Almost every home in the Valley runs its duct system through an unconditioned attic. In July that attic reaches 150–160°F. Every gap, every failed mastic joint, every boot that pulled loose from the ceiling plane is dumping cold air into that space and pulling superheated attic air back into your supply.
That's why one room is always warm, why the system runs continuously in the afternoon, and why replacing the condenser didn't fix it. We test the ducts before recommending anything, and we show you the numbers.
Signs your ducts are the actual problem
- One or two rooms run 5–8°F warmer than the thermostat's room, all summer
- The system runs nearly constantly on hot afternoons but the house never quite gets there
- Registers discharge visible dust after the system kicks on
- Bills climbed sharply without any change in equipment or habits
- You can feel air moving in the attic near the plenum or a flex run
- The house was built or re-ducted more than 15 years ago and has never been tested
Our process
1. Test and document first
Static pressure at the air handler, visual and camera inspection of the trunk and branches, attic walk-through, and leakage assessment. You get photos. We're not going to ask you to buy duct work on the strength of a technician's opinion.
2. Clean, if cleaning is warranted
Negative-pressure collection at the air handler, mechanical agitation through each branch, register and boot cleaning, and blower wheel and evaporator coil cleaning. The blower wheel is the part most companies skip and the part that most affects airflow — a loaded wheel can cut delivered CFM dramatically.
3. Seal what leaks
Mastic at plenum takeoffs, boot-to-ceiling connections, and accessible joints; replacement for flex that's torn, crushed, or has failed insulation. We re-test after sealing so you can see the before and after rather than take our word for it.
4. Balance the delivery
Sealing changes the pressure profile of the whole system. We check register temperatures and airflow room by room afterward and adjust dampers so the far bedrooms actually get their share. This is the step that turns a repair into a comfort improvement.
What this fixes — and what it doesn't
It fixes
Uneven room temperatures caused by leakage and imbalance, high runtime and high bills from lost supply air, dust circulation from attic air being pulled into the return side, and the airflow starvation that shortens compressor life.
It doesn't fix
An undersized system, a failing compressor, a low refrigerant charge from an actual leak, or a home with an attic insulation problem. If one of those is your real issue we'll tell you and quote that instead. Selling duct work to a house that needs a new coil is how the trade earned its reputation.
Frequently Asked Questions
Does duct cleaning actually do anything, or is it a gimmick?
Both, depending on who's selling it. A $79 blow-and-go with a shop vac accomplishes nothing. A real cleaning — negative-pressure collection at the air handler, agitation through every branch, register and boot cleaning, and blower and coil cleaning — removes the construction dust, drywall fines, rodent debris, and desert silt that accumulate in Valley homes. The honest answer is that duct cleaning is worth doing when there's something in the ducts, and worth skipping when there isn't. We'll run a camera and show you before you decide.
How much cooling am I losing to leaky ducts?
In Phoenix-area homes with ducts in an unconditioned attic, 20–30% leakage is common and we've measured worse. That air is being delivered to an attic that sits at 150–160°F in July, which is why the back bedrooms stay warm no matter what you set the thermostat to. It's also why the system runs constantly. Sealing is usually the highest-return HVAC dollar a Valley homeowner can spend.
Does SRP pay for duct sealing?
SRP has a Duct Test and Repair rebate that covers a portion of professional duct testing, sealing, and repair for eligible customers. That materially changes the payback math on this work. We handle the testing and documentation and can file the paperwork with you. Check our rebates page and SRP's own program page for current amounts and terms.
How do you find the leaks?
We start at the air handler with static pressure readings, then use a combination of visual inspection in the attic, camera inspection inside the trunk and branches, and pressure testing to quantify total leakage. Disconnected boots at the ceiling plane, failed mastic at plenum takeoffs, crushed flex behind stored boxes, and torn insulation jackets are the usual suspects in this valley.
Mastic, tape, or Aeroseal?
Mastic at the accessible joints, boots, and plenum connections is the durable fix and what we do by default. Standard duct tape is not a duct sealant — it dries out in an Arizona attic within a couple of seasons and peels. Where the leakage is distributed through inaccessible runs, an aerosolized sealing product can make sense; where the flex is torn or crushed, replacement is the only honest answer.
How often should ducts be cleaned?
There's no universal interval. Practical triggers: after a remodel or new construction, after a rodent intrusion, after water damage or visible mold at the coil or plenum, if registers visibly discharge dust, or if the home has an occupant with significant respiratory sensitivity. Absent one of those, annual maintenance and filter discipline matter more than a cleaning schedule.
Will cleaning fix the musty smell?
Only if the source is in the duct. Nine times out of ten in Arizona the musty smell is biological growth on a wet evaporator coil or in a slow-draining pan, not in the duct runs. Cleaning the ducts and leaving the coil dirty gets you two clean weeks. We inspect the coil and drain first and treat the source — often with a UV-C system at the coil.