Duct Sealing in Annapolis - Tested First, Written Price Second

Fast, Reliable Duct Sealing Across Annapolis

Duct sealing in Annapolis typically runs $800 – $2,400 for a whole-home system, depending on whether we’re working with standard suburban ductwork or the retrofitted runs common in the Historic District. Our crews serve Annapolis from our Baltimore office, and we schedule most sealing jobs within a few business days. Call (361) 326-5060 for a written estimate before any work starts.

Call (361) 326-5060

We’ve worked in Annapolis long enough to know the difference between a Broadneck ranch with galvanized duct in a dry attic and a Maryland Avenue Colonial with flex duct snaking through a tidewater-damp crawlspace. That local knowledge changes how we approach the job, what equipment we bring, and whether we need to address moisture before we seal. Our Duct Sealing team treats every house on its own terms, not with a one-size-fits-all approach.

Why Hollis Air Duct Cleaning Is Annapolis’s Preferred Duct Sealing Company

Hollis has been part of the Garrison Partners family since 2004. The Garrison Standard means we arrive inside the quoted window, price the job in writing before touching anything, and leave the site clean. In Annapolis, that standard matters because many homes present access challenges: tight Historic District streets, shared building systems downtown, and crawlspaces too low to stand in.

Our technicians are background-checked and uniformed. You know who’s arriving before they walk in. Phones are answered by a live person 24 hours a day, 7 days a week. No voicemail loops, no callback queues.

Every job carries our 365-Day Done Right Promise. If the seal fails or the musty odor returns within a year, we come back and make it right at no charge, including a free second visit. We put that in writing on every Annapolis job.

We serve Annapolis neighborhoods from the Historic District to Annapolis Roads, from downtown rowhouse conversions to the colonials and ranches of the Broadneck peninsula. The housing stock varies, and so does our approach.

Duct Insulation in Annapolis

Duct Insulation in Annapolis is often the companion to sealing, especially in homes with ductwork running through unconditioned crawlspaces or attics. Without insulation, even a perfectly sealed duct loses conditioned air to the surrounding space. In Annapolis’s climate, that surrounding space is frequently damp, hot in summer and raw in winter, which forces your HVAC system to work harder and drives up energy bills.

We typically recommend duct insulation when we find sweating ducts, temperature drops of more than a few degrees between the air handler and the far registers, or when sealing alone won’t prevent condensation from forming on the exterior of the duct. In Annapolis’s bay-humid environment, this is common in crawlspace runs and attic trunks.

Whole-home duct insulation in Annapolis generally falls between $1,200 and $3,000, depending on linear footage, accessibility, and whether we’re working with rigid metal or flex duct. We price by the system, not by the foot, and we write that price down before any work begins.

Condensation Control in Crawlspace Runs

In Annapolis, ducts in unconditioned crawlspaces sweat when cold supply air meets humid bay air. Insulation with a proper vapor barrier prevents that condensation, which protects the seal and stops mildew from forming on the duct exterior. We use professional-grade materials from Honeywell and Abatement Technologies, specified for the humidity levels we measure on site.

Attic Trunk Insulation for Energy Loss

Attic temperatures in Annapolis can exceed 130°F in July. Uninsulated attic trunks act like radiators, dumping cooled air into the hottest part of the house. We insulate these runs with wrapped fiberglass or closed-cell foam, depending on clearance and existing conditions, to keep the air you paid to cool actually reaching your rooms.

HVAC Duct Sealing in Annapolis

HVAC Duct Sealing in Annapolis addresses the leaks, gaps, and disconnected joints that let conditioned air escape before it reaches your living space. In a typical Annapolis home, we measure duct leakage with a pressure pan and blower door, then seal accessible joints with mastic or mechanical fasteners, depending on the duct type and location. The goal is simple: the air your system produces should end up in your rooms, not your crawlspace or attic.

We recommend HVAC duct sealing when homeowners report uneven temperatures between rooms, dust blowing from registers, musty odors when the system runs, or utility bills that climb without explanation. In Annapolis, these symptoms often trace back to retrofitted ductwork in historic homes, where original construction never anticipated forced air.

Whole-home HVAC duct sealing in Annapolis typically costs $800 – $2,400. Smaller repairs to accessible sections may run $400 – $900. We inspect first, quote in writing, and only proceed when you approve the exact scope and price.

Pressure Testing Before and After

We don’t guess. Our crews test duct leakage with a calibrated blower door and pressure pan before sealing, then test again after. You see the numbers. In Annapolis’s older housing stock, pre-sealing leakage often exceeds 30% of total airflow. A proper seal typically reduces that to under 10%.

Mastic vs. Tape for Damp Environments

In Annapolis’s humid crawlspaces, standard foil tape often fails within a season as ducts sweat and flex. We use water-based duct mastic rated for damp conditions, applied to clean, dry surfaces. In extreme moisture situations, we address the vapor source first, then seal. Sealing over active condensation is a temporary fix that traps problems inside the system.

Trusted Brands We Service in Annapolis

Our Annapolis crews carry professional-grade equipment from Rotobrush, Nikro, and Abatement Technologies, plus filtration and insulation products from Honeywell and Aprilaire. We don’t use hardware-store tape and shop-vacs. The negative-air machines and rotary brush systems we deploy are the same tools found on commercial jobs, sized appropriately for residential ductwork. Because we stock common sealing and insulation materials locally, most Annapolis jobs are completed in a single visit without waiting on parts. If your system uses specialized components, we’ll tell you during the estimate and source them before we schedule the work.

Common Duct Sealing Problems We See in Annapolis Homes

• Historic District crawlspace moisture intrusion. In downtown Annapolis, retrofitted flex duct often runs through unsealed, dirt-floor crawlspaces that stay damp from the high water table. Sealing joints without first addressing that moisture traps musty air inside the system, and the odor returns within a season.
• Sagging flex duct contacting damp soil. When retrofit duct sags and touches crawlspace floor, standard mastic or tape peels as the duct sweats through Annapolis’s humid summers. We support and reroute the duct before sealing, or the repair fails.
• Shared return plenums in rowhouse conversions. Downtown Annapolis has many buildings divided into multiple units with a common return chase. Sealing one unit’s ducts without addressing that shared pathway lets air and moisture migrate between apartments, undermining the seal and spreading odors.
• Rust-flaked galvanized runs near tidewater. In low-lying Annapolis neighborhoods, older galvanized duct in crawlspaces corrodes from constant humidity. We identify these sections during camera inspection and replace them before sealing, because mastic won’t adhere to rust scale.

Pricing for Duct Sealing in Annapolis, MD

We Also Serve Cities Near Annapolis

Our crews regularly work in Riva, Crownsville, Arnold, and Edgewater, where many of the same bay-humidity and housing-stock conditions apply. Whether you’re in a waterfront property on the South River or a colonial off General’s Highway, we price by the system and stand behind the work for a full year. Duct Sealing in Annapolis and surrounding communities follows the same standard: written price, written guarantee, job done by the book.

FAQs About Duct Sealing in Annapolis