Why Does Ductwork “Sweat?”123

During the summer months when an air conditioning unit is keeping your home cool, you may see water droplets or condensation forming on your ductwork. This can occur when the cold air within the unit is colliding with warmer within the environment, and thus creating these droplets. And even though not all ductwork sweating is harmful, in some cases it very well can be.The sweating can drip onto both drywall and insulation, causing damage to the building material and then leading to mold growth. Excess humidity issues can also lead to widespread mold growth throughout your home, so controlling ductwork sweating can save you thousands of dollars in unwanted repairs. Here are a few ways you can prevent ductwork condensation in your home:

  • Reducing Humidity Levels: An ideal range for humidity is between 40 to 50 percent. A proper sized dehumidifier can assist in controlling humidity spikes and also dry some moisture in your basement which can lead to mold growth.
  • Ductwork Maintenance: If the air ducts in your home are older, adding insulation can significantly reduce and even stop condensation from forming. Insulating your ducts can also help with energy loss as some ductwork may have cool and hot air escapes.
  • Attic Maintenance: When ductwork runs through your attic, having a properly insulated attic can make a huge difference when controlling condensation. Upgrading your attic insulation and improving your attic’s ventilation can prevent condensation on air ducts.
  • Dirty or Blocked Filters: Not having proper air flow to your unit can not only damage the unit itself, but also cause condensation. To ensure proper airflow, replace your air filters every three months, even if you don’t see condensation on AC ducts. Doing so also improves the efficiency of your air conditioner.
  • Repairing Installation Errors: Another common cause for condensation on AC ducts is if they aren’t hung properly or are touching each other. When ducts touch each other, they create cold spots where condensation can occur. Proper installation is also important when your ductwork is installed in the attic since installation can affect how well the insulation performs.

Like anything in your home, proper maintenance can reduce your chances of failure or damage. Controlling ductwork sweating can also limit your chances of mold and water damage causing thousands of dollars in needed repairs and potentially structural issues. Having your unit serviced and your ductwork checked on a yearly basis is money well spent.

About the author: Joe Fiorilli