Duct Repair & Sealing Cost - Tested First, Written Price Second

Every visit starts with

Whole-system duct and dryer vent check with before-and-after photos - you see exactly what came out of your vents

Worth knowing

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 & after – our own jobs

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How Much Does Duct Repair & Sealing Cost in Rockville?

Our Duct Repair & Sealing services in Rockville, MD typically cost between $350 and $1,200 for a standard single-family home, with most jobs landing in the $500-$850 range. Aerosol-based sealing (Aeroseal) runs higher, from $1,400 to $2,500, depending on duct volume and leakage rate. Most Rockville homeowners get a final written price within 24 hours of their inspection – no range, no estimate range, a number.

Duct Repair & Sealing Cost Breakdown (2026)

The table below reflects real job data from Rockville and the surrounding Montgomery County market. These are not national averages pulled from an aggregator – they are the price ranges CleanRun has written on actual invoices in this area since 2013. Your written price comes before any work starts; that is Haven Standard Clause 1, and it does not have exceptions.

What Pushes the Price Higher

Two things inflate duct repair costs faster than anything else in Rockville: access and volume. A split-level home in East Rockville or Twinbrook with ductwork routed through a finished ceiling means a technician is working through small access panels or, in some cases, recommending Aeroseal precisely because manual access is not feasible. Add in a house with 18 or more duct runs – not unusual in the larger colonials near Fallsgrove – and the labor hours stack up before a single piece of mastic is applied.

Older flex duct in homes built between the late 1970s and mid-1990s is a separate cost driver. The inner liner degrades, collapses at sag points, and in some cases has to be replaced entirely rather than sealed. When a camera inspection shows 4 or 5 sections in that condition, replacement cost displaces sealing cost on the invoice.

Pest activity is more common in Rockville than most homeowners expect – particularly in homes backing to Cabin John Regional Park or the Rock Creek watershed corridor. Rodents breach flex duct and sheet metal alike, and those penetrations need to be patched before any sealing is effective. That adds both material cost and, sometimes, coordination with a pest management company before CleanRun can close out the job.

What Brings the Price Down

Newer construction in Rockville – say, townhomes built in the 2010s around King Farm or Fallsgrove – often has more accessible ductwork, less degradation, and fewer penetrations from retrofits. Sealing a house like that is straightforward work: accessible joints, clean metal surfaces, and a leakage profile that responds well to mastic without additional patching. Jobs in that category routinely fall at the lower end of the $450-$600 range for a whole-house seal.

Combining duct cleaning with duct sealing in a single visit also reduces the overall cost compared to scheduling them separately. The ductwork has to be accessed either way; a combined visit eliminates duplicate travel, setup, and access time. If you have a competitor’s written estimate, CleanRun will put its own number next to it in writing before any work starts – that is the Free Second Opinion, available at no cost, no obligation.

What Affects Duct Repair & Sealing Pricing in Rockville

• Home size and duct count: A 1,500 sq ft Twinbrook rancher with 8 supply runs costs less to seal than a 3,500 sq ft Fallsgrove colonial with 20 runs and a return plenum in the attic. Pricing scales with how many duct sections, joints, and boots need to be addressed – not with a flat per-square-foot formula.
• Duct material and age: Rigid sheet metal holds mastic better and longer than deteriorated flex duct. Rockville homes built before 1990 frequently have a mix of both, and the flex sections often need replacement rather than sealing – which changes the cost profile on the spot once the camera is inside.
• Access difficulty: Ductwork in conditioned, finished basement spaces or open utility rooms is straightforward to reach. Ducts routed above drywall ceilings, inside knee walls, or through attic spaces with blown-in insulation take longer to access, document, and seal. In some East Rockville and mid-century West End homes, access limitations are the single biggest cost factor.
• Leakage rate and location: A duct system leaking 15% of conditioned air has more joints and breaches to address than one leaking 8%. A pre-repair duct blaster test quantifies where you are starting; that number shapes how much material and labor the repair will require. Homes near Rock Creek that have experienced water intrusion often show leakage at seams that have shifted with seasonal moisture movement.
• Sealing method required: Manual mastic and foil tape work well on accessible leaks at joints and seams. Inaccessible leaks – inside finished walls, above glued drywall, or at concealed elbows – cannot be reached by hand. Aeroseal addresses those by injecting aerosolized sealant under pressure from inside the duct itself, which is why the price difference between manual sealing and Aeroseal is significant. It is not the same service at a different price point; it solves a different problem.
• Condition of duct lining and insulation: Ducts in unconditioned attics in Rockville are supposed to be insulated to R-6 or better under current Maryland energy code. When that insulation is damaged, separated, or missing – common in homes where prior HVAC work was done without replacing disturbed insulation – restoring it is part of a proper repair scope. If a technician quotes only sealing on an attic duct with missing insulation, the energy performance gain will be partly offset by conductive loss. CleanRun scopes what is actually in front of the camera.

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How to Save on Duct Repair & Sealing in Rockville

Start With a Diagnostic, Not a Repair Assumption

The most expensive duct repair jobs CleanRun encounters in Rockville are the ones where a previous contractor sealed the wrong things. Mastic applied over a return plenum seam that was not the primary leak source does not fix a duct system losing 25% of its air through a disconnected supply trunk in the attic. Before agreeing to any repair scope, get a duct leakage test – a duct blaster pressurizes the system and measures total leakage so you know whether you have a $500 problem or a $2,000 problem. That test runs $200-$400 as a standalone; it is often credited toward the repair if you proceed with the same contractor.

Combine Services in a Single Visit

If your ductwork needs both cleaning and sealing – and the camera inspection will tell you whether it does – schedule both in one visit. The ductwork is already open, the crew is already there, and the access work is not duplicated. This can save $150-$300 compared to two separate appointments, and it means the photo record documents the inside of the system before and after both services on a single job record. That documentation matters more than most homeowners realize when it comes time to sell – a buyer’s home inspector who asks about HVAC system condition can be handed a before-and-after photo record rather than a vague service receipt.

Get a Written Second Opinion Before You Commit

If you have already received a written estimate from another contractor, CleanRun will review it and provide a written number in response – line item by line item. This is the Free Second Opinion, and it exists because CleanRun’s pricing is written down and defensible. Call (240) 255-4519 to set that up; you bring the estimate, we put our number next to it.

Understand What the $79 Coupon Is Not Buying You

Rockville homeowners see a lot of direct mail for whole-house duct cleaning or sealing at prices that do not cover the labor to do the work correctly. Those services typically involve a shop-vac-grade machine, no camera inspection, and no documentation of what was found or what was done. Duct sealing priced below $200 for a whole house is not duct sealing – it is tape on visible joints, applied with no knowledge of where the actual leakage is. The cost of repeating that work with a contractor who starts from a diagnostic is higher than starting with a diagnostic the first time.

Check Maryland Energy Programs for Rebates

Maryland’s EmPOWER program and BGE’s Smart Energy Savers program have periodically offered rebates for duct sealing work that meets a post-repair leakage threshold – typically verified by a duct blaster test. Eligibility and rebate amounts change; as of early 2026, BGE customers in Rockville should check bge.com/saveenergy directly for current incentives. A documented post-repair leakage test, which CleanRun includes in the Aeroseal job scope, is the record you need to file for those rebates.

FAQs – Duct Repair & Sealing Cost in Rockville

How much does duct sealing cost in Rockville, MD?

Manual duct sealing in Rockville costs $450-$950 for a whole-house job on a typical 2,000-3,200 sq ft home. Individual duct run repairs run $60-$250 per section depending on method and material. Aeroseal, which addresses inaccessible leaks from inside the duct under pressure, runs $1,400-$2,500. Every CleanRun job starts with a written price before work begins – call (240) 255-4519 and we will put a number on paper before the truck leaves the driveway.

Is it worth sealing ducts in an older Rockville home?

In most cases, yes. Homes built before 1995 in Rockville – particularly in Twinbrook, Hungerford, and mid-century sections of West End – have duct systems that were assembled before modern sealing standards existed. A duct system leaking 20-30% of conditioned air is adding $200-$400 per year to energy costs in a climate with Maryland’s hot-humid summers and cold winters. Sealing that system to a 10% or lower leakage rate typically pays back the repair cost in 3-5 years on energy savings alone, before accounting for comfort improvement and HVAC equipment load reduction. A duct blaster test before and after quantifies exactly what you gained.

How long does duct sealing last in a Maryland climate?

Mastic sealant on clean, dry metal surfaces lasts 20-30 years under normal conditions. Foil-backed tape, when applied correctly to clean metal, is rated for 15-20 years. The variable in Maryland is humidity: Rockville sits in a mixed-humid climate zone (IECC Zone 4A), and ductwork in unconditioned attics or crawl spaces cycles through significant temperature and humidity swings. Mastic handles that better than tape in those locations. Aeroseal’s polymer-based sealant is rated for the life of the duct system. CleanRun documents the condition of every duct run before sealing begins – that photo record is your baseline if a seam opens five years from now and you need to assess whether it was covered in the original scope.

Can duct sealing be done in one day in Rockville?

Manual duct sealing on a standard single-family home in Rockville is typically completed in 4-8 hours, same day. Aeroseal jobs run 5-7 hours including setup, the injection process, and post-test verification. Homes with difficult access – finished attics, specific mid-century configurations in East Rockville, or ductwork that requires partial demolition and re-installation – can extend into a second day. The written scope delivered before work starts will specify the estimated time; if there is any possibility of a second-day return, that is noted in the scope before you sign anything.

What is the difference between duct repair and duct sealing?

Duct repair addresses structural failures: a disconnected flex duct section, a separated plenum connection, a breach from pest activity, or a collapsed inner liner that has blocked airflow. Those require physical intervention – replacement material, sheet metal patches, or reconnection hardware. Duct sealing addresses leakage at joints and seams that are intact but not airtight: mastic or tape applied to those points reduces the conditioned air escaping into unconditioned space. Many jobs require both – a camera inspection finds the structural failures that need repair, and a leakage test afterward quantifies what sealing remains to be done. Pricing for the two scopes is separate and itemized; you see both numbers before work begins. For a full explanation of what each service covers, see our Duct Repair & Sealing in Rockville page.

What CleanRun’s Written Price Actually Includes

This question comes up more than it should, because “duct sealing” means different things depending on who is writing the invoice. When CleanRun delivers a written price for duct repair and sealing in Rockville, it includes a camera inspection of every accessible duct run before work begins, a documented before-and-after photo record of every run as a standard job deliverable, all mastic, foil tape, or flex duct material used in the scope, labor for access, sealing, and restoration of any access points opened during the job, and a written scope that identifies what was found, what was done, and what the post-repair condition is. The 365-Day Done Right Promise is on every invoice in writing – if something covered in the scope is not right within a year, CleanRun makes it right. That is not a policy subject to manager discretion; it is a written term on the job record.

Haven Standard Clause 1 means the written price is the price. There is no adjusted invoice at the end of the day based on what the crew found inside the walls. If the camera finds something outside the original scope – a collapsed flex section that was not visible from the register, for example – the technician stops, photographs it, explains it, and writes a separate line item for your approval before proceeding. You are never looking at a surprise charge at the end of a job.

CleanRun vs. the $79 Coupon Contractor: What the Camera Shows

In West End Rockville last spring, a homeowner called CleanRun after a low-price contractor had completed a “whole-house duct sealing” the previous fall. The homeowner’s energy bills had not changed. The camera showed tape applied to the two supply boots visible from the utility room – and nothing else. The return plenum had a 6-inch gap at the top-plate penetration. Two flex duct sections in the attic had separated at their collars. Those locations were not touched because the previous contractor had not used a camera. The documented photo record CleanRun delivered after its own repair showed exactly what was found and what was done at each location. That record also went to the homeowner’s HVAC technician as part of a broader system efficiency review.

This is not an isolated case. It is the reason CleanRun photographs the inside of every duct run before saying anything about what needs to happen. The photo is the argument. Tomas Reyes built the documented photo record into CleanRun’s standard process in 2013, and it has not changed since – not because it is good marketing, but because it is the only way to hold repair work accountable after the truck leaves.

If you are comparing CleanRun to another contractor and the other contractor has not offered a before-and-after photo record, a written price before work starts, and a written guarantee tied to the specific work performed, those are not omissions you should overlook. Ask for them in writing. Any contractor doing legitimate work can produce all three without hesitation.

Key Takeaways

• Manual duct sealing in Rockville runs $450-$950 for most whole-house jobs; Aeroseal runs $1,400-$2,500.
• Individual run repairs cost $60-$320 depending on method and damage type.
• A duct leakage test ($200-$400) identifies where the real losses are before any sealing begins – skip this and you risk sealing the wrong joints.
• Rockville’s mixed-humid climate and the age profile of its housing stock (many homes built 1975-1995) make duct leakage both more common and more costly than in newer housing markets.
• Every CleanRun job includes a written price before work starts, a documented photo record when the crew leaves, and the 365-Day Done Right Promise in writing.
• Combining duct cleaning and sealing in one visit saves $150-$300 compared to scheduling them separately.
• BGE’s Smart Energy Savers program may offer rebates for qualifying duct sealing work – a post-repair leakage test is the documentation you need to file.

Ready for a Written Price?

CleanRun Air Duct Cleaning Rockville serves Rockville and Montgomery County with written upfront pricing on every job – no call-for-a-quote, no estimate ranges. Tomas Reyes and the CleanRun team have documented the inside of ductwork in more than 52,000 homes since 2013, and every Rockville job includes a before-and-after photo record as a standard deliverable. If you have a competitor’s written estimate, bring it: CleanRun will put its own number next to it in writing before any work starts.

Call (240) 255-4519 to schedule a free estimate. A live person answers every call. You will have a written price before the crew touches anything.

For a full explanation of the service itself – what gets repaired, what gets sealed, and why the distinction matters – visit our Duct Repair & Sealing in Rockville page. More information on CleanRun’s full range of services is available on our home page.

Written by Tomas Reyes, Owner at CleanRun Air Duct Cleaning Rockville, serving Rockville, MD since 2013.

Pricing reflects the Rockville market as of 2026. CleanRun Air Duct Cleaning Rockville offers free estimates – call (240) 255-4519.