Not only is duct sealing helpful, in situations of major duct leakage it’s a necessity. Going without it means paying more to heat and cool your house, creating extra strain on the HVAC system, a shorter life for the heater and AC, unhealthy and poor-smelling air in the house, and other problems.
We know why people wonder about the usefulness of duct sealing. It’s because ducts are hard to see. This makes it difficult to visualize the ducts needing to have any repairs in the first place. When you see damage to a wall or dying grass on the lawn, it’s a signal to do something about it. The only warning signs you’ll have that your ducts are in trouble are second-hand issues that might be from other troubles. These include higher energy bills and hot/cold spots around the house.