How to repair an air duct leak in 4 steps

How to repair an air duct leak

To maximize the productivity and lifetime of your HVAC system, you want to ensure it remains in good condition. This means replacing filters, cleaning air ducts, insulating your home, etc. In addition, it means monitoring air ducts for leaks. And if there is a leak, you must know how to fix it. Ignoring an air duct leak will force your system to work harder, resulting in increased energy costs. You don't want that.

Here is a very simple 4 step process to repairing an air duct leak:

1. Locate the Leak

Of course, you have to locate the leak in order to repair it. The most direct way is to use your hand. You can simply wave your hand beneath each air duct register or connector to determine whether or not air is seeping through. If you can feel air then you have a leak. A properly conditioned air duct will be completely insulated, not allowing air to seep through.

A more creative approach would be to buy and use a smoke pencil. They are inexpensive; you just have to determine whether or not you feel one is necessary. A smoke pencil will reveal an air duct leak if the smoke is blowing sideways.

2. Apply Duct Tape

Okay, so now you have located the leak. Next, you need to prevent the leak from worsening by covering it with duct tape. Duct tape is not a permanent fix. Rather, it is a temporary fix while you gather the rest of the supplies to permanently stop an air duct leak. All you have to do is push the connectors together (or the split which is causing the leak) and cover it with a few strips of duct tape.

3. Apply Mastic

As the duct tape is keeping the leak secure for the time being, you will want to purchase a mastic sealant. Mastic is a type of liquid that bonds and flexes to its attached surface. Basically, it is a very strong sealant. At this point, you can remove the duct tape and apply the mastic.

The mastic layering should be at least a nickel thick. You want to pour and rub enough on the air duct leak to where it will seal the leak for many years to come. With that said, there is no reason to overdo it. You can save some in case other leaks come about. It’s best to use a cheap paint brush and spread the mastic that way. If you don’t have a paint brush then you can spread it with your hand, which should be covered with a rubber glove.

4. Cover leak with Foil-Backed Tape

Let the mastic sit for at least 10 minutes before proceeding to the next step. Once it is dry, cover the leaky area with foil-backed tape. This tape is similar to duct tape, only much more adhesive. The combination of mastic and foil-backed tape should prevent a leak in that particular area for a long time to come.

AC Repair Garland

Most air duct leaks can be handled as a do-it-yourself task. Then again, some leaks are more severe than others. If you try the above steps and still cannot prevent a leak, contact AC Repair Garland at (469) 229-7740. Our HVAC experts will have your air duct leak repaired in no time! And if a duct replacement is deemed necessary, we will take care of that for you as well. We look forward to helping you with any and all of your heating and cooling needs. For additional HVAC related input, please visit our blog.