HVAC Duct Leaks

Pulled or Loose HVAC Ducts

• A common source of HVAC duct leaks is located right at the connection where the flexible hose meets aluminum flashing. It is especially easy to disturb HVAC duct work when it is located in an attic that is used for storage and gets relatively heavily traffic. Run your hand around the connection between the tubing and aluminum flashing to feel for hot or cold air. The tubing will be connected to the aluminum flashing by a large hose clamp, which can be loosened to allow the tubing to be better seated on the connection. Once it is seated, tighten the hose clamp only until snug, do not over-tighten. Seal the joint with duct tape.

Punctured Duct Work

• Locating small pinholes or punctures in duct work can be a difficult task. One at a time, run your hands over your duct work, feeling for hot or cold leaks. Once found, use duct tape to spot-patch the hole. Large splits and cracks may not be repairable, in which case your best bet is to replace the duct, as you are likely losing a large amount of hot or cold air to cracks and holes that you cannot see.

Points of Friction

• When installing or replacing duct work, avoid forcing the duct work into sharp angles or around fixed objects. Over time, these bends and creases can become weak spots subject to leaks. Air friction inside of the duct will wear away at the protruding crease, creating a crack that you will not notice except for your increased energy bill.

Duct Testing

• If energy efficiency is important to you, many heating and air conditioning professionals will be able to perform an HVAC duct test on your system. They seal over your heat and air conditioning registers and pump air into your system, measuring the air pressure the system can hold. The higher the pressure, the better sealed the system. They will also be able to identify areas where you can improve your efficiency, and help you spot leaks.