The call came from Kelliwood Greens, on the south side of Katy in 77450. The homeowner’s complaint was one we hear every week: dust settling on furniture a day after cleaning, and a stale smell from the vents when the AC kicks on in the afternoon. The house dates to the nineties, and as far as anyone knew the ducts had never been opened.
Years of buildup inside the return plenum before we started.
What years of buildup actually looks like
A duct board plenum collects dust the way a high shelf does, except nobody ever dusts it. Every supply collar in this one was ringed with buildup, and the flex duct runs coming off them weren’t any better on the inside. None of it is visible from the house. You’d have to pull the return grille and stick your head in, which is not something most people do on a Saturday.
Dust packed around one of the supply collars.
Inside a flex duct run before cleaning.
The rust nobody knew about
The finding that mattered most wasn’t dust. Along the seam where the plenum meets the coil cabinet there was a band of rust, and rust in that spot means one thing: condensation has been sitting on the metal. In Katy’s humidity the evaporator coil sweats every time the AC runs. When the sealing around the cabinet isn’t tight, humid air keeps feeding that moisture, and over enough summers it starts eating the cabinet. Left alone, this is how systems rot out years before their time.
Corrosion where the plenum meets the coil cabinet.
A closer look at the rust line.
Once the cleaning was done we resealed the connections with mastic. Sealing earns its keep twice here. It stops conditioned air from leaking into the attic, and it stops humid attic air from getting pulled into the system, which is what drives the condensation cycle in the first place.
Cleaning duct board the right way
Fiberglass duct board can’t be scraped the way sheet metal can. The surface tears if you’re rough with it, and a torn liner sheds fibers into the airstream. So the work is agitation plus negative air, wall by wall, collar by collar, slower than metal duct but the only correct way to do it. By the end the board looked close to the day it went in.
The plenum interior after cleaning.
Duct board wall, finished.
A supply collar and its flex run after cleaning.
Collar connection sealed up.
Finishing with a UV lamp
Because of that rust line, which is proof moisture had been living at the coil, we recommended a twin-tube UV lamp in the plenum and the homeowner went for it. The lamp runs continuously and keeps the coil surface lit. It doesn’t clean anything, and anyone who sells it as a substitute for cleaning is selling you short. What it does is stop mold from re-colonizing a wet surface after the removal work is done. Not every house needs one. A house with rust at the coil cabinet is a strong candidate, and we said so.
The UV lamp running inside the finished plenum.
Cleaned collars with the lamp tubes in view.
While the attic was open
We also walked the trunk lines and drain runs while we were up there. Insulation intact, no crushed sections, drain pitched the way it should be. Five extra minutes that can save a ceiling stain later.
One of the insulated trunk lines through the attic.
Kelliwood and the rest of Katy
We handle air duct cleaning in Kelliwood and across Katy — Cinco Ranch, Seven Meadows, Nottingham Country and everything between. If your ducts haven’t been opened since the house was built, that alone is usually reason to look. And if you’re curious whether a UV light installation makes sense for your system, we’ll give you a straight answer either way. Free quotes on air duct cleaning: (281) 318-5155.