Whole-home duct cleaning
Dryer vent cleaning
Camera inspection
Sanitizing & deodorizingWhole-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 North Merrick
If your ductwork is leaking in North Merrick, you’re losing conditioned air into crawlspaces, wall cavities, and abandoned plenums before it ever reaches your living room. We seal those leaks with mastic and Aeroseal, and we’ve been doing it long enough to know exactly where North Merrick’s homes hide them. Most whole-system sealing jobs in North Merrick run $1,800 to $3,400 depending on house size and how much access your duct runs give us. Call (516) 559-4917 and we’ll give you a written price before any work starts.

Key Takeaways
- Duct sealing in North Merrick typically costs $1,800 to $3,400 for a whole-home job; smaller targeted repairs start around $450.
- North Merrick’s oil-to-gas conversion history left ghost runs in many homes that pull humid crawlspace air into your supply ducts.
- We use camera inspection first, then mastic and Aeroseal. No fogging upsells, no bait pricing.
- Every job carries the 365-Day Done Right Promise: if the seal fails within a year, we come back at no charge.
- The price is written down before we touch a single duct. It does not move at the door.
Styles & brands we work with




Why Hollis Air Duct Hempstead Is North Merrick’s Preferred Duct Sealing Company
North Merrick keeps us busy on streets like Jerusalem Avenue, Camp Avenue, and the blocks around Merrick Avenue where split-levels and Capes sit on tight lots with shallow basements. Those homes share a problem: ducts retrofitted decades after the house was built, squeezed through spaces that were never meant to carry them. Roy Castellanos runs our crews, and he’s particular about the details: camera inspection before sealing, written pricing before work, and a site left cleaner than we found it. That’s the Duct Sealing standard we hold across every job.
We’re part of the Garrison Partners family and have been at this since 2004. Dispatch and scheduling for our North Merrick customers is coordinated from our New York City office, and the trucks roll out to Nassau County with the tools already loaded for the housing stock we know we’ll find. Background-checked, uniformed technicians; phones answered by a live person. That’s not marketing language. That’s how we run the schedule.
HVAC Duct Sealing in North Merrick
HVAC Duct Sealing in North Merrick means finding where conditioned air escapes before it reaches your vents, then closing those gaps with the right material for the location. In a split-level off Camp Avenue, that might mean sealing a disconnected return pulling damp air from a crawlspace. In a Cape on a side street, it might mean closing an abandoned warm-air plenum from an oil-to-gas conversion that’s been silently bypassing the system for twenty years. A full sealing job here runs $1,800 to $3,400. Targeted repairs start around $450.
Camera Inspection Before Any Sealant
We don’t guess where your leaks are. We send a camera through the duct runs and look for the joints, seams, and disconnections that are actually costing you money. In North Merrick’s shallow basements, a camera is the only way to see what’s happening behind a finished wall or under a crawlspace you can’t physically reach.
Aeroseal for Hard-to-Reach Runs
When duct runs snake through closets and low-clearance crawlspaces, we apply Aeroseal, a polymer mist that travels through the system and seals gaps from the inside. It’s the same approach commercial buildings use, and it reaches the spots a hand and a brush never will.
Duct Repair in North Merrick
Duct Repair in North Merrick usually means reconnecting sections that have sagged apart, patching rusted-out returns, or replacing a run that’s collapsed under its own weight in a humid crawlspace. The damp coastal air from South Oyster Bay accelerates rust and loosens tape. We see galvanized duct that looked fine five years ago now hanging open at the seams. Repair pricing runs $300 to $1,200 for most jobs; full section replacement in tight crawlspaces can push higher, and we’ll tell you the number in writing before we start.
Sealing Ghost Runs from Oil-to-Gas Conversions
Along Jerusalem Avenue and Camp Avenue, original oil-to-gas conversions left abandoned warm-air plenums that became bypasses. When we repair a system in North Merrick, we trace these ghost runs and seal them off at the trunk. Leaving them open pulls humid, salty air into the supply side and defeats the work you paid for. This is a North Merrick problem specifically, and generic duct cleaning pages don’t mention it.
Mastic and Mechanical Fasteners, Not Tape
We seal joints with mastic and mechanical fasteners because duct tape – the gray stuff everyone pictures – fails within a few years. It dries out, loses adhesion, and falls off. Mastic cures to a permanent, flexible seal that handles the temperature swings of a North Merrick attic in July and a crawlspace in January.

Trusted Brands We Service in North Merrick
Our trucks carry Rotobrush rotary brush systems and Nikro negative-air machines, and we stock filtration products from Honeywell, Aprilaire, and Guardsman for North Merrick customers. When your sealed system needs a new media cabinet or a HEPA-grade filter that actually fits, we have it on the truck. No waiting on a warehouse order. If your system has an Aprilaire unit or a Honeywell thermostat paired to the ductwork, we’ll make sure the sealing work plays nicely with the equipment.
See the difference
Before
After
Before
After
Before
AfterCommon Duct Sealing Problems We See in North Merrick Homes
- Ghost runs from old oil-to-gas conversions. Abandoned warm-air plenums act as bypasses, pulling crawlspace air into the supply side. We locate and seal them with camera inspection before doing anything else.
- Sagging duct joints in shallow Cape basements. Retrofitted ducts rarely have enough support. Joints sag open, and the humid air from South Oyster Bay condenses inside, feeding mold. We tighten, seal, and reinforce.
- Disconnected returns in low-clearance crawlspaces. Split-levels off Camp Avenue and Merrick Avenue often have central air shoehorned through spaces you can’t stand up in. Those connections loosen, and the system starts pulling damp, salty air directly into your home.
- Mold residue left by fogging sanitizers. Fogging treatments leave microbial material dead but present. Without source removal and proper sealing, regrowth returns within weeks in North Merrick’s damp duct runs. We clean first, then seal.
Pricing for Duct Sealing in North Merrick, NY
A typical whole-home duct sealing job in North Merrick runs $1,800 to $3,400. Smaller homes – a two-bedroom Cape – land on the lower end. Larger split-levels with multiple trunks and hard-to-reach crawlspace runs land on the higher end. Targeted repairs like sealing a single disconnected return start around $450. What moves the number is access: if we’re on our back in a 20-inch crawlspace for three hours, that’s different from a full-height basement. You get one flat price per system, written down before we start. No per-vent pricing, no upgrade pitch once the van is in your driveway. Call (516) 559-4917 for an exact quote – estimates are free.
We Also Serve Cities Near North Merrick
Our crews work throughout Nassau County and western Suffolk. We seal ducts in Hempstead, Flushing, Jamaica, and Massapequa regularly. If you’re just outside North Merrick, call us and we’ll tell you honestly whether we can get a truck to you without a long wait.
Serving North Merrick, NY - Our Local Coverage Area
We’re based in the North Merrick 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 North Merrick
No. Fogging kills surface spores but leaves the dead organic material behind, and in North Merrick’s humid duct runs that material acts as food for the next round of growth. Real mold control here means source removal – physically cleaning the duct walls – then sealing the leaks that keep bringing damp, salty air in. If someone offers you a fogging treatment as a standalone fix, walk away. Call (516) 559-4917 and we’ll show you what your ducts actually look like with a camera before recommending anything.
Because cleaning removes what’s already grown, but it doesn’t stop the humid air that caused it from entering through leaks. If a return duct is pulling damp, salty air from a crawlspace off Camp Avenue, the musty smell returns within weeks no matter how thoroughly the ducts were brushed. Sealing the breach with mastic is the only thing that stops the cycle. The smell is a symptom; the leak is the disease.
Salt air accelerates corrosion on galvanized duct and degrades standard foil tape adhesives faster than inland homes experience. That’s why we seal with mastic or Aeroseal rather than tape, and why we inspect fasteners and hangers on every North Merrick job. A seal that lasts fifteen years in a dry inland house might fail in eight here if the wrong material was used. We build for the salt.
In most cases, yes. A 1950s Cape with oil heat and retrofitted ducts often loses 20 to 30 percent of conditioned air into wall cavities and abandoned plenums before it reaches a register. Sealing those runs means the oil you’re buying heats your living room, not your crawlspace. The payback is faster in North Merrick than in towns with newer forced-air homes, because the starting efficiency is lower and the leak surface area is higher. Call (516) 559-4917 and we’ll give you a straight answer on whether your specific system is worth sealing.
Yes, but only as part of the broader fix. When ducts leak, they pull unfiltered air from crawlspaces and wall cavities – air that carries pollen from the oaks that line Jerusalem Avenue and the side streets around Merrick Avenue. Sealing those leaks forces the system to draw air through your filter, where the pollen actually gets caught. Pair the sealing with a proper filter media – we stock Honeywell, Aprilaire, and Guardsman products – and you’ll see a difference during the spring oak pollen season.
Get Your Duct Sealing Quote in North Merrick
Call (516) 559-4917 and we’ll schedule a camera inspection, give you a written price, and seal the leaks that are costing you money. We answer the phone. We show up inside the window. And if the seal fails within a year, we come back and make it right at no charge. That’s the 365-Day Done Right Promise, and it applies to every duct sealing job we do in North Merrick.
Written by Roy Castellanos, Owner at Hollis Air Duct Hempstead, serving North Merrick with camera inspection, mastic sealing, and Aeroseal since 2004.