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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Before
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Before
AfterTrusted Duct Repair & Sealing for Alexandria Homeowners
Duct repair and sealing in Alexandria typically costs $280-$890 depending on whether you’re sealing accessible joints or replacing collapsed flex runs, and most jobs are completed in a single visit. For a detailed breakdown, see our guide to how much Duct Repair & Sealing costs. CleanRun Air Duct Cleaning Alexandria has documented every duct repair with before-and-after photos since 2013, and we deliver a written price before any panel comes off - Haven Standard Clause 1. Call (240) 318-7712 for a free estimate with no obligation.
We’ve repaired ductwork in more than 52,000 homes, and the pattern in Alexandria Duct Repair & Sealing is consistent: homes built between 1985 and 2010, especially in neighborhoods like Del Ray, Rosemont, and the townhouse clusters near Eisenhower Avenue, have flex duct that has pulled from collars, metal duct with separated seams, or mastic that has dried and cracked after decades of humid summers and freeze-thaw cycles. The result is conditioned air bleeding into attics, crawl spaces, and wall cavities. Your HVAC runs longer. Your bills climb. The rooms farthest from the air handler never reach the thermostat setpoint.
We don’t sell duct repair with scare tactics. We show you what the camera found, put a written price in your hand, and let you decide. Every technician is background-checked and uniformed under Haven Standard Clause 3: Verified Crews, and every repair carries our 365-Day Done Right Promise in writing.
What Our Duct Repair & Sealing Service Includes
Duct Sealing
Duct sealing closes the gaps, cracks, and disconnected joints that leak conditioned air before it reaches your rooms. In Alexandria, we most often find leaks at the plenum - the central distribution box where your furnace or air handler connects to the main trunk line - and at register boots where the duct meets the wall or ceiling. CleanRun technicians pressurize the system and use a smoke pencil or theatrical fog to locate every leak, then seal with mastic or foil-backed tape rated for HVAC use. We photograph each location before and after, and the photo record is yours as part of the standard job deliverable.
Flex Duct Repair
Flex duct, the insulated flexible tubing common in Alexandria homes from the 1990s forward, collapses when support straps fail, gets crushed in tight attics, or pulls completely off its collar. When we find a collapsed flex run in a Del Ray bungalow or a Carlyle townhouse, we don’t patch it with tape and hope. We cut out the damaged section, install a new length of properly sized flex with metal collars and UV-resistant zip ties, and support it at 4-foot intervals per code. The camera shows the full circumference of the new connection before we close the access.
Metal Duct Repair
Galvanized steel ductwork, still common in pre-1985 Alexandria homes near Old Town and the Parker-Gray Historic District, separates at longitudinal seams and drive cleats as expansion and contraction work the joints over decades. We reseat the seams, apply a bead of water-based mastic, and reinforce with mesh tape for a permanent seal. Where rust has perforated the metal - we see this in crawl spaces with moisture issues, particularly near Four Mile Run - we section in new galvanized duct rather than covering the hole with patch tape that will fail in two seasons.
Duct Insulation
Uninsulated or degraded duct insulation in attics and crawl spaces costs you efficiency every minute the system runs. Alexandria’s summer design temperature of 92°F means attic ducts can reach 140°F, and without a proper vapor barrier, the insulation saturates with condensation. We install new foil-faced fiberglass insulation at R-6 minimum, sealed at all seams with matching foil tape, or replace flex duct whose insulation has compressed or torn. The improvement shows in the thermal image we include in your photo record.
Mastic Sealant
Mastic is a thick, water-based sealant that remains flexible after curing, making it the professional standard for duct joints that will expand, contract, and vibrate. We apply mastic with a brush or caulking gun to every joint, seam, and penetration in the duct system, then allow full cure time before pressurizing. Unlike duct tape, which dries and fails in 3-5 years, mastic lasts the life of the duct when applied correctly. We specify the mastic type and application thickness in your written scope of work.
Air Leak Repair
Air leaks are the gaps you can feel - the blast of attic air from a ceiling register in winter, the room that won’t cool because the duct is open in a wall cavity. We pressurize the system, measure total leakage with a duct blaster, then locate and repair each source. In Alexandria’s multi-story townhomes, we frequently find leaks where vertical chases connect floors, or where remodelers cut ducts and never sealed the openings. The repair is photographed, the leakage rate is retested, and the final number is recorded in your job file.
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
CleanRun technicians work with the equipment that moves air through your ducts, and we maintain familiarity with the major brands installed in Northern Virginia. We’ve serviced hundreds of Aprilaire zoning systems and their associated dampers, and we stock replacement dampers and actuator motors for common configurations. Abatement Technologies negative-air machines and HEPA filtration equipment are part of our standard inventory - we use their PREDATOR series on jobs where containment matters, and we can service or replace Abatement components integrated into your duct system.
We also work with Guardsman access doors and panels, which we install when creating service openings in ductwork that lacks them, and Rotobrush brush-and-vac systems for mechanical cleaning of duct runs before sealing. Whether you have Aprilaire, Abatement Technologies, Guardsman, Rotobrush, or any other make, we can assess the condition of your ductwork, identify the leaks or damage, and deliver a written repair scope with a fixed price.
BeforeAfterSigns You Need Duct Repair & Sealing Right Now
- Uneven temperatures from room to room. When the master bedroom is 8 degrees warmer than the living room in July, the duct delivering air to that room is likely leaking, blocked, or disconnected. Your thermostat only measures one location, so the system runs until that spot is satisfied while other rooms suffer.
- Dust that returns within days of cleaning. If you’re wiping surfaces clean on Monday and finding a fresh layer by Wednesday, your return ducts may be pulling attic or crawl space air through gaps. That dust isn’t normal household debris - it’s insulation particles, rodent droppings, and soil from spaces that should never connect to your breathing air.
- Utility bills that climbed without rate increases. A 20% jump in your Dominion Energy bill with no change in rates or usage habits often traces to duct leakage. The system runs 30-50% longer to deliver the same comfort, and every extra minute is money.
- Whistling or rushing air sounds from walls or ceilings. High-velocity air escaping through a gap in ductwork creates turbulence you can hear. The sound localizes near the leak, and it’s a reliable indicator that pressure is being lost before reaching the register.
- Musty or chemical odors when the system starts. If the first 30 seconds of airflow smell like a crawl space, attic, or garage, the return side is pulling from those zones through a breach. This isn’t a filter problem - it’s a duct integrity problem, and it affects indoor air quality directly.
Our Duct Repair & Sealing Process - Step by Step
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System inspection and pressure test. We start with a visual assessment of accessible ductwork and a pressure test to quantify total leakage. The duct blaster fan attaches to your air handler, pressurizes the system to 25 Pascals, and measures cubic feet per minute of leakage. A typical Alexandria home of 2,000 square feet should leak less than 10% of total airflow; we regularly measure 25-40% in homes that haven’t been sealed.
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Leak location with smoke or theatrical fog. With the system pressurized, we inject non-toxic fog or use a smoke pencil at every joint, seam, and penetration. The visible airflow shows exactly where your conditioned air is escaping. We photograph each location for the before record.
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Written scope and fixed price delivered. Before any repair begins, you receive a written document listing every leak found, the repair method for each, materials to be used, and the total price. Haven Standard Clause 1 requires this; there is no verbal estimate, no “call for pricing,” no surprise add-ons once work starts. You approve in writing or we leave - no charge for the diagnostic.
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Repair and sealing with documented photo record. Our technicians execute the scope: mastic application, flex replacement, metal reseaming, insulation replacement, or access panel installation as specified. Every repair is photographed before and after, with timestamps. The photo record is uploaded to your job file and delivered as part of the standard closing package.
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Post-repair pressure test and verification. We retest with the duct blaster to confirm leakage reduction. The final number is recorded on your invoice, and the 365-Day Done Right Promise is activated in writing. If any sealed joint fails within that year, we return and correct it at no charge.
How Much Does Duct Repair & Sealing Cost in Alexandria?
A typical duct sealing job in Alexandria runs $280-$550 for a single system with accessible ductwork and moderate leakage. Flex duct replacement, when one or two runs have collapsed or pulled free, ranges $340-$680 depending on length and attic accessibility. Metal duct repair with seam resealing and reinforcement falls at $320-$620. Full duct insulation replacement in an attic or crawl space runs $480-$890 for a complete system. These are whole-system prices, not per-vent teaser rates that balloon once the truck arrives.
Several factors move the price within these ranges. Attic accessibility matters: a truss attic with 18 inches of blown insulation takes longer to navigate than a basement with exposed joists. The extent of leakage affects material volume - a system with 15 separated joints needs more mastic and labor than one with 3. Duct material type determines repair method; metal takes longer to reseam than flex takes to replace. And the location of damage matters - a register boot in a second-floor ceiling requires more access work than a basement plenum joint.
What affects price most is whether you’re comparing honest whole-system quotes or the industry’s common bait pattern: a $79 “duct inspection” that becomes a $2,400 pressure sale once the technician is in your home. CleanRun does not operate this way. Our price is written, fixed, and delivered before work starts. If you have a competitor’s written estimate, we provide a Free Second Opinion - our number next to theirs, no obligation.
Every estimate includes the diagnostic pressure test, all materials, labor, the documented photo record, and the 365-Day Done Right Promise. There are no per-vent surcharges, no equipment fees, no after-hours premiums. Call (240) 318-7712 for your written estimate.
Duct Repair & Sealing Near Alexandria - Our Service Area
CleanRun serves Alexandria and the full Northern Virginia corridor. We regularly repair ductwork in Arlington, where the housing stock of garden apartments and converted row houses presents unique access challenges, and in Springfield, where 1970s-1990s split-levels often have flex duct at the end of its service life. Our technicians also cover Falls Church, Washington, McLean, Tysons Corner, Vienna, Bethesda, Fairfax, Silver Spring, Reston, and the full metro core. Most Alexandria addresses receive next-available scheduling; Arlington and Springfield typically book within 48 hours. The home page lists current availability by zone.
Serving Alexandria, VA - Our Local Coverage Area
We’re based in the Alexandria area and know this community well. 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 Alexandria
Duct repair and sealing fixes the gaps, disconnections, and damage in your HVAC distribution system that leak conditioned air into spaces you don’t occupy. You need it if your pressure test shows leakage above 10% of total airflow, if you have rooms that won’t maintain temperature, or if your energy bills have climbed without explanation. Most Alexandria homes built before 2010 have measurable duct leakage; whether repair is cost-effective depends on the severity, which we determine with a free diagnostic.
A typical sealing job takes 3-5 hours; flex duct replacement adds 1-2 hours per run. We schedule a full day block for every job so technicians aren’t rushing to the next appointment. You’ll know the expected duration before we start - it’s written on your scope sheet. Call (240) 318-7712 to check next available dates.
Duct sealing runs $280-$550, flex duct repair $340-$680, metal duct repair $320-$620, and full insulation replacement $480-$890 for a typical single-system home. The exact price depends on accessibility, leakage extent, and materials needed. We deliver a written fixed price before any work begins - no exceptions. Call (240) 318-7712 for your specific estimate.
Yes. We regularly repair ductwork connected to Aprilaire zoning systems, service Abatement Technologies filtration and negative-air components, and install Guardsman access panels. Our technicians carry common parts for these brands and can source OEM components within 24 hours for less common configurations. The brand of your air handler or filtration equipment doesn’t restrict our ability to repair the ductwork itself.
We answer calls live 24 hours a day and schedule urgent repairs for collapsed ducts or complete disconnections that have left a home without heating or cooling. We do not charge after-hours premiums - the written price is the written price regardless of when the work is performed. For true emergencies where the HVAC system is inoperable, we prioritize same-day or next-day scheduling.
Every repair is backed by our 365-Day Done Right Promise: if any sealed joint fails, any replaced flex run collapses, or any repair doesn’t perform as specified, we return and correct it at no charge. This is a written guarantee, not a policy subject to manager approval. The promise activates the moment you pay your invoice and remains in force for 365 days.
Clear access to your air handler, attic hatch, crawl space entrance, and any ceiling registers in rooms with known problems. If you have pets, secure them in a separate room - our technicians need to move between the attic, crawl space, and living areas repeatedly. You don’t need to clean or move furniture beyond creating a 3-foot workspace. We’ll handle the rest, including drop cloths and post-job cleanup.
Schedule Your Duct Repair & Sealing Service in Alexandria Today
Call (240) 318-7712 to speak with a live person and schedule your free estimate. We’ll pressure-test your system, show you every leak the camera found, and deliver a written fixed price before any work begins. Every job includes the documented photo record and the 365-Day Done Right Promise. No coupons, no surprises, no vacuum noise.
Written by Tomas Reyes, Owner at CleanRun Air Duct Cleaning Alexandria, serving Alexandria, Duct Repair & Sealing in Arlington, Springfield, and Northern Virginia since 2013.