Plenum & Return-Box Cleaning in San Marcos
Deep cleaning of the distribution boxes at your air handler.
01San Marcos — the housing record
What San Marcos actually has behind its walls.
Before anyone quotes a duct job here, this is the stock they are quoting against. It is public Census data, and it is different in every city we cover.
- Housing units
- 29,892
- Built pre-1980
- 15%
- Built 2000s
- 30%
- Built since 2010
- 31%
- Gas heat
- 26%
- Electric heat
- 71%
- Single-family
- 34%
U.S. Census Bureau, American Community Survey 5-Year Estimates (2023), tables B25034, B25040 and B25024. Percentages are rounded and describe the city, not your house.
What that means for ducts
New-build ductwork
Roughly 31% of San Marcos's homes were built since 2010. New does not mean clean: the commonest thing we pull out of a five-year-old system is the construction phase itself — drywall fines, sawdust, insulation fiber — plus builder-grade flex that was kinked or crushed on the day and has been throttling that run ever since. Photographs matter more here, not less.
That is a reading of the city’s stock, not a diagnosis of your home. Which of it applies to you is exactly what the camera settles — and why we would rather run one than quote from a postcode.
02Working in San Marcos
The part that changes from street to street.
Two thirds of the housing in San Marcos is not a detached house, and most of that is built for students, which changes both what the system looks like and who is able to do anything about it. In a purpose-built block the unit has a closet air handler, a short run to each bedroom and one return grille, and per-bedroom leases put four adults on four different schedules through the same system for nine months. There is very little duct in play. What matters is whether the filter is the right size and actually seated, and what the coil and drain pan in that closet look like, because in Hays County humidity that is where anything biological begins. Heat is electric nearly everywhere here, so there is no furnace and no flue to inspect. The other San Marcos case is the older neighborhoods off the square, family houses now leased by the room, carrying far more occupancy and far more moisture than the system was ever sized for.
the headwaters at Spring Lake
- Texas State / The Square ·
- Blanco Vista ·
- Kissing Tree ·
- Willow Creek
County
Hays County
Same standard in San Marcos as everywhere else.
Source removal to the NADCA ACR standard, a written quote before anything is touched, and camera photographs of your own runs before and after. We are not going to re-argue that on every city page — it is set out once, in full, on the service page.
- Supply and return plenums HEPA-vacuumed and hand-wiped
- Liner and insulation condition inspected and photographed
- Access panels resealed with UL 181-listed foil tape
- Fresh filter installed on request
- From
- $199
- On site
- 1–2 hours
- Scope
- 4 lines
Prices shown are starting estimates and may change with the condition, access, and scope we find on site. Only a written quote from an on-site visit is a price we commit to.
03Plenum & Return-Box Cleaning — in this stock
Cleaning a system that is still carrying its own build.
A post-2010 system is usually not dirty in the way people picture. What comes out is the construction phase — drywall fines, sawdust, insulation fiber — that was pulled into open ducts before the house was ever occupied, plus whatever a kinked flex run has been collecting behind the crimp. That is a different cleaning: shorter, more targeted, and far more dependent on the before-and-after photographs, because the difference is not something you can smell.
What if the plenum liner is in bad shape?
We stop and show you rather than bill for a cleaning that can't help. Degraded or moldy duct-board liner can't be restored by cleaning — EPA guidance is clear that porous materials in that condition need replacement, which is HVAC-contractor work.
Can you clean just the plenums without doing the whole system?
Yes — that's precisely what this service is. The plenums are the highest-traffic surfaces in the system, so cleaning them alone delivers outsized value on older systems, from $199.
04Book in San Marcos
Three fields, and a person calls you back.
Tell us the ZIP and we will tell you what your system likely needs — including, sometimes, that it needs nothing yet. Nothing is charged until you have approved a written quote.
05Questions
Asked in San Marcos, answered straight.
What if the plenum liner is in bad shape?
We stop and show you rather than bill for a cleaning that can't help. Degraded or moldy duct-board liner can't be restored by cleaning — EPA guidance is clear that porous materials in that condition need replacement, which is HVAC-contractor work. Our photos give you exactly what that conversation needs.
Can you clean just the plenums without doing the whole system?
Yes — that's precisely what this service is. The plenums are the highest-traffic surfaces in the system, so cleaning them alone delivers outsized value on older systems, from $199. If the camera later shows the runs need work too, that's a separate, honest conversation with evidence attached.
We manage student units. What is actually worth doing at turnover?
Open the closet, not the duct. Pull and photograph the coil, flush the condensate line, confirm the filter rack seals and note the condition of the pan. In a unit with fifteen feet of supply, a duct cleaning is close to theater and the coil is where the complaints come from. If a specific unit shows debris at the registers we will say so and treat that one.
Our apartment smells musty when the AC starts and the office says the ducts need cleaning.
Ask for the coil and drain pan to be checked instead, in writing. Odor that appears in the first minute of a cycle and then fades is the classic signature of a wet coil, and it is a maintenance item rather than a duct job. Putting it in writing matters more than the wording, because a comment at the leasing desk creates no record.
We rent an older house near the square with five of us in it.
The system in that house was sized for a family and it is now working against five people's showers, cooking and laundry. High occupancy raises the moisture load faster than the dust load, so the honest priority is humidity and return capacity, not cleaning. We would rather measure it and tell you the equipment is outmatched than sell a service that changes nothing.
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