliance and how long you’re leaving it switched on. Low wattage appliances or electronics can surprise you with how much electricity they consume over time.
Photos by Megan Phelps
Megan E. Phelps is a freelance writer based in Kansas. She enjoys reading and writing about all things related to sustainable living including homesteading skills, green building and renewable energy. You can find her on Google+.
