Should I Use Heat or Fans to Dry Basement?

Summer Basement Problems

• In warmer climates, a basement can retain moisture. The best way to prevent this is to use a dehumidifier to reduce the humidity and potential mold and mildew growth. The moist, hot outdoor air comes into the cool basement and condenses on surfaces, leaving them wet. Most have witnessed this in a basement without a dehumidifier. Everything feels damp and will smell moldy real soon.

  Using a fan in the basement in the summer is not advised since it may draw in the air from the rest of the house and outdoors and create more humidity (see Reference 1). A heater used in the summer would only make the basement hotter and cause more condensation once it is shut off.

  Keep the basement closed off from the rest of your house and the outdoor air as much as possible with tightly sealed doors and windows and run the dehumidifier periodically throughout the hottest time of the day (see Reference 1). Setting it on a timer to run for four to five hours a day is a good idea and will eliminate the need to continually monitor it. Efficiencyvermont.org suggests covering basement windows to block out some of the outdoor humidity if you don't need the daylight coming in (see Reference 1).

Winter Basement Problems

• Colder temperatures outdoors are easier to deal with. A dehumidifier is not necessary if the outdoor temperature is below 60 degrees. Fans and heaters are not needed in the winter unless you want the heat for a living area in the basement. Condensation still can develop and create wetness and moisture if you have a shower or hot tub in the basement and the moisture level is increased, just like in a closed bathroom after a hot shower. Use an exhaust fan ventilation system if showers or hot water will be causing moisture on a regular basis.

Flooded Basements

• Many homeowners will have an occasional flooded basement from a malfunctioning sump pump or sewers and septic tanks backing up in the rainy season. To dry out a wet, flooded basement, a combination of fans, heaters and dehumidifiers will dry the cement.

  First, eliminate all the standing water with a wet/dry shop vacuum or a mop. Remove any rugs or other objects, like wet boxes or furniture that may need to be put outdoors to thoroughly dry. Once the standing water is gone from the floor, set up fans (making sure the unit and plug are not in water) and run the fans, rotating locations every few hours. Electric heaters can be used once the majority of the moisture is gone from the cement. Fans will dry it out quicker, but heaters can work, also. Use a dehumidifier continuously for a few days with all doors and windows shut to thoroughly remove the moisture.

Keeping it Dry

• Continual floods in your basement may be a correctable problem. You may need to add eaves troughs or change the grade of your yard to get better drainage (see Reference 1). Hire a licensed and experienced building contractor if you suspect this is the case.