How Do Insulation Ducts Work?

Benefits of Proper Duct Insulation

• When the duct system in your home is properly insulated and sealed, it can make a big difference in your comfort, safety and efficiency of your HVAC system and lower your energy use. Rooms will achieve the temperatures set on your thermostat more efficiently because you will reduce the loss of heated and cooled air as it travels through the ducts to vent into the rooms. Insulated ducts also make a home safer by minimizing the risks of back drafts of gases, such as carbon monoxide, from escaping from the furnace and venting into rooms through the ductwork system. You might also consider having your ducts inspected and cleaned by professionals.

Signs of Poorly Insulated Ducts

• A drafty home in winter and one that never seems to get cool enough in summer is a sign of a home that has duct insulation problems. Homeowners need to make a commitment to inspect the condition of duct insulation at the start of the heating and cooling seasons. Make that trip up to the attic and down into the basement to look for holes and disconnections around the furnace and filter slot and along the ductwork connections that lead to each vent. Shine a flashlight around the connections and vents to look for signs of mold, dust and debris buildup, and yes, even vermin and pests. These are telltale indications that the insulation and sealing for the ducts need cleaning, repair or replacement. Otherwise, you may only get 80 percent -- or even less -- of your money’s worth on the amount you spend for heating and cooling.

Insulation Fixes and Solutions

• Mastic and metal tape are good do-it-yourself fixes and solutions and available at your hardware or home improvement store. Mastic is a low-cost solution to seal cracks and crevices. It’s a thick, gluelike substance that you brush on to fill the gaps. Never use standard duct tape to make repairs. It is not effective. The adhesive will unglue or delaminate from the heat inside the ductwork. Fiberglass duct wrap products are also a good do-it-yourself insulation choice to wrap around ductwork to seal leaks and gaps. It also helps prevent condensation from developing to reduce chances for water damage and the growth of contaminants, such as mold and mildew.

High-Tech Alternative

• Aeroseal is a new, high-tech insulation and sealing system developed by the Department of Energy and Lawrence Berkeley Laboratories. Trained technicians use a computer system to detect leaks and homeowners get to see the leaks on a monitor and watch them being repaired. Technicians apply patented adhesive vinyl polymer particles to insulate and seal duct leaks. Aeroseal insulation is guaranteed to last up to 10 years. Costs vary and will depend on the number of vents and ducts that will be insulated.