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.
Fast, Reliable Duct Sealing Across Flourtown
Duct sealing in Flourtown typically costs $450 – $1,200 for a whole-house seal, depending on system accessibility and the condition of your existing ductwork. Most jobs take four to six hours and are scheduled within a week of your call. We’re Hollis Air Duct Cleaning, and our Duct Sealing crews serve Flourtown from our Philadelphia dispatch office, carrying the same Rotobrush and Nikro equipment we use on commercial jobs throughout Montgomery County. If you’re in a pre-war stone home off Bethlehem Pike or a mid-century ranch near the Springfield Township line, we’ve likely sealed ductwork in a house just like yours. Call (361) 326-5060 for a free written estimate.
Why Hollis Air Duct Cleaning Is Flourtown’s Preferred Duct Sealing Company
We’ve been in business since 2004 as part of the Garrison Partners family, and our reputation in Flourtown is built on showing up inside the quoted window and pricing in writing before any work starts. Our technicians are background-checked, uniformed, and trained to The Garrison Code, which means they arrive squared away, explain what they’re doing in plain terms, and leave the site clean. Calls are answered by a live person 24 hours a day, seven days a week, so you’re never stuck in a voicemail loop when you need to schedule or ask a follow-up question.
What sets us apart in Flourtown specifically is our familiarity with the housing stock here. We’ve sealed ducts in century-old fieldstone homes where original galvanized runs share chases with radon mitigation systems, and we’ve worked beneath flagstone patios near Bethlehem Pike and Paper Mill Road where exterior access would crack irreplaceable stone. That kind of local knowledge prevents costly mistakes. Every repair we make is backed by our 365-Day Done Right Promise: if the seal fails within a year, we come back and make it right at no charge, including a free second visit.
Duct Insulation in Flourtown
Duct Insulation in Flourtown addresses a problem most homeowners don’t know they have: conditioned air bleeding into unconditioned spaces before it ever reaches your vents. In Flourtown’s pre-1940 homes, especially the stone and stucco properties along the Bethlehem Pike corridor, ducts often run through former springhouse crawl spaces or root cellars that stay damp year-round. Without proper insulation, you’re paying to heat or cool those spaces instead of your living areas. A typical duct insulation job in Flourtown runs $600 – $1,400, with older homes at the higher end due to irregular chase configurations and the need to work around asbestos-wrapped joints.
When Insulation Beats Sealing Alone
Sometimes the duct itself is intact but bleeding temperature through thin metal walls. In Flourtown’s humid continental climate, that temperature differential creates condensation, which breeds mold in basement runs. We see this most often in homes near the Wissahickon Valley where summer humidity spikes above 80 percent. Insulation with a proper vapor barrier solves both problems at once.
Materials We Use
Our crews carry fiberglass wrap with foil backing and closed-cell foam sleeves from Guardsman and Abatement Technologies, selected for your specific application. We don’t guess at R-value; we measure the temperature drop across your duct runs and specify insulation thickness to match. The price is written down before we open a single chase.
HVAC Duct Sealing in Flourtown
HVAC Duct Sealing in Flourtown closes the gaps, cracks, and disconnected joints that leak conditioned air into walls, attics, and crawl spaces. In a typical Flourtown home with original ductwork, we measure 20 – 35 percent air loss before sealing, which means your furnace or air conditioner works a third harder than necessary. Our sealing process uses mastic compound and fiberglass mesh for permanent joints, plus aerosol sealant for inaccessible runs, applied with Nikro negative-air equipment to contain overspray. Most HVAC duct sealing jobs in Flourtown fall between $450 and $1,200, with whole-system seals on larger stone homes reaching the top of that range.
Access Challenges in Older Homes
Flourtown’s fieldstone construction often hides duct runs inside walls with no access panels. When we encounter this near Paper Mill Road or along the original farmland plots, we cut interior basement access rather than risk exterior stone. Our technicians carry matching patching materials and leave the work area cleaner than we found it.
Testing Before and After
We verify every seal with a duct blaster test, measuring leakage in CFM at 25 Pascals. You get the before and after numbers in writing, plus photos of the sealed joints. No guesswork, no “trust us, it’s better.” The data is yours to keep.
Trusted Brands We Service in Flourtown
Our trucks stock sealing mastics, insulation wraps, and filtration upgrades from Aprilaire, Abatement Technologies, and Guardsman, the same brands commercial HVAC contractors specify for hospitals and schools. For Flourtown homeowners, that means no waiting on special orders when we find a failed joint or missing insulation during your seal. We also carry Honeywell and Aprilaire filtration products to upgrade your system while we’re in the ductwork, often installed the same day. If your home has a Rotobrush-compatible access port from a previous cleaning, we can integrate our sealing work without additional cutting. Parts availability matters in older homes where every day of delay means another day of wasted energy.
Common Duct Sealing Problems We See in Flourtown Homes
- Galvanized ductwork with rusted seams. In pre-1940 Flourtown homes, original metal ducts have had a century of humid summers and freeze-thaw winters. The seams corrode from the inside out, creating pinhole leaks that aerosol sealant can’t fully address. We cut out failed sections and splice in new with mastic-wrapped collars.
- Asbestos-wrapped joints disturbed by previous work. Many Flourtown basements still have asbestos cloth on duct joints. If a previous contractor broke the wrap to access a fitting, those fibers now circulate and the seal is compromised. We identify this before work starts and coordinate proper containment with certified remediation partners.
- Ducts drawing from damp crawl spaces. Former farmland properties converted in the early 1900s often have supply runs pulling air from spaces that were never meant to be conditioned. Sealing the duct helps, but without addressing the moisture source, you’re pressurizing mold into the living space. We flag this during inspection and recommend Air Duct Cleaning in Flourtown if microbial growth is present.
- Disconnected flex duct in ranch additions. The 1950s-60s ranches near the Springfield Township line often have DIY basement renovations where flex duct was shoved onto metal collars without proper clamps. These blow apart under pressure and leak into joist bays. We secure with permanent mechanical fasteners, not tape that dries out in three years.
Pricing for Duct Sealing in Flourtown, PA
A typical whole-house duct seal in Flourtown runs $450 – $1,200. Single-zone repairs on accessible basement trunk lines start around $350. Duct insulation added to sealing work adds $600 – $1,400 depending on linear feet and chase accessibility. Homes with original fieldstone foundations, radon mitigation systems sharing duct chases, or flagstone patio access restrictions fall toward the higher end due to labor time.
What drives cost: number of supply and return runs, accessibility (crawl space versus full basement), condition of existing joints, and whether asbestos abatement is needed before we can safely seal. We don’t quote per-vent or offer teaser coupons that balloon at the door. You get one flat price per system, agreed in writing before any work starts, with no surprise charges for “extra material” or “unforeseen complications.” Free estimates include a full inspection, duct blaster leakage test, and written quote. Call (361) 326-5060 to schedule.
We Also Serve Cities Near Flourtown
Our crews regularly travel from the Philadelphia office to Duct Sealing in Flourtown and surrounding communities. We also handle Dryer Vent Cleaning in Flourtown for homeowners who want their full ventilation system checked in one visit. Nearby cities we serve include Oreland, Fort Washington, Glenside, and Plymouth Meeting, with the same written pricing and 365-Day Done Right Promise on every job.
Serving Flourtown, PA - Our Local Coverage Area
We’re based in the Flourtown 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 About Duct Sealing in Flourtown
We typically schedule duct sealing in Flourtown within five to seven business days of your call, sometimes sooner depending on season. Spring and fall are busiest when HVAC systems switch over, so calling a few weeks ahead helps secure your preferred date. Call (361) 326-5060 to check current availability.
Yes, we seal ducts throughout Flourtown including the Bethlehem Pike corridor, properties near Paper Mill Road, and the ranch neighborhoods near the Springfield Township line. Our technicians know the access challenges specific to each area, from interior basement cuts for flagstone patio homes to crawl space protocols for former farmland properties.
We don’t classify duct sealing as an emergency service, but our phones are answered by a live person 24 hours a day, seven days a week. If you have a complete duct failure in extreme weather, we’ll prioritize scheduling and can often arrange next-day inspection. For true HVAC emergencies, we recommend contacting your heating or cooling contractor first, then calling us for the sealing repair.
Flourtown pricing is comparable to Oreland and Glenside, though pre-war stone homes here often require more labor than post-war construction in Plymouth Meeting. The $450 – $1,200 range we quote reflects actual job conditions, not zip code. Your written estimate is based on your specific home after inspection, not a generic city surcharge.
Every duct seal is covered by our 365-Day Done Right Promise in writing. If any sealed joint fails within one year of completion, Hollis returns and repairs it at no charge, including a free second visit. This applies to all Flourtown jobs and is backed by the Garrison Partners family track record since 2004, not a third-party warranty company.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving Flourtown and Montgomery County since 2004.




Before
After
Before
After
Before
After