How Humidity Affects your HVAC

How Humidity Affects your HVAC

We all feel the effects of the high humidity that comes along with the hot Texas summer.  What people may not realize is that humidity can have an effect on your system as well. Let us talk about fluctuating humidity and achieving the ultimate indoor temperature and comfort.

Your air conditioner and the effects of humidity

Air conditioners not only cool your building, but they also reduce humidity levels. When your air conditioner is running, the warm and humid air is blown over your system’s evaporator coils. The heat from the air is transferred to the refrigerant inside the coils and carried out of your home. When this heat transfer takes place, the moisture in the air condenses and drips off the coils.

If your system does not have sufficient cooling capacity, it will be unable to cope with the high humidity levels. Common issues associated with high humidity levels are:

  • Moist air in your building
  • Damp or musty smell
  • Windows are foggy 
how humidity affects your HVAC
Causes of high humidity
  • Oversized System – If your AC system is larger than needed, it does a poor job of effectively removing the moisture. That is because the larger system does not need to run as often, so it does not have the time to remove the moisture from the air.
  • Negative Air Pressure – A poorly designed ventilation system can cause negative air pressure to be vented from your ducts. In turn, the air tries to balance itself by pulling too much air from the outside. So, when the humidity is high, the muggy air is drawn into the building.
  • Single Speed – An air conditioner that does not feature variable speeds can cause high humidity in your building. When a single speed unit turns on, it runs at full blast then shut off. This means the unit does not run long enough to remove humidity.
  • Old Unit – As your system ages, it may not run as efficiently as it used to. You may notice inconsistent temperatures, inadequate cooling, and loss of humidity control.

A dehumidifier pulls moisture from the air before it is forced through the ducts. It can be paired with AC systems and allow you to adjust the temperature and humidity.  With proper humidity levels, your building will feel colder and energy bills will lower.  The best systems on the market have humidifiers and dehumidifiers built in and automatically adjust humidity levels.


Yes, even in Texas you can have low humidity inside your building in the winter months. A humidifier will add moisture to the air in your building and can be installed right into your system. Installing a humidifier will make your building feel warmer on those chilly winter months.

Partner with Big Fish

If you find that your building is adversely affected by humidity, it might be time to consider that your unit is failing. If your air conditioning system needs adjustment, repair, or replacement, reach out to our specialists at Big Fish.

Big Fish is a full-service commercial and residential HVAC & commercial refrigeration provider specializing in a complete range of products and services, including comprehensive year-round maintenance programs and emergency service.

Contact us at 512-653-1414 for your FREE CONSULTATION!


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