Whole-system duct and dryer vent check with before-and-after photos - you see exactly what came out of your vents
That "$99 whole-house special" is a bait ad - the real number appears once they are in your hallway, or the "clean" is a shop-vac at the register. We photograph the inside of your ducts before and after instead.
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After
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AfterFast, Reliable Duct Repair & Sealing Across Sterling
Duct repair and sealing in Sterling, VA typically runs $280-$750 for most residential jobs, with flex duct replacement at the higher end and spot sealing with mastic at the lower. We dispatch crews to Sterling from our Washington, DC coordination office, and most Sterling appointments are scheduled within 3-5 business days. Call (240) 771-1508 for a written estimate before any work starts.
We’ve been working in Sterling since 2013, and the pattern is consistent: homes built during the Dulles tech-corridor boom have original flexible ductwork now well past its service life. Our Duct Repair & Sealing crews know the difference between a duct that needs cleaning and one that needs to be pulled and replaced. We document both with photos.
Why CleanRun Air Duct Cleaning Ashburn Is Sterling’s Preferred Duct Repair & Sealing Company
Sterling homeowners research before they call. We built our process around that.
Every job starts with a written price under Haven Standard Clause 1 - no exceptions, no “call for a quote.” Our technicians are background-checked and uniformed under Haven Standard Clause 3: Verified Crews, and we publish our license number on every page so you can verify credentials yourself. The 365-Day Done Right Promise is backed in writing, not buried in a policy manual.
Our documented photo record shows you what we found inside your duct runs, not what we claim to have done. In Sterling specifically, we’ve served homes from Moorefield Village to Potomac Green, and the photo records from this area show a distinctive pattern: dark particulate coating on duct boots and trunk lines that we don’t see in our Ashburn or Leesburg jobs.
Scheduling is coordinated from our DC metro office, with crews serving Sterling locally. Calls are answered by a live person, and we offer a Free Second Opinion on any competitor’s written estimate.
Our Duct Repair & Sealing Services in Sterling
Duct Sealing
Most Sterling homes lose 20-30% of conditioned air through leaks at trunk-line penetrations, register boots, and disconnected collars. We seal with mastic compound, not tape - mastic remains flexible and airtight for decades, while duct tape dries and fails. In Sterling’s older flex systems, we regularly find the original sealant at the air handler has cracked or separated entirely, pulling attic air into the return side. A typical duct sealing job in Sterling runs $280-$450 for a single-system home.
Flex Duct Repair
Sterling’s housing stock - Broad Run Farms, Potomac Falls, the Dulles-area subdivisions along Loudoun County Parkway - was largely tract-built between 1987 and 2002 with builder-grade flexible duct. That flex is now 25-35 years old. It sags between joists, kinks at pinch points, and collects compacted debris at low points where airflow stalls. Micro-tears in the inner liner let insulation fibers and attic air into the airstream. We pull the damaged run, install new flex with proper support straps, and reseal the trunk penetration. Flex duct repair in Sterling typically runs $340-$620 per run, depending on attic access and length.
Metal Duct Repair
Some Sterling homes, particularly earlier builds in Broad Run Farms and select Potomac Green townhouses, have galvanized steel trunk lines. These corrode at seams and can separate at joints under thermal expansion. We repair with metal screws, mastic, and reinforcement mesh where needed. Metal duct repair in Sterling runs $380-$750 for accessible trunk sections.
Duct Insulation
The DC metro’s humid summers - 70-80% relative humidity through July and August - mean condensation forms on poorly insulated flex duct in unconditioned Sterling attics. That moisture creates a persistent mold-risk environment. We re-insulate with R-6 or R-8 foil-faced insulation, sealed at all seams with mastic. Duct insulation in Sterling typically runs $420-$680 for a full system, or $180-$320 for targeted problem sections.
Mastic Sealant Application
Mastic is the standard for durable duct sealing, and we apply it to every penetration, joint, and boot connection we touch. In Sterling’s older systems, we often find previous repairs done with foil tape or mesh tape that has completely failed. We remove the old material and apply fresh mastic. This is included in our sealing and repair pricing, not billed separately.
What happens when you call
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A real person answersNo phone trees - you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
BeforeAfterTrusted Brands We Service in Sterling
Our equipment roster includes professional-grade tools from trade-recognized manufacturers: Honeywell air cleaners and media filters, Aprilaire whole-home humidifiers and ventilation controls, and Abatement Technologies negative-air machines. We don’t invent performance claims beyond manufacturer specifications. These are brands Sterling homeowners can research independently, and we name them so you can. Parts for common Sterling HVAC configurations are stocked for fast turnaround on repair jobs.
Common Duct Repair & Sealing Problems We See in Sterling Homes
- Crushed flex runs at floor-joist pinch points. In Moorefield Village and Potomac Falls two-story colonials, we regularly find 6-inch flex duct compressed to 3-inch clearances where it was routed through tight framing. The blower motor short-cycles, rooms go stale, and energy bills climb.
- Disconnected collars at the air handler. Sterling’s temperature swings - from 20°F winter lows to 95°F summer highs - cause thermal expansion and contraction that loosens duct connections over decades. We find separated collars pulling unconditioned attic air directly into the return plenum, the box that distributes air from your HVAC unit.
- Micro-tears in aging flex combined with jet-exhaust particulate loading. Sterling’s position under Dulles arrival and departure corridors means outdoor-air intakes draw in measurably higher concentrations of fine particulate than homes a few miles west in Ashburn or north in Leesburg. This material embeds in micro-tears and builds up at low points where flex has sagged.
- Condensation and mold risk in uninsulated attic runs. The DC metro’s humid summers create persistent condensation on poorly insulated duct interiors. In Sterling’s unconditioned attics, this isn’t a maintenance issue - it’s a health issue when mold spores enter the airstream.
Pricing for Duct Repair & Sealing in Sterling, VA
We publish ranges because Haven Standard Clause 1 requires a written price before any work starts. Here is what duct repair and sealing actually costs in Sterling’s market:
| Service | Typical Range in Sterling |
|---|---|
| Spot duct sealing with mastic (single leaks, register boots) | $280-$450 |
| Flex duct repair / replacement (per run) | $340-$620 |
| Metal duct repair (accessible trunk section) | $380-$750 |
| Duct insulation (targeted sections) | $180-$320 |
| Full system duct insulation | $420-$680 |
| Comprehensive sealing + multiple flex repairs | $680-$1,200 |
Factors that move the price: attic accessibility, number of damaged runs, whether the air handler is in a closet or garage, and whether we discover disconnected trunk sections during camera inspection. We photograph everything before quoting. The price you sign is the price you pay.
Call (240) 771-1508 for a free written estimate - no obligation, no visit fee for standard scheduling.
We Also Serve Cities Near Sterling
Our crews work throughout Loudoun and Fairfax counties, including Herndon, Reston, Chantilly, and Leesburg. Each area has its own housing stock and ductwork patterns; Sterling’s Dulles-corridor particulate loading and 1987-2002 flex systems are distinct from what we find in newer Ashburn builds or older Leesburg homes. If you’re in one of these neighboring cities, we apply the same documented process and written pricing.
Serving Sterling, VA - Our Local Coverage Area
We’re based in the Sterling area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs - Duct Repair & Sealing in Sterling
Sterling’s housing stock was built primarily between 1987 and 2002 with builder-grade flexible duct rated for 15-25 years. Those systems are now 25-35 years old. Newer Loudoun County builds use updated materials and installation standards. In Sterling, we regularly find sagging flex, kinked runs, and disconnected collars that simply don’t occur in 2015+ construction. Call (240) 771-1508 for a camera inspection and written estimate.
It means your outdoor-air intake is drawing in fine particulate consistent with jet exhaust from Dulles International Airport’s active departure corridors. Prevailing westerly winds push this plume directly over Sterling’s Dulles-area subdivisions and Broad Run Farms. The material is not hazardous at typical concentrations, but it accumulates in duct systems and accelerates debris loading. We document this pattern in our photo records so you can see the difference between normal household dust and this distinctive deposit. Call (240) 771-1508 to schedule.
Proper duct sealing fixes the root cause when leaks are the problem. In a Sterling home with 20-30% air loss through trunk penetrations and register boots, sealing restores designed airflow to rooms that have gone stale for years. But sealing cannot fix a crushed flex run or a duct that was undersized from construction. Our camera inspection determines which problem you have before we quote. Call (240) 771-1508 for a written diagnosis.
We know after camera inspection. If the camera shows intact flex with surface debris, cleaning is appropriate. If it shows a crushed section, micro-tears, or a disconnected collar, cleaning alone will not restore airflow and may mask the underlying problem. In Sterling’s older systems, we find repair needs during roughly 40% of initial cleaning evaluations. We show you the photo before recommending anything. Call (240) 771-1508 to book an inspection.
It is a health issue once mold is established. The DC metro’s humid summers create condensation on poorly insulated duct interiors in Sterling’s unconditioned attics. That moisture, combined with organic debris, supports mold growth that releases spores into the airstream. We treat this with repair - fixing insulation gaps and sealing leaks that introduce moisture - not just cleaning. If we find active mold during inspection, we document it and explain the scope in writing before any work begins. Call (240) 771-1508 for a free evaluation.
Ready to see what’s actually inside your ductwork? Call CleanRun at (240) 771-1508 for a free written estimate. Every Sterling job includes a documented photo record, upfront pricing under Haven Standard Clause 1, and our 365-Day Done Right Promise. You’ll know what we found, what it costs to fix, and what your system looks like after - in writing, with photos, before we leave.
Written by Tomas Reyes, Owner at CleanRun Duct Repair & Cleaning, serving Sterling since 2013.