While homeowners in many parts of the United States use air conditioners to cool off, homes in Southwestern states often rely on moisture from evaporative coolers. These devices, commonly known as swamp coolers, need as little as 20 percent of the electricity needed to run an air conditioning unit, according to the U.S. Department of Housing and Urban Development. However, swamp coolers can fall prey to mold buildup that threaten occupants' health.

...
Mold can grow within a swamp cooler's components.

Components

Swamp coolers have the potential to harbor mold at any of several points in their structure. The system consists of a central unit with a belt-driven fan and a cellulose pad that remains wet because of water pumped from the home's water supply. This unit then connects to the rooms in a house through ducts. Any of these components could experience a buildup of mold on the surface either from the moisture content of the air or from the water itself.

Operation

A water pump directs water to the cellulose pad to keep it damp. The fan continuously blows dry, warm air over the moistened pad. According to the California Energy Commission Consumer Energy Center, the dry air takes up some of the moisture and cools as it passes over the pad before continuing on its way to all parts of the home. While this process works well in relatively dry environments, a swamp cooler left to run for several humid days will begin to smell from mold buildup as the saturated components begin distributing mold spores through the ducts.

Consequences

The U.S. Environmental Protection Agency states that mold growth inside a home can cause a variety of health problems, specifically mentioning swamp coolers as one cause. People with mold allergies may experience skin or eye irritation, nasal congestion, fevers or wheezing. People who suffer from lung disease may experience lung infections as the mold invades their respiratory systems, while asthma patients may develop serious breathing problems.

Cleanup

Homeowners with swamp coolers who smell the musty presence of mold or experience reactions to airborne mold spores should have the swamp cooler cleaned to remove any mold deposits, according to National Allergy, a company that makes products to alleviate allergy problems. Cellulose pads infiltrated with mold may require replacement. Moldy ducts call for professional mold remediation, since the procedure will kick up mold spores and other allergens, temporarily making a dwelling unsafe. A High Efficiency Particulate Arrestor, or HEPA air cleaner, removes these toxins from the air within 24 hours.

Prevention

Because of swamp coolers' introduction of extra humidity into the air, the U.S. Department of Housing and Urban Development advises homeowners living in humid regions to install a conventional air conditioner instead. Swap cooler owners should open their windows just enough to allow air to flow through the home and keep the moisture level under control. Regular preventative maintenance can help ensure that a swamp cooler operates correctly, reducing the risk of mold problems.