As of 2015, four of the best dehumidifiers for damp spaces, such as basements, are the Comfort-Aire BHD-651-G, the Danby DDR7009REE, the DeLonghi DD50P and the Frigidaire FAD704TDP. Units were rated on ease of setup and cleaning, size, speed and noise, among other factors.
The Comfort-Aire unit scores well on ease of using the controls and cleaning the air filters. It has two fan speeds and a timer but operates with more noise than some units. The Danby uses more energy than some units but has an easily removable tank. The DeLonghi weighs less than most other units but has a more limited range for dehumidification, between 30 and 50 percent. The Frigidaire unit makes minimal noise and can achieve a humidity range between 35 and 85 percent.
High indoor humidity can cause mold. It also causes people to be uncomfortable and exacerbates a number of health conditions, such as allergies and respiratory-tract infections. Studies have shown that bacteria and mites die off at lower humidity, according to the National Institutes of Health. High humidity can cause toxic chemicals to seep into the air at higher rates. Most of the negative health effects associated with humidity occur least often in humidity levels between 40 and 60 percent.