Ductwork and Airflow Repair in Houston
Your AC runs fine, but the back bedroom never cools? The equipment may not be the problem. Every bit of air your system conditions travels through the ducts, and when they leak, sag or are too small for the job, some rooms get shortchanged. We repair and seal ductwork so that air ends up in your rooms, not in the attic.
Signs of a Duct or Airflow Problem
- Some rooms run hotter or colder than the rest of the house.
- Airflow at a vent or two is weak while the others blow fine.
- Dust builds up fast, or the air smells dusty when the system kicks on.
- Ducts rattle, pop or whistle while the blower runs.
- The house feels damp and sticky even with the AC running.
- The system short cycles, shutting off after a few minutes and starting again soon after.
Why Rooms Run Hot or Cold When the System Works
In most Houston homes, the ducts run through the attic, one of the hottest places on the property in summer. A leak on the supply side blows cooled air into that attic instead of your bedroom. A leak on the return side does the opposite: it pulls hot, damp attic air and insulation dust into the system. That’s where the sticky air and the extra dust come from.
Leaks aren’t the only culprit. Flex duct that’s kinked, crushed under storage or sagging between its straps chokes the airflow to the room at the end of the run, however hard the blower works.
The return side matters as much as the supply. A house with one small return grille can’t pull back the air the system pushes out, so pressure builds inside the ducts. Technicians measure it as static pressure, and it’s often what makes a return whistle or a duct pop when the blower starts. When it runs high, the blower moves less air. A furnace can overheat and trip its high-limit switch, so it shuts off early and starts again: that’s short cycling. An AC coil starved of air can get cold enough to ice over.
How can I tell whether the problem is the ducts or the equipment?
Feel the air at the vents. If it’s cold everywhere but one room stays warm, or one vent blows hard while another barely moves, the ducts are the likely suspect. If the air is lukewarm at every vent, look at the equipment first: a failed capacitor or a refrigerant leak calls for AC repair.
A technician settles it with numbers: the temperature drop across the indoor coil for the equipment, and static pressure and room-by-room airflow for the ducts.
Will a bigger AC fix a room that never cools?
Usually not. If the duct to that room is too small, crushed or leaking, a bigger unit just pushes more air down the same paths. The rest of the house gets colder while that room still comes up short. Fix the airflow to the room first, and size any new equipment with a Manual J load calculation.
Sealing, Repairing and Resizing Ducts
Most duct jobs come down to one of these three, and plenty need a mix.
Sealing
Leaks gather at the joints: where the plenum meets the indoor unit, where branch runs leave the trunk and where the boots meet the ceiling. Sealing means brushing mastic, a thick paste that dries flexible, over those seams, or covering them with foil tape made for ductwork. Cloth duct tape doesn’t last up there; its glue dries out in the attic heat and lets go.
Repair
Repair covers the damage you can see: a run that has dropped off its collar, flex duct torn by a misplaced foot or chewed by pests, a boot pulled away from the drywall, or a sagging run that needs new straps so it stops kinking. Torn insulation wrap needs patching too, or the duct sweats in the humid attic and drips onto the ceiling below.
Resizing
When one room never gets enough air, its run may simply be too small or too long. When the whole house comes up short, the return side is often undersized. Resizing means a larger run, a new or bigger return, or dampers to balance the airflow, worked out room by room. It matters most when a new system goes in, since the new unit’s airflow has to fit the ducts it inherits.
How much air can leaky ducts lose?
More than most people guess. By Energy Star’s estimate, a typical house loses 20 to 30 percent of the air moving through its ducts to leaks, holes and loose connections. In an attic, that’s cooled air going straight to waste, and every leak on the return side pulls hot attic air back in.
Can I check my ducts for leaks myself?
You can spot the obvious ones. Look for dust streaks at duct joints and flex duct crushed under boxes in the attic. Feel for air escaping where the plenum meets the indoor unit. If you go into the attic, step only on the joists or a walkway, and go up early in the morning, before the heat builds. Smaller leaks take a pressure test to find.
Dust, Dirty Ducts and When Cleaning Helps
A little dust in the ducts is normal. Heavy, dark buildup on the walls of a return plenum is not, and rust along its seams points to moisture, from a sweating duct or a drain pan that overflows. Cleaning earns its keep after a remodel, after pests have nested in the ducts, or when you can see debris at the returns. Done right, it puts the ducts under negative pressure with a large vacuum while brushes knock the dust loose.
Seal First, Then Clean
Dust that keeps coming back usually has a source. A leaky return in the attic pulls in dust and insulation fibers with every cycle, so a cleaning on its own won’t last. Seal the return side first. Then keep a clean filter in place; a seasonal maintenance visit checks it along with the coil and the blower.