A general home inspection turns the AC on and off. It does not open the plenum, look inside the ducts, or go up the flue. What to check before closing, and what it costs when you do not.
A home inspector has a few hours for the whole house. For the HVAC, that usually means confirming it turns on, cools, and has a filter. The parts that cost real money after closing, the inside of the ducts, the plenum, the coil and the chimney flue, are not on the checklist. Here is what to look at yourself or have looked at before you sign.
Take the return grille off and look with a flashlight. Stained or black insulation lining means a plenum replacement in your near future. A new AC unit on the outside of the house says nothing about the plenum; the two are replaced separately and the plenum almost never is. One of our customers found this out the week before moving in with a child with allergies; the unit was three years old, the plenum was twenty.
Find where it terminates. A roof termination on a long run from an interior laundry room is a yearly cleaning item. A vent that ends in the attic, which we do find, is a fire waiting to happen.
The inspector will note whether the fireplace exists. A chimney inspection looks at the flue liner, the creosote stage, the crown and cap, and the flashing. Crown and liner repairs are among the most expensive surprises after closing, and they are invisible from the ground.
With the access panel off, a coil coated in grey felt means the system has been neglected, however new the thermostat looks.
A pre-purchase inspection of the HVAC, ducts, dryer vent and chimney in one visit, with photos you can attach to a repair request. Free when you book any service afterward; ask us about the option-period timing, because we know the clock is short.
See what Air Duct Busters customers have shared about the work completed, their experience with our team, and the service they received.
They came to do the full inspection of our HVAC system and performed a thorough inspection with photos and a very detailed list of quoted recommendations. Gary and team were punctual the 3 times they came to our home and their price was very reasonable.
Read on GoogleNoah took the time to show us photos from inside the vents and ductwork and clearly explained the level of cleaning needed and why. We really appreciated the transparency and education instead of feeling pressured.
Read on GoogleGary and the team completely overhauled and replaced all ducts, return boxes, drains, etc. for both of our HVAC systems. Timely, professional, prepared, friendly and completed the large job in record time.
Read on GoogleGary inspected the plenum, there was microbial growth in the insulation. The system was replaced 3 years ago but had the original 20 year old plenum. Gary replaced the plenum and installed a scrubber. We haven't had any allergy problems in our new home so far.
Read on GoogleShort reads from the crew: what we find in Hill Country homes, what it costs, and what to do about it.
From our job log in Bertram: 4 recent visits for chimney and fireplace, ductwork, microbial growth and air quality. Photos from the crew, work as written on the invoice.
September 7, 2026 · 2 min read
From our job log in Liberty Hill: 4 recent visits for ductwork, microbial growth and air quality, chimney and fireplace. Photos from the crew, work as written on the invoice.
September 7, 2026 · 2 min read
Noticing dust, allergies or poor airflow? Seven signs your air ducts need cleaning in Marble Falls and the Hill Country, and what to do next.
April 7, 2026 · 3 min read
Leave a number and we call you back within the hour to set a window. The inspection costs nothing and you decide afterwards.