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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AfterTrusted Duct Repair & Sealing for Fairfax Homeowners
Duct repair and sealing in Fairfax typically costs $280-$890 depending on whether you’re addressing minor register leaks or replacing collapsed flex duct in an attic; see how much Duct Repair & Sealing costs for a detailed breakdown. Most residential jobs we complete in Fairfax County take 2-4 hours, and every one starts with a written price before any panel comes off. Call (571) 526-0015 and we’ll put our number next to any competitor’s written estimate, free.
We’ve been sealing and repairing ductwork in Fairfax since 2013 through our Duct Repair & Sealing in Fairfax. In that time we’ve documented the inside of 52,000+ homes, and we’ve learned what this specific market does to HVAC systems. The clay-heavy soils around Fairfax shift seasonally, which cracks slab foundations and stresses duct runs in crawl spaces. The humid summers here balloon flex duct until the inner liner separates from the insulation jacket. And the 1970s-1990s subdivisions off Route 50 and Braddock Road were built with galvanized metal duct that has now exceeded its corrosion-resistant lifespan. We see these patterns because we photograph every run before we touch it and after we leave. That photo record is part of your job file, not an upsell.
CleanRun is independently owned and operated under the Haven Standard. Tomas Reyes leads the operation, and our license number is published on this page, not buried in a footer. Every technician is background-checked, uniformed, and identified by name before arrival, per Haven Standard Clause 3: Verified Crews.
What Our Duct Repair & Sealing Service Includes
Duct Sealing
Duct sealing closes the gaps and seams where conditioned air escapes before reaching your rooms. In Fairfax, we most often find these leaks at plenum connections (the sheet-metal box where your furnace meets the duct trunk) and at register boots where the duct meets the wall or floor. Our crew pressurizes the system, identifies leaks with a smoke pencil or theatrical fog, then seals them with mastic or foil-backed tape rated for HVAC use. We document each sealed joint with before-and-after photos, and the written scope notes which seams were treated and which materials were applied.
Flex Duct Repair
Flex duct, the ribbed plastic tubing wrapped in fiberglass insulation, fails predictably in Fairfax’s climate. The attic temperatures here reach 140°F in July, degrading the plastic liner until it tears or pulls away from the collar. We’ve replaced entire flex runs in neighborhoods like Mantua and Kings Park West where squirrels have chewed through the insulation jacket. Our repair protocol includes cutting back to sound material, installing a new collar with a mechanical connection (not just tape), and supporting the run with proper straps to prevent sagging. Every repair is photographed and the photo record shows the new connection point and support spacing.
Metal Duct Repair
Galvanized steel ductwork in older Fairfax homes corrodes from the inside out, especially where condensation pools at low points in the trunk line. We cut out the damaged section, fabricate a replacement from matching gauge steel, and seal the joints with mastic and mesh reinforcement. In homes near Burke Lake or along the Accotink Creek watershed, we’ve found metal duct with pinhole corrosion severe enough to collapse sections of the trunk. Our crew carries sheet-metal tools and a brake on the truck, so we can fabricate custom fittings on site rather than waiting for ordered parts.
Duct Insulation
Uninsulated or degraded duct insulation wastes energy and creates condensation problems. In Fairfax’s humid climate, cold air moving through uninsulated supply ducts in a crawl space causes sweating that drips onto subflooring and promotes mold. We install new insulation with a vapor barrier, properly sealed at all seams, and we photograph the completed wrap to confirm full coverage. The R-value we specify depends on the duct location: R-6 for conditioned spaces, R-8 for attics and crawl spaces per current Virginia energy code.
Mastic Sealant
Mastic is a thick, water-based sealant that we brush or trowel onto duct joints. Unlike tape, which can peel or dry out, mastic remains flexible and forms a permanent bond. We apply it to all longitudinal seams on rectangular duct, to collar connections on round duct, and over the tape at plenum joints as a secondary seal. The work is messy and slow, which is why coupon operators skip it. We include it in our written scope when it’s needed, and the photo record shows the applied mastic before it skins over.
Air Leak Repair
Air leak repair addresses the larger breaches: disconnected ducts, missing end caps, or holes from contractor damage during renovations. In Fairfax’s active resale market, we’ve found new homeowners in neighborhoods like Fair Lakes and Fairfax Station discovering that a previous owner’s kitchen remodel severed a return duct behind the drywall. We locate the leak with a blower door and duct blaster when needed, repair the breach with appropriate materials, and verify the fix with a post-repair pressure test. The written report includes the pre- and post-repair leakage rates in CFM25.
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.
Brands We Service for Duct Repair & Sealing
We regularly repair and seal duct systems connected to Aprilaire whole-house dehumidifiers and air cleaners, common in Fairfax’s newer construction where builders spec them to manage summer humidity. We’ve serviced hundreds of Aprilaire units and stock their OEM collars and transition fittings, so we can seal the duct connections to their exact specifications without improvising.
Our equipment roster includes Abatement Technologies negative-air machines and Rotobrush mechanical agitation tools, which we use to clean duct runs before sealing them. Dirty ducts sealed with mastic trap debris against the sealant and eventually leak again. We clean first, then seal, and we document both steps. Whether you have Aprilaire, Abatement Technologies equipment on the job, or any other make of HVAC hardware, we can repair and seal the ductwork that connects to it.
BeforeAfterSigns You Need Duct Repair & Sealing Right Now
- Rooms that won’t heat or cool evenly. A bedroom that’s 10 degrees off from the thermostat usually has a disconnected or crushed duct run, not a failing HVAC unit. We’ve found flex duct collapsed behind attic insulation in Fairfax homes where the homeowner had already received three quotes for a new heat pump.
- Dust collecting rapidly around registers. Air leaking from a duct joint in an attic or crawl space creates negative pressure that pulls insulation fibers and particulate into the system. The dust you see at the register is often a symptom of leaks upstream, and it won’t stop until the leaks are sealed.
- Unexplained energy bills climbing year over year. The Department of Energy estimates that typical duct systems leak 20-30% of conditioned air. In Fairfax’s climate, that means your heat pump works overtime in August and your gas furnace runs longer in January. We’ve measured post-repair savings of 15-25% on heating and cooling costs after comprehensive sealing.
- Musty smells when the system runs. Leaky return ducts in crawl spaces draw in damp, moldy air and distribute it through the house. In homes near the flood-prone areas of Accotink Creek, we’ve found return leaks pulling air from standing water under the vapor barrier. Sealing the return eliminates the odor source.
- Visible duct damage in accessible areas. If you can see torn flex duct, rusted metal, or tape that’s peeled away from a joint, the condition behind walls and in attics is almost certainly worse. We photograph what we find so you can make a decision based on evidence, not speculation.
Our Duct Repair & Sealing Process - Step by Step
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Written estimate delivered before work starts. We inspect your duct system, identify the problems, and deliver a written price. Haven Standard Clause 1 requires this. No exceptions. The estimate specifies which runs will be repaired or sealed, which materials we’ll use, and what the final deliverables include.
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Pre-work photo documentation. Before touching a tool, we photograph the interior of every accessible duct run with a borescope camera. These images go into your job file and form the baseline for comparison. In Fairfax, we regularly show homeowners debris build-up, disconnected joints, or corrosion they didn’t know existed.
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Repair and sealing execution. Our crew performs the work specified in the written scope: sealing joints with mastic, replacing damaged flex or metal sections, insulating where needed. We use professional-grade equipment from Rotobrush, Nikro, Abatement Technologies, Honeywell, Aprilaire, and Guardsman, and we name the specific tools on your invoice.
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Post-work verification and photography. After completion, we re-photograph every run and perform pressure testing where applicable. The photo record shows the sealed joints, new materials, and clean duct interior. If we promised a leakage rate improvement, we measure it and record the number.
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Written job record delivered. You receive a complete file: the original estimate, before-and-after photos, any test results, and the 365-Day Done Right Promise in writing. If the work isn’t right, we make it right. This is a written guarantee, not a policy subject to manager approval.
How Much Does Duct Repair & Sealing Cost in Fairfax?
A typical duct sealing job in Fairfax runs $280-$550 for a single system with accessible ductwork and moderate leakage. Flex duct replacement in an attic or crawl space runs $340-$890 per run depending on length and access difficulty. Metal duct repair, which requires sheet-metal fabrication, typically falls between $450 and $1,200 depending on the extent of corrosion and the number of custom fittings needed. These are whole-system prices, not per-vent teaser rates that balloon once the truck arrives.
Several factors move the price. Attic access in Fairfax’s older split-levels and rambler-style homes off Little River Turnpike can require careful navigation around trusses and stored items. Crawl spaces with less than 18 inches of clearance slow the work and increase labor time. The extent of corrosion or damage determines whether we’re sealing joints or fabricating replacement sections. And the number of HVAC zones affects the total linear footage of duct to address.
We price by the scope of work, not by the vent count. A written estimate from CleanRun specifies exactly what we’ll do, what materials we’ll use, and what you’ll pay. No per-vent arithmetic, no surprise add-ons after we’re in your home. If you have a written estimate from another company, we’ll provide a free second opinion and put our number next to theirs. The estimate is free whether you hire us or not.
What’s included: the inspection, the written scope, all materials, labor, the documented photo record, and the 365-Day Done Right Promise. We also perform air duct cleaning as a separate or combined service if your ducts need cleaning before sealing.
Duct Repair & Sealing Near Fairfax - Our Service Area
We repair and seal ductwork throughout Fairfax County and into Loudoun, Prince William, and Arlington counties. Typical service reaches Reston and Centreville within our standard scheduling window, and we regularly work in Herndon, Arlington, Alexandria, Sterling, Manassas, Ashburn, and the closer Maryland suburbs including Rockville and Silver Spring. Homes in Washington, D.C. proper are evaluated case by case depending on parking and access constraints. Wherever we go, the same protocol applies: written price first, documented photo record included, Haven Standard Clause 1 in effect.
Serving Fairfax, VA - Our Local Coverage Area
We’re based in the Fairfax area and know this community well, and we also provide Reston Duct Repair & Sealing. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
Frequently Asked Questions - Duct Repair & Sealing in Fairfax
Duct repair and sealing fixes the physical structure of your duct system, while duct cleaning removes debris from inside it. Repair addresses leaks, disconnected joints, corrosion, and insulation damage; cleaning removes dust and particulate that has accumulated over time. We often recommend cleaning before sealing so that debris doesn’t get trapped behind new mastic seals, and we can bundle both services into a single written estimate.
Most residential duct repair and sealing jobs in Fairfax take 2-4 hours for a single system. Extensive flex duct replacement in a difficult attic can extend to a full day. We specify the estimated duration in your written scope so you can plan accordingly, and we don’t charge by the hour, so the price doesn’t change if the work runs long.
Typical costs range from $280 for basic sealing of accessible joints to $1,200 for extensive metal duct fabrication and replacement. The specific price depends on duct accessibility, the extent of damage, and the materials required. We deliver a written, itemized price before any work starts, and we offer free second opinions on any competitor’s written estimate. Call (571) 526-0015 for an exact quote on your system.
Yes. We regularly repair and seal ductwork connected to Aprilaire whole-house dehumidifiers, air cleaners, and ventilation systems, and we stock OEM fittings for proper transitions. We also work with duct systems connected to Honeywell, Guardsman, and all other major HVAC brands. The brand of your air handler or accessory doesn’t restrict our ability to repair the ductwork that connects to it.
We schedule repair work as promptly as our current job load allows, and all calls are answered by a live person who can assess urgency. Complete duct system failure in summer or winter is addressed with priority scheduling. We don’t charge emergency premiums, but we also don’t promise dispatch times we can’t meet. Call (571) 526-0015 to discuss your situation.
Every job is backed by the 365-Day Done Right Promise: if the work isn’t right, we make it right, backed in writing on every invoice. This applies to materials and workmanship. If a sealed joint fails within a year, we return and repair it at no charge. The photo record we provide documents the original condition and our work, so there’s no dispute about what was done.
Clear access to your HVAC equipment, attic hatch, and crawl space entrances. Remove stored items within 3 feet of the furnace or air handler. If you have pets, secure them in a separate room during the work. We don’t need you to clean or prepare the ductwork itself, that’s our job. After we finish, we leave the work area as we found it, with the addition of a documented photo record and written job file.
Schedule Your Duct Repair & Sealing Service in Fairfax Today
Call (571) 526-0015 to speak with a live person and schedule your free estimate. We’ll inspect your duct system, photograph what we find, and deliver a written price before any work starts. Every job includes a documented photo record and the 365-Day Done Right Promise in writing. No per-vent pricing, no bait-and-switch, no exceptions.
Written by Tomas Reyes, Owner at CleanRun Duct Repair & Cleaning, serving Fairfax since 2013.