Why do My AC Vents Sweat?

Wondering why your AC vents sweat? Learn the causes and find effective solutions with Sandium. Trust our advice on AC water issues and the AC system maintenance.

Updated on Oct 22, 2023
5 min read
Why do My AC Vents Sweat?

Northern California summers is when an air conditioning unit works its hardest. You may notice visible water droplets on the air vents on really hot days. This is known as condensation or ductwork sweating. It doesn’t necessarily mean that the air conditioner is in trouble. Based on this, there may be certain areas that require your attention. Read on to know more about AC vent sweating.

Causes of Vent Condensation

Condensation gradually begins to form on the surface of the ducts as the humidity levels increase outdoors. Ductwork sweating becomes more likely when the air inside the duct is colder. This is a natural process. It’s similar to the manner in which a chilled soda starts sweating once you remove it from the refrigerator on a hot day.

Vent sweating is exacerbated or caused by the following:

  • Excessive moisture in the air
  • Poor insulation
  • Blocked ducts
  • Dirty air filters

Duct condensation can be because of leaking air from the duct. This can reduce the efficiency of your unit. Ductwork sweating is likely to become a major issue as the humidity and temperature levels rise if your ductwork is not maintained properly.

Signs to Worry About AC Vent Condensation

It’s alright to notice the occasional condensation. In relation to this, persistent ductwork sweating can result in water damage. This can also create favorable conditions for toxic mold and mildew. If you have any family member that has asthma or breathing allergies, vent sweating can make the condition worse. Mold and mildew can easily spread to other parts of the house after taking hold in a certain area.

Steps to Avoid Duct Condensation

You should choose fiberglass and flexible insulation material instead of metal if you want to avoid duct leaking and condensation. Make sure the fiberglass insulation is wrapped properly if you do have metal ducts. These are a few other steps for preventing excessive duct condensation:

  • Try to reduce humidity levels around the air ducts. You can space the ducts for ensuring air flow between them. Cover the soil for reducing moisture if there are any ducts located within the crawlspace under your house. Make sure the attic is properly insulated if the ductwork is located in the attic. You should seal all holes and cracks.
  • Unblock all vents that are restricting air flow within the system. Make sure you have them cleaned regularly. Air that is not allowed to circulate freely throughout the system becomes colder inside. This increases the likelihood of vent sweating.
  • You should always keep the air filters clean and change them when required. The standard direction is to replace filters every three months. This may need to be done sooner if you have pets or a family member with dust allergy.
  • More condensation forms within the ducting system when cold air has cracks and holes to seep out. Pressure gauge can help you find leaks in the duct. You can also place your hand on the duct to find areas where the air is escaping.

Reduced airflow and a noisy AC system along with a leaking vent are signs that you need to call an HVAC professional. There may be a pressure leak if there is a sudden increase in the condensation pool around the exterior unit.

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