But this year was different. In October, just as the old itchy skin problem was flaring up, an allergist I visited gave me a wonderful solution--daily warm baths and Aveeno Soothing Bath Treatment. It's been like a miracle. Not only does my skin look better, but it feels much better. In fact, my back has hardly itched, even though this winter in northern New Jersey has been about 9 percent colder than last year.
What does all this have to do with energy consumption? Well, as I took these leisurely soaks in the tub, I got to wondering, just how much does it cost to take a bath? You might be wondering, too, even if you don't have time for a bath yourself, but run one every day for one of your young kids.
The quick answer is that it's not too bad. It costs about 46 cents worth of natural gas to provide the water I need for the tub. Read on for details.
To figure the cost, we started with the basement where our hot water tank is located. A quick inspection revealed that we heat our water with natural gas, and that our 50-gallon tank consumes about 36,000 British thermal units of energy each hour.
A British thermal unit, or Btu, is a measure of heat. A candle produces 1 Btu. For more on this, see my article on the cost of drying clothes.
Here's what we did next. We made sure the gas burner under our hot water heater was not operating (it makes a kind of low hiss when it's going). We then assumed we had a full tank of hot water.
Next, I took a relaxing bath while my husband did the work. He camped out in the basement monitoring how long our water heater took to reheat the tank and shut off. The heating unit kicked on almost as soon as I started filling the tub. It stayed on for about 50 minutes--much longer than the length of my bath!
I knew from my clothes-drying article that our utility measures our gas usage in Therms. One Therm equals 100,000 Btu. So, if we're using 36,000 Btu an hour, that's 36 percent of a Therm. Our utility bill said our gas rate was $1.526 per Therm. Multiplying that rate times 36 percent gave me an hourly gas cost of about 55 cents, or 46 cents for 50 minutes.
So there you have it. Costs will vary based on the size of your tub (we have a long one in our 85-year-old house) and how hot you make your bath (mine was 106 degrees Fahrenheit, or 41 Celsius). If you heat your water with electricity, the cost will be different, and probably higher.
While 46 cents is fairly little, the impact on a monthly basis can can seem larger. Averaging about 5 baths a week comes to approximately $9.20 a month. But I include the cost of the Aveeno at about $1 a packet. So the true cost is about $29 a month. (I'll leave the cost of the water for a future post.) For me, though, it's money well spent!