How To Find Air Duct Leaks: Common Signs & Detection Tips


When the duct of your HVAC system is in tip-top shape, then you can stay comfortable at home and maintain a good & healthy indoor air quality. Ducts play a major role in distributing air from your heating, ventilation and AC throughout your indoor spaces. One of the most common problems that duct experiences are leaks, which can lead to high utility bills and discomfort alongside.

When a duct leak occurs, conditioned air leaks through gaps, cracks and the seams of the ducts. Experts suggest that most homes leak around 10 to 25% of conditioned air.

Three basic types of duct leakage

First is supply leaks, in which supply air leaks and airflow from the equipment to the living spaces decreases.
Second is equipment leakage. This type of leaks will affect the components such as coil and furnace cabinets.
Third is the return leakage. This is when unconditioned air in areas like attics and wall cavities are sucked on the ventilation system and transported back to the equipment.

Signs of Ductwork Leakage

Increased energy bills.

Have you noticed a sudden hike in your energy bills? An HVAC issue is likely causing this problem. If the air ducts start to leak, your equipment will pass the conditioned air into your basement, attic and other unwanted areas. By the way, your HVAC system will consume more energy, which in turn results in higher energy bills.

Hot and cold spots.

Other common signs of duct leaks are hot and cold spots. This will occur in the areas of your house that are harder to cool or warm than others. Air duct leaks cause this problem unless there’s a steady flow of outside air into the room or it gets direct sunlight. If there are no leakages,your cooling and heating systems can reach the desired temperatures easily.

Dust around your home.

Leaking ductwork will collect dust from other areas of your home like the basement and attic, and bring them into other rooms. This will cause allergies and bring dust around your home. If your home gets dusty easily, then inspect your ductwork for leaks.

How to Seal Ductwork Leaks

After finding air leaks, duct sealing is important for optimal home temperature. For best results, combine duct sealing with ductwork insulation.

Use either mastic or aluminum tape to seal the ducts. For mastic tape, you can use a chip brush to apply a thick layer to each duct’s seam, joint, as well as other leaking areas.

Aerosol spray is another option, the professionals use this spray for hard to reach, such as walls or ceilings. Use rubber sealant through the ducts, patching leaks from the inside out.

Finding and sealing duct air leaks is essential to make your home energy-efficient. Use a smoke test, visually inspect large tears or go for a professional leakage test to detect the leaks. After finding the leaks, make use of aluminum or mastic tape to seal them up tight. Regular maintenance of your air ducts will make it work effectively and prevent duct leakage in the future.