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§ 02.01Ductwork + ventilation — TX + OH

Half the no-cool calls are a duct problem. Not the unit.

Twenty minutes on site gets you a real leakage number in CFM. We will tell you whether sealing, balancing, or replacement makes the math work — before anyone writes a bid for a new unit. We won't sell you equipment when a duct fix solves it.

Sealed and insulated duct trunk in an attic — mastic at every joint, R-8 wrap holding
In the attic · Allen, TXMastic-sealed joints, R-8 wrap, and a return plenum that no longer pulls attic dust through the filter slot.
Day-one test protocol

Four numbers before any quote.

We arrive with calibrated instruments — not a clipboard and a hunch. Twenty minutes on site delivers four hard numbers that tell us whether the problem is the equipment, the ducts, or the way they were sized.

01

Static pressure

UnitinH₂O
Target0.5–0.8 typical

A magnehelic gauge reads the supply and return pressures the system fights against. High static pressure is the duct equivalent of a clogged artery — the equipment will burn out trying to push past it.

02

Total leakage at 25 Pa

UnitCFM₂₅
Target< 4% of system airflow

A calibrated blower pressurizes the duct system to 25 Pascals — the standard test pressure for residential ducts. The fan reports the cubic feet per minute it has to push to hold that pressure. That number is your leakage.

03

Room-by-room CFM

Unitcubic feet per minute
Targetmatches fresh Manual D

A flow hood at every register confirms each room is getting the airflow the load calculation says it needs. A 200 CFM bedroom that reads 90 CFM is why the master is always 8° warmer.

04

Visual scope + smoke pencil

Unitphoto + report
Targetevery joint, every accessible run

A neutral-buoyancy smoke pencil makes leaks visible at the joint. We photograph every problem location, mark it on a duct map, and the package goes home with you whether you sign or not.

Failure mode atlas

Where the air goes when it shouldn't.

The leak rarely lives where you'd expect. Five places account for the bulk of the losses on a typical attic duct system — and they look the same in Texas as they do in Ohio. We mark every problem location on a duct map; you keep it whether you sign or not.

AIR HANDLERAA · plenum seamBB · boot dropCC · flex collarDD · return gapEE · crushed runATTIC · 130°F SUMMERCONDITIONED ROOM
Typical attic duct system in a 1990s–2010s residential build. Five marked points cover most of the leakage we measure in the field.
  1. Plenum-to-trunk

    The cabinet seam where the air handler meets the supply trunk. Almost always loose on a 10-year-old install. First thing we tape and mastic.

  2. Boot to ceiling

    The drywall cut around the register boot is rarely sealed. Conditioned air leaks into the wall cavity instead of the room. Caulk-and-mastic fix.

  3. Flex-duct collar

    A zip-tied collar with no mastic over the inner liner. Loosens with every thermal cycle. Re-strap, mastic the joint, re-insulate.

  4. Return plenum gap

    A gap at the return pulls dirty attic air past the filter. The single biggest dust + allergen win on most older homes — sealed before any filter upgrade.

  5. Crushed flex run

    A flex line crushed by stored insulation, attic walkboards, or a contractor who went through later. Replace the run; sealing a kinked line is wasted mastic.

Sealing methods · field reference

Four ways to seal a duct. Three of them shouldn't be the default.

Mastic is the house standard on every job. Foil tape supplements it on rigid metal seams. Aerosol sealing comes out for the trunks we cannot reach by hand. Duct tape never leaves the truck — it only buys silence on the leak you came to fix.

Method
Never on the truckDuct tape
On rigid joints onlyFoil tape
House standardMasticOur pick
Inaccessible runsAerosol
Lifespan in attic heat
12–18 months
5–10 years
Life of the duct
10+ years
UL-181 listed
No
Yes (when rated)
Yes
Yes
Fixes existing leaks
Hides them
Yes, on clean surfaces
Yes — bridges + seals
Yes — from inside
Real-world cost / ft
$0.10
$0.45
$0.80
$3–6
Our verdict
Will fail by year 2
OK for rigid metal seams
Default on every joint
Best for buried trunks

On every replacement and most repair scopes, you will see mastic at every joint, foil tape on accessible rigid metal seams, and aerosol on any buried trunk we cannot reach by hand. The duct tape you may have spotted in the attic gets pulled and replaced.

Climate-aware duct insulation

Same fan. Different attic. Different spec.

The duct insulation spec changes by 4 R-values between a Texas attic and an Ohio one. Default below code is how a 20-year-old install loses 8°F to the attic on the way to the bedroom. We spec to climate, not to whatever was on the truck.

Texas attics

Insulate to keep cooled air cooled.

Design day
+103°F design day
Attic peak
130°F summer attic
TierR-value
Code minimumR-6
Our defaultR-8
Premium upgradeR-10

A duct in a Texas attic loses cooled air to a 30°F gradient — supply air at 55°F, attic at 130°F. Below R-8, the duct itself becomes a heat exchanger and the air arriving at the register is 8–12°F warmer than what left the unit. That is the room that is "always 8° too warm."

Ohio attics

Insulate to keep heated air heated.

Design day
+5°F design day
Attic peak
20°F winter attic
TierR-value
Code minimumR-6
Our defaultR-8
Cold-climate upgradeR-12

In Ohio the gradient flips. Supply air at 110°F, attic at 20°F — heated air loses 90°F worth of comfort to the duct walls if the insulation is not there. Cold-climate replacements default to R-8; we step to R-12 on long trunk runs and any duct that crosses an unconditioned chase.

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§ 06Reach the dispatch desk

Test first. Quote second.

A 20-minute pressurized duct test, a fresh load calc, and an itemized scope — seal, rebalance, or replace. You decide what gets done. The number on the test report is the number on the invoice.

(214) 578-9961