Source: Old Home Journal
Using a dehumidifier in your basement is a relatively simple and inexpensive way to effectively prevent many excess moisture problems. Dehumidifiers work by pulling air into the machine and over open refrigeration coils, where moisture in the air condensates and drips into a collection pan. Most machines are designed with a float mechanism that turns the machine off when the water collection level gets too high. Standing water, however, can promote mold growth, so make it a daily habit to empty the pan (two or more times a day is a good rule), or set up a positive drain by running a piece of garden hose into a drain, sewer line, or sump pump hole in your basement. Work to keep the humidity in your basement between 50 and 60 percent.
Dehumidifiers are sized according to how many pints of water they can remove from the air within a 24-hour period. It’s important not to purchase an undersized unit. To ensure that you buy a unit of the right capacity, consider not only the square footage of your area but also the severity of the dampness. A moderately damp room demands much less dehumidifying than a cellar of the same size with visible water penetration. Don’t forget to bring square-footage information with you to the store; it is essential in getting the right size machine. Though new units are energy efficient, you will see a slight impact on your electric bill, so it pays to get a greater-capacity unit that has to run less.
Expect to pay around $200 for high-quality machines, which can come in a variety of capacities and grades. Some industrial suppliers (such as Grainger’s Industrial Supply) also sell to homeowners and will have higher quality models than the average retailer. (Professional models also can operate at lower temperatures-down to 40 degrees, versus 50 degrees for the average residential unit). In my experience, a high-end dehumidifier not only offers better dependability and longevity, but also is quieter.