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Does Humidity Affect My Air Conditioner?

It is no surprise that humidity has a significant impact on the efficiency of an AC system. When humidity is too high or low, attaining indoor comfort can be difficult. Depending on your local climate, you may find that an additional humidifier, dehumidifier or both are important components to your overall HVAC system.

What Is Humidity?

Humidity is the amount of moisture that is in the air. It is measured by percent humidity, but the actual amount of water in the air at different times of year will change with the temperature. Warm air is spaced out more than cool air, which leaves more room between air particles for water vapor. These water vapor particles must be spaced far enough apart that they don’t touch because as they are pushed together, they become too heavy to stay in the air.

As the air cools, air molecules come into closer contact, and the water molecules are crowded together. This is especially true where air comes into contact with cool surfaces, like a glass of iced tea, and the water molecules bead up and drop from the air as condensation. This is why it never feels as humid on a winter day as it does on a summer day, even when the percent humidity is the same; the percent humidity is based on the volume of water that air at a certain temperature can hold. On hot days, this is a much larger volume, and you can definitely feel the difference.

As a guideline, the relative humidity range that most people like to have in their home for comfort levels ranges between 30% and 50%. On cooler days, that number will be in the higher range, and in the summer, you may want to keep it closer to 30%.

Effects of Humidity on Air Conditioning

Air conditioners cool by removing heat and moisture from the air. As heat is pulled from the air, it is less capable of holding moisture. As this happens, water condenses on the surfaces of the air conditioner and is collected and drained out as liquid water. High humidity means that the air conditioner needs to work harder to pull water out of the air and cannot cool as quickly or efficiently. If your AC has an insufficient cooling capacity, it may have to run for long periods to cope with high humidity levels.

When it is humid, your body’s ability to evaporate water from your skin and naturally cool itself is reduced. That is why there are times you feel that your home is warmer than usual. During such moments, though you may switch on your AC, you’ll benefit minimally from it. In short, you’ll spend more on air conditioning, but you’ll enjoy less efficiency.

Humidity can have an effect on your system components as well. The condensation that can build up on cooling system components may lead to corrosion or buildup of mildew, mold or other microbes in your system. This, subsequently, can affect the system’s efficiency and your air quality.

Cooling Capacity and Air Conditioners

There is a misconception that large and powerful ACs are more efficient in cooling a home. However, this is not true. When you purchase an AC designed for more square feet than required, you’ll still experience humidity issues. AC units that are too powerful don’t run as often. Between cycles, they are missing an opportunity to eliminate moisture from the air.


One of the best ways to handle humidity issues is by installing a whole-home dehumidifier in addition to your AC system. The humidifier pulls moisture from the air, leaving your AC to spend its time cooling instead of dehumidifying. Doing this will not only make your AC more efficient, but you may find that you are comfortable with a warmer temperature setting in your home as well. This will save you money on utility bills.

Dehumidifiers work in a method similar to the condensers on air conditioners. They have condenser coils that cool the air and collect the water that condenses. Smart dehumidifiers will monitor the humidity and will only work when the air is at or above a set humidity range. Manual dehumidifiers will run nonstop when switched on, regardless of humidity level.

The water that is collected by a dehumidifier can be connected to a drain so that it can operate nonstop. Smaller dehumidifiers will have holding tanks that need to be manually emptied in order for the system to work again.


If you live in a dry climate, then your issue with your air may be one of too little humidity. One way to manage it is by using a humidifier. Similar to a dehumidifier, you can install this appliance next to the AC system. Instead of removing water, a humidifier adds moisture to the air. This prevents the discomfort of dry skin and can knock pollen, dust and other allergens out of the air for better air quality.

At Premier Indoor Comfort Systems, we offer a wide range of services. We’re your source for indoor air quality solutions, AC and heating services, air balancing, heat pump services, and commercial HVAC assistance. To benefit from our quality services in the Whittier, NC, area, do not hesitate to contact us.