If the relative humidity in your home exceeds 55% you may be have conditions that are prime for the formation of toxic black mold. Your first step to determine if you need a dehumidifier is the use of a quality hygrometer (also called moisture meter or humidistat) in all areas of your house, including basements and crawl spaces.

Features of the best dehumidifier would be:

• Quiet operation - look for units that operate less than 55 db. The lower the better.
• Portability
• Water tank full indicator light with automatic shutoff
• Continuous drain path to eliminate the need to empty the bucket
• Washable prefilter
• Low energy consumption
• Low cost.

One unit that I found that meets all the above criteria is the Surround Air 510. It operates at a very quiet 39 db, is portable, has both a full tank indicator and a float with auto-shutoff feature. You can also connect the unit to a external drainage source to drain the water to your sanitary system or directly outdoors. The energy consumption is very low and the cost is only $199.00 as compared to between $219.00 and $499.00 for units with similar features.

If you find you have several areas with excess humidity, you may want to purchase more than one of these units. The low cost and low energy consumption features are especially attractive then. Check out other dehumidifiers, but make sure they have all of these features to give you trouble-free operation, low power consumption and quiet operation.

As a side note if your home is air-conditioned, you will find that relative humidity levels should be kept in check in all air-conditioned spaces. There may be areas that you wish not to air-condition though, to keep energy costs down, such as an unfinished basement or crawl spaces. These would be ideal areas to set up one or more dehumidifiers.