A few days ago, a friend of mine told me that she runs a dehumidifier in her laundry room because it gets fairly steamy in there at times when the washer and dryer are both running. She takes the tray from the dehumidifier and adds it to the washing machine in order to save money on her water bill.
Right off the bat, this tip struck me as being a bit out of balance. How much water does a dehumidifier really extract? How much energy does it take to continually run a dehumidifier?
I was on the case.
First of all, I wanted to know how much water a dehumidifier would extract from the air. I checked out the Energy Star site on basic dehumidifiers and found that if we assume the room is very damp and is 500 square feet in size (which is substantially larger than the laundry room likely is), the dehumidifier will extract 12 pints of water from the air every 24 hours. In reality, I’d assume that the water extraction is less than that, but I’m going to give her argument the benefit of the doubt.
How much energy does a dehumidifier use? The Otter Trail Power Company suggests that a typical dehumidifier uses 350 watts. In other words, over a 24 hour period, a dehumidifier would swallow down 8.4 kilowatt hours of electricity.
Now, how much do these things actually cost? Tap water, for example, is typically sold by the acre-foot, which is 325,851.429 gallons of water. You can get lots of different estimates on the cost of that amount of water, but we’ll use $700 as a rough average. This gives a per-gallon cost of water from your tap as $0.002 per gallon. In other words, five gallons of tap water costs about a penny. Since the dehumidifier extracts 12 pints from the air every 24 hours, it’s extracting roughly 3/10 of a cent worth of water every day.
On the other hand, a kilowatt hour costs roughly 11 cents to purchase. Over that same 24 hour period, the dehumidifier is eating up 92.4 cents.
In other words, if she’s running the dehumidifier solely to save money on her water bill, this is an enormous loss. (That’s not to say that she’s not running the dehumidifier for other purposes. If she is, and the washing machine is the most convenient place to put the wasted water, then it’s probably a good choice.)
The point of this article isn’t to say that dehumidifiers are a waste of money. They often do a valuable job of keeping a moist room dry and mold-free, something that can add up to a lot of damage over time. The point is to simply say that tips that seem smartly frugal on the surface can actually be big losers in reality.
Trust me: over a given year, I hear a lot of frugality tips. Some of them are excellent. Some of them are mediocre. Some of them are just flat-out wrong. Here are some general principles I’ve found that help me quickly assess whether the tip is worthwhile.
Be wary of any tips that require very regular action. If you have to do something every single day in order to save money, it should be a large savings or else the hassle won’t be worth it.
Be wary of water conservation tips. Water conservation tips are generally only worthwhile if they involve something you’re already doing and also involve only a one-time change, like installing a new shower head, setting up a rain barrel for yard watering, or putting a full water bottle in your toilet tank. Most other water conservation tips just don’t work – or aren’t worth the time invested – simply because water is so inexpensive. That’s not to say there isn’t an environmental reason to do them.
Be wary of any tips that don’t match how you live. A great example of this is a programmable thermostat. If you don’t leave the house regularly every day, it probably won’t be worth it. If you’re the type that’s constantly adjusting the thermostat up and down a few degrees, it won’t be worth it. Programmable thermostats work when you’re happy within a broad temperature range and tend to leave the house a lot.
Be wary of any tips that introduce new costs. For example, if you need to buy something to save money, run the math. If you need to use more energy to save money, do the math first. Savings usually come from reduction, not from addition.
What you’ll often find is that any long set of frugality tips will cause at least one of these “red flags” to pop up for you. For each person, though, different tips will cause different red flags. That’s to be expected, because we all live different lives. The key, as always, is to find the tips that work for you.