Mildew returns when the level of dampness approaches 60 percent relative humidity. Unless the source of the humidity is corrected, you are in a never-ending cycle of cleaning mildewed surfaces with a chlorine solution. Dry The Air Air conditioners do a good job of removing moisture. A dehumidifier removes moisture from houses that do not have air conditioning. The water from dehumidifiers can be piped directly to a drain with a garden hose or collected in a pan that must be emptied periodically to prevent overflowing.
New models have an automatic control that warns when the pan needs emptying or shuts off the unit.
Limited maintenance includes cleaning the coil with a brush or rag and wiping the dust from the cooling fan. If the mildew appears generally throughout the house, turn on the furnace for a short time, open the windows, or turn on a circulating fan and direct it against the surfaces on which mildew is forming. A musty odor sometimes is present because damp air migrates to places such as closets or room corners with no ventilation. To dry the air in closets and other small areas, burn an electric light bulb continuously. The heat is sufficient to prevent mildew if the space is not too large.