Tips on Insulated Flexible Ducts

Air Leaks

• Leaking ductwork will cause a significant reduction in the efficiency of your heating and cooling systems, costing you money. These leaks commonly occur at the joints and connections in your ducting. Check the return and supply registers throughout your home to make sure that there are no gaps between the duct and the register. Leaks can also occur as a result of punctures in the insulation and liner of your ducts. If you find a leak or gap in your ducts, you can patch it using metal foil tape with an acrylic or mastic adhesive. This type of tape will adhere to your ducts more effectively and last longer than common duct tape.

Placement

• The location of your ducts can have a significant effect on their performance. Ducts are often installed in the unheated areas of the home below the sub-floor or above the rafters. Adding more insulation to your ducts can improve the efficiency of your heating and cooling system. The Virginia Tech Cooperative Extension recommends adding between 1 1/2 and 3 inches of insulation. Ensure that the flexible ductwork is not crushed or malformed under the weight of additional insulation because this will decrease your HVAC system's effectiveness.

Contaminants

• Over time, flexible vents can collect significant amounts of dust. The majority of this dust remains trapped in your vents. However, if moisture is introduced into dirty vents, they can become a breeding ground for mold. Mold growing in the drain pan of your HVAC unit and moldy odors coming from your registers are common signs of a mold problem in your ducts. The insulation surrounding your vents is also prone to mold if it is exposed to moisture. If this insulation becomes moldy, you will have to replace it.

Preventive Measures

• You can take several measures to prevent the growth of mold in your ducts. Your flexible ducts need to be stretched taut and shouldn't have any unnecessary curves. Dust and dirt often accumulate at bends in flexible ducts or in wrinkles in the ducting. Regularly check your air filter and replace it to reduce the amount of dirt that is allowed into your ducts. Do not allow any persistent leaks around your ductwork and ensure that the drain pan for your heating and air conditioning unit does not have standing water in it. Take notice of where your heating and cooling system takes in air and try to limit activities such as hot showers, boiling water or operating humidifiers that increase the humidity in that area.