Dehumidifier vs Air Conditioning: Which One Do You Need When?

  • Simon Kent
  • Date: March 14, 2023
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During warm and humid weather, both air conditioners and dehumidifiers can keep you more comfortable at home. The article below illustrates when you might need a dehumidifier or an AC unit.  

You may need both an air conditioner and a dehumidifier to keep your home at the optimal temperature and humidity level. Variances in indoor temperatures and humidity levels can vary according to seasons, indoor ventilation, insulation, and windows.

What Temperature and Humidity Levels Are Best?

According to the U.S. Department of Energy, an indoor temperature of 78 degrees is ideal during warmer months. If you live in a climate where the outdoor temperature heats up enough to cause your home to warm up past 78 degrees, you need an air conditioner. 

An air conditioner will help maintain an indoor temperature of no more than 78 degrees, as long as you program it correctly. Ideal humidity levels within your home are between 30% and 50%. Levels above 50% can cause mold and mildew to form, in addition to condensation. 

When Do I Need an Air Conditioner vs Dehumidifier?

You need to program an air conditioner to run if the interior of your home reaches 78 degrees or higher. You can either install a central air conditioning unit or use portable units for individual rooms.

Some homeowners prefer to use portable or window units for individual rooms because they don’t use a portion of the interior. However, if you have pets or are concerned about any part of the interior becoming too warm, a central unit is best.  

If you live in a seasonal climate, you will probably still need an air conditioner for the spring and summer months. You’ll need AC for the main and upper floors of your home, although you don’t usually need to cool a basement.

How Should I Program an AC Unit?

Whether you’re using a portable or central AC unit, you’ll want to set the temperature to 78 degrees. In dry climates, you might be able to get away with setting the unit to a temperature as high as 80.

You should program the AC to 78 when you’re awake and at home. While you’re away or asleep, set the temperature to bump up to 82 to 85. If you have ceiling fans, you can use those at night instead to keep cool. Alternatively, you can use a portable box or oscillating fan.

Some central HVAC systems have humidifiers. If you have one of these systems, you can set the humidity percentage accordingly.

When Should I Use a Dehumidifier vs Air Conditioning?

Some climates are prone to high humidity levels, in addition to some areas of a building or home. A basement or master bedroom connected to a bathroom, for instance, can naturally contain higher moisture levels.

If you’re in an area where humidity levels rise past 30% to 50%, you’ll need a dehumidifier. This especially applies during times of the year when the indoor temperature doesn’t rise above 75.

You can choose to run a portable dehumidifier in the room you use the most. Or, if you’re already using a central form of humidity control, you can continue with this method.

How Can I Tell if My Indoor Environment’s Okay?

You can use a combination of thermometers and hygrometers in your home. These tools will help you monitor temperature and humidity levels. You can rely on a centralized thermostat, or you can purchase combo portable units for different levels and rooms in your home.

In some instances, certain rooms will heat up faster than others. Rooms with windows that face direct sunlight will either heat up quickly in the morning or late afternoon. You can try using blackout curtains and blinds to reduce the intensity of the heat that comes in.

You might find the same to be true for humidity levels. Try installing a portable dehumidifier in your master bathroom or bedroom, as well as your basement bedrooms and rec rooms.


Whether you need an air conditioner, a dehumidifier, or both to create a sustainable indoor environment will depend on indoor conditions. Areas with high temperatures and high humidity levels will require both devices. 

However, you’ll want to constantly monitor the temperatures and humidity levels in your home.

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