How Do Air Conditioners Dehumidify?


Your air conditioner is a complicated piece of machinery based on some relatively simple processes. Even though it may seem like magic, the way that your air conditioner dehumidifies the air in your home is very straightforward. The first modern air conditioner was invented by Willis Carrier as a way to remove humidity from the printing plant where he worked. After its implementation, Carrier’s plant produced much more consistent paper dimension and ink alignment because workers were able to control the humidity in the building for the very first time.

You may not live inside a printing plant, but it’s just as important to your comfort and indoor air quality to maintain a reasonably dry environment. Most people never give a second thought to how their air conditioners manage to affect the air, but it’s simple: as your air conditioner cools the air that’s passing over the evaporator coil, the excess moisture in the air condenses, much like how water condenses on the outside surfaces of a cold glass. The condensed water vapor comes together, creating drops that soon are too heavy to remain suspended in the cool air. They drop into a pan below the coil, and run out through a drain.

When the Humidity Rises

Air conditioning does more than just keep the room cool — when it dehumidifies the air, it also helps to protect your home and destroys sources of allergens. Destructive insects are attracted to humid environments, and mold needs the same type of moisture to thrive. By running your air conditioner regularly, these common household problems often take care of themselves.

If your house feels unusually humid, it could be caused by one of a few different problems with your cooling system:

Dirty Filters.

When you forget to change your filter, you do more than just collect dust. All that dirt interferes with air flow, which reduces the amount of air that the air conditioner can cool. Eventually, this dangerous cycle can destroy your air conditioner — but before it does that, the humidity will start to rise. Check your filter monthly and replace it any time it’s clogged.

Debris in the Outside Unit.

You may be surprised at how much your outside unit is involved in the cooling that takes place indoors. When it’s clogged up with leaves, vines, grass or other debris, your air conditioner can’t shed heat as efficiently as it should. Clean your outside unit regularly with a garden hose and pull any debris away to keep it running at its best.

A Clogged Condensation Line.

A well-insulated house can be a nightmare for humidity if your condensation line is backing up. The added water on the floor of your basement or crawlspace returns to the environment as it evaporates, defeating your air conditioner’s efforts. Thankfully, a clogged condensation line is usually an easy fix. Just pour a little vinegar or bleach water into the line to kill off algae colonies and break up hard water deposits.

Low Coolant Levels.

Your air conditioner needs an optimal level of coolant to do its job properly. Too much and the system may be over-pressurized, causing failure; too little and your unit won’t be able to generate air that’s cold enough to reduce humidity levels. A licensed air conditioner technician can check your levels and inject more coolant if needed.

The Wrong Size Unit.

When your house is suddenly too humid despite a newly installed air conditioning unit, you may have accidentally installed one that’s the wrong size. An oversized unit will cycle too rapidly to remove any significant amount of moisture from the air. Bigger may have seemed better at one time in the world of air conditioning, but we’ve since learned that there is such a thing as too much. Call your installer and have him check that the unit installed is the right size for your home. (It can be easy to mix up similarly shaped units when they’re stored en masse.)

Precision Air & Plumbing September 17, 2017


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