Ductwork Repair, Sealing, and Replacement in McAllen, TX

Sealing, repair, and redesign for ducts that are wasting cooling in a superheated attic.

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Ductwork Services in the Rio Grande Valley

Ductwork is the part of the system nobody sees and almost nobody thinks about. It is also where a large share of Valley cooling problems actually live. A perfectly good five ton air conditioner connected to a duct system that leaks a quarter of its air into the attic is delivering something closer to four tons into the house, and paying full price for five.

Two problems are especially common in this region. The first is leakage at plenum connections, takeoffs, and joints, often where duct tape was used decades ago and has long since dried out. The second is undersized returns, which is endemic in older housing stock: the supply side was expanded over the years but the return never was, so the blower fights against high static pressure permanently.

A&A HVAC LLC inspects, seals, repairs, redesigns, and replaces duct systems, and we measure static pressure before and after so the improvement is demonstrated rather than asserted.

Symptoms to look for

If you recognise more than one of these, it is worth having the system looked at before it gets worse.

Some rooms never cool no matter how low you set the thermostat
Dust reappears within a day or two of cleaning
Electric bills are high relative to the age and rating of the equipment
The system runs almost continuously in summer
Rooms with closed doors get noticeably hotter
Whistling or roaring from vents or the return grille
Visible disconnected or crushed flex duct in the attic
The attic feels like air is blowing into it near the ducts

Common problems we find

These are the causes that come up most often on Rio Grande Valley systems, and why our climate produces them.

Leaking joints and takeoffs

Connections at the plenum, at branch takeoffs, and at boot connections are where leakage concentrates. Duct tape fails within a few years in attic heat, which is exactly why the industry moved to mastic and foil backed tape.

Undersized returns

Extremely common in older Valley homes. A system that cannot get air back struggles no matter how good the equipment is. Symptoms include high static pressure, noisy return grilles, frozen coils, and rooms that will not cool when doors are closed.

Crushed or kinked flex duct

Flex duct laid across a joist, kinked around a corner, or compressed by stored boxes loses a large fraction of its airflow. This is the single most common cause of one hot room.

Disconnected ducts

A branch that has separated from its takeoff pours cooled air into the attic. The affected room simply stops getting air, and the homeowner usually blames the equipment.

Missing or degraded insulation

Duct insulation that has been compressed, torn, or has fallen away lets attic heat into the air stream directly. In a 140 degree attic that transfer is fast.

Poor duct design

Runs that are too long, too small, or full of unnecessary turns starve the far rooms. Sometimes the honest answer is redesign rather than repair.

Ready to get this fixed?

Call A&A HVAC LLC and describe what is happening. We answer 24 hours a day.

(877) 237-1820

How we handle ductwork services

Nothing gets replaced until we know what failed and why. You approve the price before work begins.

Static pressure measurement
This tells us whether the duct system can move the air the equipment needs. High static pressure is the fingerprint of undersized ducts or a restricted return, and it explains a surprising number of complaints.
Attic inspection
Every accessible run is inspected for disconnections, crushing, insulation damage, and leakage at joints and boots.
Room by room airflow check
We confirm which rooms are actually short of air rather than relying on the homeowner's impression alone.
Sealing with mastic
Joints, seams, takeoffs, and boot connections sealed with mastic or foil backed tape, not cloth duct tape, which fails in attic heat.
Repair, resize, or replace
Crushed runs replaced, undersized returns enlarged, and poorly designed systems redesigned where that is what the numbers call for.
Verification
Static pressure and room airflow measured again after the work so the improvement is documented.

Why choose A&A HVAC LLC for ductwork services

Static pressure measured before and after, so results are shown rather than claimed.
Mastic sealing, not duct tape, because attic heat destroys cloth tape within a few seasons.
We fix undersized returns rather than treating the symptoms they cause.
Duct evaluation included with every replacement estimate, before you buy equipment.

Frequently Asked Questions

Questions we are asked most often about ductwork services in McAllen and the Rio Grande Valley.

How do I know if my ducts are leaking?

Common signs are rooms that never cool properly, dust that returns within a day of cleaning, high electric bills relative to the equipment's rating, and a system that runs nearly continuously. A technician confirms it by measuring static pressure and inspecting the accessible runs, and in some cases with a duct leakage test.

Is duct sealing worth it in the Rio Grande Valley?

It is one of the higher return improvements available here, and often a better use of money than upgrading equipment efficiency. Because Valley attics regularly exceed 130 degrees, every cubic foot of air lost from a supply duct, or pulled in through a return leak, costs much more than the same leak would in a mild climate.

Should I replace my ductwork when I replace my AC?

Not always, but it has to be evaluated first. Ducts that are badly leaking, undersized for the new airflow, or poorly designed will hold back any new system. Partial repair plus sealing is often enough. What you should not do is buy new equipment without anyone having looked at the ducts.

What is duct sealing and how is it done?

Mastic, a thick sealant, is applied over joints, seams, takeoffs, and boot connections, sometimes with mesh reinforcement over larger gaps. Foil backed tape is used where appropriate. Cloth duct tape is specifically not used, because it dries out and releases within a few years in attic temperatures.

Can leaky ducts make my house dusty?

Yes, and it is one of the clearest signals. Return side leaks pull air from the attic, which brings in insulation fibers, dust, and whatever else is up there, then distributes it through every room. Sealing the return side usually produces a visible reduction in dust.

How long does duct sealing take?

Most residential duct sealing jobs are completed in a day. Full duct replacement in an average Valley home typically takes one to two days depending on the size of the system and attic access.

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Reviewed by the A&A HVAC LLC service team, licensed HVAC technicians serving McAllen and the Rio Grande Valley.

Last reviewed for accuracy on August 2, 2026. Guidance here is general. Diagnosis of your specific system requires an on site inspection.

Need ductwork services in the Rio Grande Valley?

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Address, hours, and directions