When a 1920s Heights bungalow runs its return air through a flex-duct line that’s been pinched against an attic truss for forty years, your blower wheel pays for it every cooling cycle. Static pressure climbs past 0.8 in. WC. The bearings start to whine. Delta-T compresses, and your two-ton system starts cooling like a one-and-a-half. That’s the kind of problem clean ductwork actually solves, and it has very little to do with the dust you can see on a vent cover.
Houston runs 75 to 90 percent relative humidity through summer. In The Heights, where bungalows from the 1920s and 1930s sit alongside new builds in the same block, that moisture finds every gap in old ductwork and every seam on a freshly installed plenum box. Hurricane Harvey in 2017 left a mold legacy across the metro that still shows up in attic ducts almost a decade later.
Pine pollen handles the spring problem. Post-build dust handles the rest of the year. If your ducts haven’t been cleaned since the system was installed, your evaporator coil is wearing a layer of biofilm that’s eating ten to fifteen percent of your cooling capacity before the air ever reaches your living room.
How We Clean — The NADCA ACR Standard
Our crew follows the NADCA ACR Standard on every job. We seal every supply register, connect a negative-air machine with HEPA filtration to the return trunk, and run a Rotobrush through every supply run and every return. The HEPA spec catches 99.97 percent of particles down to 0.3 microns. We pull the blower wheel and clean it on the bench. We hand-wipe the plenum box. The evaporator coil gets sprayed with coil-safe cleaner and rinsed. Supply boots get vacuumed individually.
Static-Pressure Verification Before We Leave
Before we leave, we measure static pressure at the air handler and document the drop. If we cleaned it right, the number drops. If it didn’t drop, we figure out why before we pack up. We’ve seen 10 to 15 percent cooling-load reductions on systems that came in at 0.85 in. WC and left at 0.55. We don’t promise a number. Every system is different. The physics is real.
