Commercial Duct Sealing San Jose & Bay Area

Key Takeaways

Common Question	Short Answer
Can ducts be sealed in an occupied apartment or office building?	Aeroseal reports that multifamily sealing can happen with tenants in place and without opening walls. We plan the schedule around your occupants during the assessment. Apartment duct sealing
How much does commercial duct sealing cost?	Commercial projects are quoted after a site assessment. The consultation is free. Request an assessment
How much leakage does Aeroseal remove in commercial ductwork?	Aeroseal reports 80–92% leakage reduction per sealed section, about 90% on average across its projects. Results vary by building. How it works
Can Aeroseal seal bathroom and kitchen exhaust shafts?	Aeroseal case studies describe sealing vertical exhaust risers in apartment buildings and hotels. Kitchen grease ducts are a separate, code-regulated system. Exhaust shaft sealing
What size leaks can it seal?	Holes up to about 5/8 inch. Larger openings and disconnected sections are repaired by hand first. How we repair ducts
Is the sealant safe for occupied buildings?	Aeroseal describes its sealant as non-toxic and ultra-low VOC, and it is used in hospitals, schools and government buildings. Air quality
Does San Jose regulate building energy performance?	San Jose's ordinance covers nonresidential and multifamily buildings of 20,000 square feet or more. Confirm your obligations with the City. Building performance standards

1. Why Duct and Exhaust Leakage Costs You Money

In a larger building, air travels through long trunk lines, ceiling plenums and vertical shafts before it reaches a unit, room or exhaust fan. Every leak along the way means your fans move air you never use. A NYSERDA study by Steven Winter Associates found that in the multifamily buildings it examined, over 50% of the air pulled by roof exhaust fans was drawn from building cavities through leaky ducts.

Leakage hits four parts of your operation:

Operating costs. Fans and air handlers run harder to deliver design airflow.
Complaints. Hot and cold units, stuffy rooms and weak bathroom fans.
Ventilation. Some spaces get too little fresh air while others get too much.
Indoor air quality. Leaky shafts can move odors and smoke between units.

2. Apartments and Multifamily Buildings

Most apartment buildings rely on central exhaust risers that pull air from kitchens and bathrooms up to roof fans, plus central or in-unit heating and cooling. When risers leak, lower floors often get weak exhaust and odors travel between units. Aeroseal reports that multifamily sealing can happen with tenants in place. For multifamily ductwork repair in San Jose and the wider Bay Area, see apartment and multifamily duct sealing.

3. Condos and HOAs

Condo buildings add a governance question. Common-area shafts and unit-owned ducts may fall under different responsibilities, and your CC&Rs decide who pays for what. Boards also need clear information to compare options and plan for the reserve fund. Our condo and HOA duct sealing page covers the board decision process, owner communication and unit access.

4. Hotels

Hotels share many multifamily problems: tall exhaust shafts, guest bathrooms on every floor and odors that turn into reviews. An Aeroseal-published case study describes a hotel that kept operating while shafts were sealed, with guests booked into rooms away from the shafts being worked on each day. See hotel duct sealing for scheduling and guest-impact details.

5. Office Buildings

Office ductwork usually runs above drop ceilings and through shared plenums, feeding zones with very different loads. Leaks in supply ducts can leave conference rooms stuffy and perimeter offices uncomfortable, and they make it harder to deliver the outdoor air the system was designed for. Work can often be scheduled after hours or by zone. Read more on office building duct sealing.

6. Common Duct Problems by Building Type

Building type	Common duct problems	What sealing addresses
Apartments and multifamily	Leaky exhaust risers, leaks at grille and roof-curb connections, uneven unit airflow	Leaks along the riser and branch connections, helping fans pull from units instead of wall cavities
Condos and HOAs	Shared shafts with unit-level leaks, unclear responsibility, odor complaints	Leaks in common shafts and, where owners agree, unit ductwork
Hotels	Tall bathroom exhaust shafts, weak exhaust on lower floors, musty odors	Shaft leakage that starves the lowest rooms of exhaust
Office buildings	Leaky supply trunks above ceilings, zones that never balance	Hidden supply and return leaks behind finished ceilings

Aerosol sealing handles the many small leaks. Disconnected, crushed or missing sections still need hand repair first, which is part of our commercial ductwork repair work in San Jose.

7. How a Commercial Assessment Works

A site assessment tells you how much your ductwork leaks, where, and what it would take to fix. It is also where we find out whether a system is a good fit for aerosol sealing at all.

Our Typical Commercial Assessment Process

Initial conversation. We discuss the building, the complaints you hear most, your occupancy and any deadlines.
Document review. Where available, we review mechanical drawings to understand shafts, trunks and how many systems are involved.
Walk-through. We inspect equipment, roof fans, accessible ductwork and possible access points for testing.
Measurements. Where the system allows, we measure leakage with calibrated test equipment and airflow at grilles with a flow hood.
Scope. We separate what Aeroseal can seal, what needs hand repair and what falls outside our work.
Written proposal. You get a written scope, a schedule plan for occupants and a quote.

Commercial projects are quoted after a site assessment. The consultation is free.

8. Scheduling Work Around Occupants

Most of your tenants, guests or staff will barely notice the work if it is planned well. Aeroseal reports that its process can be applied to an entire building or to individual sections, wings or rooms, which makes phasing possible. Typical scheduling options include:

Sealing one riser or zone at a time
Working in office buildings after hours or on weekends
Booking hotel guests away from active shafts
Giving tenants written notice of the dates and any brief unit access needed
Coordinating roof access and fan shutdowns with your maintenance team

9. Verification, Reporting and New Ductwork

Aeroseal reports that its leakage measurements follow Method D of ASTM E1554, a standard test method for duct leakage, and that pre- and post-seal leakage is always reported at the same reference pressure. The same system that measures the baseline runs during sealing, so you get a documented before and after result instead of an estimate.

If your project includes commercial ductwork installation in San Jose, such as replacing a damaged section, the new ductwork can be tested before ceilings close. Aeroseal notes its process can fit into the early phases of a project schedule. Confirm any code or verification requirements with your design team or building department.

Conclusion

Leaky ducts and exhaust shafts raise your operating costs, generate tenant and guest complaints and weaken ventilation. Because most of that ductwork is hidden, sealing it from the inside is often far less disruptive than opening walls and ceilings.

Every building is different, so commercial work starts with a free consultation and a site assessment. You'll see how much your system leaks, what needs repair first and how the work can fit around the people in your building.

Request a Free Building Assessment or call (408) 400-3630.

Commercial Duct Sealing for Bay Area Property Owners