One of the biggest misconceptions about air conditioning is that it directly produces cold air. The truth is that air conditioning works by removing heat from the air so that the air that flows out of the system is much cooler than the air being drawn in. Another thing you may not know about air conditioning is that it doesn’t just remove heat from the air but also functions to absorb much of the moisture in the air. As a result, air conditioning continuously lowers both the temperature and humidity level of the air as it flows through the unit or system.
In drier climates, air conditioning alone is usually sufficient to keep the indoor humidity level from rising too high. Unfortunately, this typically isn’t the place in more humid climates like Georgia, as air conditioning will typically never be able to remove sufficient moisture to keep the building’s humidity level in check. The main reason is that your AC will typically never run long enough to remove sufficient moisture from the air. The good news is that there are a number of options that can help you to lower your home’s humidity while also improving the efficiency and effectiveness of your air conditioning. Before discussing these options, let’s first look at how air conditioning absorbs humidity.
How Air Conditioners Remove Moisture From the Air
All types of air conditioners function in the same way by using extremely cold refrigerant to capture and remove heat from the surrounding air. This is true for central air conditioners, heat pumps, ductless mini-splits, window air conditioners, and portable AC units. Whenever any type of AC is running, cold refrigerant continuously flows through the evaporator coil. At the same time, the AC constantly draws in warm air from the surrounding area or through the return air vents and forces the warm air over the cold evaporator coil.
Due to the laws of physics, heat energy always naturally flows from a high heat area (the heat source) to any surrounding area that is at a lower temperature (the heat sink). This means that the heat energy continually flows out of the warm air and is absorbed by the cold refrigerant. This temperature difference between the warm air and the cold refrigerant is also how air conditioning removes moisture or humidity from the air.
The easiest way to understand this process is to think about what happens when you have a cold glass of water on a hot day. Whenever the glass is much colder than the surrounding air, it causes moisture in the air to condense and water droplets to form on the glass. The same thing happens when an air conditioner is running as moisture in the warm air continually condenses and collects on the cold evaporator coil. As the moisture condenses, the humidity level in the air flowing over the evaporator coil decreases.
Ideal Indoor Humidity Level
Ideally, the humidity level in your home should always be around 50%, which you can check using a portable hygrometer. Another option is to install a smart thermostat, as most of these units can also measure indoor humidity.
Low indoor humidity typically isn’t that big of an issue, but high indoor humidity definitely can be. If the humidity level rises above 60%, condensation can form on your walls and in various other parts of the home. This can lead to things like water spots on your walls and ceilings or cause paint to start bubbling, wallpaper to start peeling, or your flooring to warp. Not only can this condensation cause significant water damage, but it also creates the perfect conditions for mold to potentially start growing.
Overcoming High Indoor Humidity With a Whole-Home Dehumidifier
If your home frequently has issues with high indoor humidity during the summer, a whole-home dehumidifier can be an excellent investment. These units are installed inside your existing ductwork or mounted onto the HVAC system in a bypass duct. They work in tandem with the central AC system to remove moisture and better control indoor humidity.
Whenever your air conditioning is running, some of the warm air in the return duct flows into the dehumidifier before it reaches the evaporator coil. Just like any AC system or unit, the dehumidifier also contains an evaporator coil that has cold refrigerant running through it. When the warm air flows over the cold coil, the moisture again condenses and is removed from the air.
Whole-home dehumidifiers are extremely effective and can remove much more moisture than an AC system ever could on its own. In fact, some units can remove as much as 8 gallons of moisture from the home per day. A whole-home dehumidifier also absorbs some heat from the air and thus helps to cool the air before it flows to the evaporator coil. In this way, the unit will help lessen the strain on your air conditioning so that it cools the home more quickly and works more efficiently. Some studies have shown that a whole-home dehumidifier can help lower your cooling costs by 10% or more while also ensuring the humidity level never gets too high.
How a Variable-Speed AC Can Help Control Indoor Humidity
Whenever the time comes to replace your existing AC unit, it is important to carefully consider your options. For homes that struggle with high humidity, either a two-speed or variable-speed AC can be a great choice. Traditional AC units are only single-speed, so they always run at full power. Two-speed ACs can run at high or low power as needed, and variable-speed ACs typically have at least five or six different power settings.
The reason that two-speed and variable-speed ACs are much better at controlling humidity is that they can slow down how quickly they cool. Whenever running on a lower power setting, the unit will cool more slowly and thus run for longer periods at a time. Slowing down the cooling rate greatly reduces how much energy the unit uses. Also, it helps to maintain a more consistent temperature and prevent the house from fluctuating between hot and cold as much.
However, this does not impact how much moisture the system absorbs, as condensation will always collect on the evaporator coil at the same rate, no matter how quickly or slowly the system is cooling. The longer your AC runs at a time, the more moisture it will remove from the air, and the better it will be able to control your home’s humidity level. Since two-speed and variable-speed ACs almost always run at lower power settings except on extremely hot days, they are much more effective at controlling the home’s humidity level. These units can also greatly reduce your yearly cooling costs and improve your home’s comfort, making them well worth the investment.
At Bardi Heating, Cooling & Plumbing, our team has what it takes to help make your high indoor humidity problems a thing of the past. We offer a full range of AC and indoor air quality services, and we’re also ready to assist with any of your heating or plumbing needs. For more information on your options for controlling your home’s humidity or to schedule a service call in the Norcross area, contact us today.