Leaky, crushed, or undersized ducts cause hot and cold rooms, weak airflow, dust, and higher bills. ENERGY STAR estimates a typical home loses about 20 to 30 percent of duct airflow to leaks. A contractor can test for leakage, seal joints with mastic, insulate ducts in attics and crawlspaces, and correct design problems.
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Your ductwork is the delivery system for everything your heating and cooling equipment produces. If the ducts leak, are crushed, or were undersized from the start, even new equipment will struggle. In many Metro Atlanta homes, ducts run through hot attics or vented crawlspaces, so a leak doesn't just waste air; it can pull in hot, humid, dusty air from those spaces.
Signs of duct problems
- Rooms that are noticeably hotter or colder than the rest of the house, especially upstairs bonus rooms
- Weak airflow from some vents
- High summer power bills even though the equipment seems to work
- Excess dust, or dust streaks around supply registers
- A musty smell when the system starts, or a house that feels clammy in summer
- Disconnected, crushed, or torn flex duct visible in the attic or crawlspace
How much air can leak?
According to ENERGY STAR, in a typical house about 20 to 30 percent of the air moving through the duct system is lost to leaks, holes, and poorly connected ducts. Sealing and insulating ducts in unconditioned spaces is one of the more effective ways to improve comfort and efficiency.
What a contractor can do
- Duct leakage testing. A duct blaster test measures how much air the system leaks, giving a baseline before and after repairs.
- Sealing. Joints and seams should be sealed with mastic or approved foil tape, not ordinary cloth duct tape, which tends to fail.
- Insulation. Ducts in attics and crawlspaces should be insulated to limit heat gain and prevent condensation.
- Repair and replacement. Crushed or kinked flex duct, collapsed runs, and disconnected boots can be repaired or replaced.
- Design corrections. Adding return air paths, resizing runs, or adding zoning can fix rooms that never keep up. Proper duct design follows ACCA Manual D.
- Static pressure testing. Measuring system pressure shows whether the ducts and filter are restricting airflow.
Does duct cleaning help?
The EPA's guidance is that duct cleaning has never been shown to prevent health problems, and it isn't needed on a routine schedule. It may be warranted if there's substantial visible mold growth inside the ducts, an infestation of insects or rodents, or enough dust and debris that particles blow out of the registers. Be cautious of very low-priced duct cleaning offers that turn into upsells, and ask that any company follow the EPA's guidance and industry standards.
Two-story homes
Upstairs rooms in two-story Atlanta homes often run warmer in summer because heat rises and the attic above can get extremely hot. Solutions range from balancing dampers and added returns to a separate upstairs system or a zoned system. A contractor should measure before recommending more equipment.
If rooms won't stay comfortable, request an HVAC contractor to evaluate your ducts and airflow.
Frequently asked questions
Why is my upstairs so hot?
Heat rises, attics above upstairs rooms get very hot, and many systems weren't designed with enough supply and return air for the second floor. Duct sealing, balancing, added returns, zoning, or a separate upstairs system can help.
Should I get my air ducts cleaned?
Not on a routine schedule. EPA guidance suggests considering it when there's substantial visible mold in the ducts, a pest infestation, or enough debris that dust blows out of registers.
Can I seal ducts with duct tape?
Ordinary cloth duct tape tends to dry out and fail on ducts. Mastic sealant or approved foil tape is the standard for sealing duct joints.