Presidents Day weekend was a time for household activities. It's kind of humdrum because last weekend we treated ourselves to seeing The Importance of Being Earnest at the Paper Mill Playhouse, and the weekend before was an even bigger treat of spending two nights at a cozy inn in Vermont to celebrate my birthday.
So, with the whirring of the clothes dryer crowding out thoughts of Oscar Wilde, and of candle-lit dining rooms in the mountains, I started to settle back to the practical. Just how much, I wondered, does it cost to burn natural gas and churn through electricity to get our family clothes dry. The quick answer is about 25 cents for a 40-minute load. To see how we figured it out, read on. . . .
We have a gas dryer, so I had to consider how much natural gas is used to heat the air that dries the clothes, and how much electricity is needed to spin the drum that tumbles my daughter's growing collection of sweatshirts and flannel pants.
The power-usage label on the door frame of the dryer provided the starting point. It said our dryer uses 22,000 Btu an hour. A Btu is short for British Thermal Unit, and it's a global standard for measuring heat. A candle produces 1 Btu, so our dryer is harnessing the power of 22,000 candles! (Ah! Back to those candle-lit dining rooms!)
Next, I checked our utility bill for our gas rate. Our rate is quoted in Therms, another measure of heat output. A little more research showed that 1 Therm equals 100,000 Btu. So, if we're using 22,000 Btu an hour, that's 22 percent of a Therm.
The rest was pretty easy. Our utility bill said our gas rate was $1.526 per Therm. Multiplying that rate times 22 percent gave me an hourly gas rate of about 34 cents.
What I really wanted to know was how much it costs to dry one load of laundry. Our unit can dry a load in about 40 minutes. That's 2/3 of an hour, so 2/3 of 34 cents came out to 22.3 cents per load.
Almost done. We still have to add the cost of electricity. For that, we took our handy Kill-a-Watt electricity-usage meter (see earlier blog here) and plugged the dryer into it. My 40-minute load used about 2.8 cents of electricity.
The bottom line is that it costs about 25 cents to run our dryer for 40 minutes. Doing one load a day brings the cost to $1.76 a week, or $7.55 a month. Plenty of households run the dryer more than once a day, so the humble clothes dryer can end up being the second-most power hungry appliance in the house, right behind the refrigerator. (See this table for costs of running appliances).
If you have an all-electric dryer, the cost is even higher. I estimate that a dryer that uses 5,000 watts of electricity an hour costs about 57 cents for a 40-minute load.
I have a few more minutes to go before our next batch of clothes is dry. I think I'll use that time to think of Vermont.