Mold Damage Abatement - AC vs. Dehumidifier
South Florida's tropical climate produces, because of its high humidity, an indoor air health problem. Biological growth is common in air-conditioned buildings, where moisture in ventilation systems create ideal conditions for microbial contamination. Reliance only on AC to solve mold problems is often a mistake. When relative humidity is in the 90s, a dehumidifier is often the solution.
There are three key components to healthy air. It must be fresh, clean, and have the proper humidity (less than 50% relative humidity). Fresh outside air is rich in oxygen and flushes your home of stale air, which is full of harmful airborne pollutants.
The difference between AC and a dehumidifier is not very great. An air conditioner like a dehumidifier pulls warm moist air over its cold coils; the difference is that AC does not reheat the air before moving it back into your home. What you get is nice cold air containing less moisture. The problem is that it have a humidistat, so when the home reaches a preset temperature the AC will shut down, even though your home may still have high humidity. But more importantly, depending on when you turn on the air conditioner, it may do more harm than good. If the temperature in your humidity soaked home is 74 degrees Fahrenheit and the relative humidity (RH) is 90% and you turn on the air conditioning system, when the cool air coming out hits the dew point at about 70 degrees it's going to start raining (condensation) all over the inside of your home. So it's best to use a dehumidifier and not an air conditioning to dry out your home. The dehumidifiers job is solely to remove humidity.
Relative Humidity and Your Home
Periods of high humidity create a myriad of problems for structures and people. Symptoms of high humidity would include:
- A musty odor in your home, and/or basement and crawl space
- Allergic reactions to mold and/or dust mites
- Visible mold growth in your home, basement, and/or crawl space
- Cupped wood floors
- Feeling "sticky" or "muggy"
- Visible condensation/water stains
- Peeling wallpaper/blistering paint
What should my relative humidity be?
Every homeowner should own a hygrometer that measures temperature and relative humidity (RH). The ideal relative humidity for health and comfort is about 40-50%. In the winter months, it may have to be lower than 40% RH to avoid condensation on the windows.
In conclusion the difference between an AC and a dehumidifier is not much, but the usefulness of each system can be quite different in each situation.
