When people who live in arid climates talk about the heat, they often do so with the caveat that it is not so bad because it is a dry heat. There is a lot of truth in this. Hot, dry weather feels less uncomfortable than hot, muggy weather. For those who live in humid areas, an air conditioner does double-duty by both cooling and dehumidifying the air. However, often both an A/C and dehumidifier are needed to keep a home tolerable.
How humidity affects comfort
The reason high humidity combined with heat feels miserable has to do with the body’s natural cooling mechanism. Sweat cools us as it evaporates from the skin. When the air around us is high in moisture, perspiration does not evaporate as efficiently.
Besides making the air feel warmer, humidity also makes everything feel damp and sticky. This extra dampness provides a suitable environment for mold, mildew and bacterial growth indoors, which can lead to problems with air quality.
How an air conditioner dehumidifies
Your home’s air conditioner cools the air, and it pulls some moisture out. This dehumidifying effect occurs as air flows over the unit’s cold coils. The moisture from the air condenses on the coils, and the air that then flows back into the home is cooler and drier.
How a dehumidifier removes moisture
Most dehumidifiers also remove moisture from the air through condensation. In heat pump dehumidifiers, the most common type, air is drawn into the unit where it is chilled. As it is chilled, the air can no longer hold onto as much moisture and this moisture is deposited within the unit. Fresh, dry air is then circulated back into the home.
Another type of dehumidifier used in hot areas is a chemical dehumidifier. These use drying agents to dehumidify the air.
When both an A/C and dehumidifier may be necessary
An air conditioner will keep air slightly drier in the home. However, many situations require both an A/C and dehumidifier to maintain comfort in hot weather.
- When an air conditioner alone cannot keep indoor relative humidity below 50 percent. To measure relative humidity, use a hygrometer. Readings will typically vary in different areas and will be higher in rooms such as the bathroom and the basement.
- If mold growth becomes apparent in the home. If your home has plumbing leaks or other issues leading to mold growth, address these first, however. A dehumidifier can help dry the air but has limitations. Mold will still occur anywhere that is consistently damp, such as beneath a leaking sink or bath.
- The home feels damp. Since individual comfort levels vary, you may be more sensitive to humidity levels than other people. It is not uncommon to feel humidity’s effects when it reaches 40 percent. Therefore, even when the hygrometer reading shows relative humidity to be lower than 50 percent, you should consider adding a dehumidifier if you still feel uncomfortable.
- The home smells dank. Sometimes mold growth is not apparent. A musty odor in the home is a sign that mold growth may be imminent, or that it is hidden somewhere.
- On days when the home does not need cooling, the air still feels muggy and uncomfortable. An air conditioner does nothing for humidity levels when it is not in use. If you do not also have a dehumidifier, this means on those days your home’s relative humidity may increase to uncomfortable and unhealthy levels.
Choosing between a whole-house dehumidifier and portable units
Portable dehumidifiers work best in homes that need dehumidification in only a few rooms, such as the basement, a laundry room or a bedroom. These take up little space, but you must empty the water receptacle frequently. Depending on the humidity, this may mean a few times a week to a few times per day. You can cut the cost of running the dehumidifiers by choosing energy-efficient units.
Whole-house dehumidifiers are the best option if several rooms or your entire house has humidity levels consistently above 40 to 50 percent. These are connected to the HVAC system. Air flowing through the return ducts is pulled into the dehumidifier where the moisture is removed. Dry air is then circulated back through the home.
For more advice about incorporating an A/C and dehumidifier into your home and other issues regarding home comfort, please contact us at James Lane Heating and Air. We serve the areas of Wichita Falls, Vernon, Burkburnett, Graham, Iowa Park, and Olney, TX. We look forward to helping you!
