A well constructed home is designed to keep any unwanted moisture. Unfortunately, in many cases, the source of a moisture problem is inside. Condensation can create as much water damage as a leaky roof in the average home. While contractors may pay close attention to detail during construction to prevent condensation, homeowners also need to think about condensation to prevent damage. 
The Key to Condensation is Cold and Hot:
Condensation is formed when there is contact between cold surfaces and hot, humid air. A perfect example of this is when you fill a drinking glass with ice water. The outside of your glass immediately mists up and creates droplets of water. An HVAC ductwork system is no different to this glass. When the ducts are filled with cold air, and there is humid air outside, droplets of moisture will form unless you take measures to prevent it.
While they may seem innocuous, those droplets of moisture can promote mold and mildew growth inside your drywall and insulation. It can also cause stains bleeding through ceiling and walls and over time, cause rotting and collapse of structural elements of your home. This highlights that preventing condensation is vital to the safety of your home.
Preventing condensation in your ductwork is possible with the use of special insulation. This type of ductwork insulation can also improve the efficiency of your HVAC system. If you suspect you may have a condensation problem inside your ductwork, you should have a professional HVAC specialist assess your system. You may need new insulation, or there could be gaps around collars and vents that are allowing water to form and drip through your vents. Adding a little insulation in these spots could correct the problem.
Drying Your Ducts:
If you have good ductwork insulation and you still have condensation problems, it could be due to excessive humidity levels inside your home. If you live in a particularly humid climate, this can be a daunting prospect. Fortunately, there are options available to solve this particular challenge.
The first thing you will need to look at is your air conditioner. AC systems are designed to have a dehumidifying effect as they cool the air, but there are some issues where this ability may be reduced. For example, if your air conditioner is overpowered, it may not have the time needed to properly dehumidify the air during the cooling cycle. Another possible issue is that the coils have frozen over, which has compromised its ability to draw moisture from the air. A professional HVAC specialist can assess your air conditioner to determine if there are any dehumidifying issues.
Your condensation issues may only present themselves in certain areas of your home, such as humid rooms like your bathroom, basement or laundry room. In this type of scenario, you may need to add a dehumidifier in the area to prevent the moisture from forming.
If you are concerned about condensation or have noticed droplets of water on your vents or ducts, you should speak to your local HVAC specialist. Don’t risk your insulation and home being damaged by water; an experienced HVAC technician can help to track down the underlying issue to protect your home from water damage.