Duct Sealing in Sunnyvale - Tested First, Written Price Second

Fast, Reliable Duct Sealing Across Sunnyvale

Duct sealing in Sunnyvale typically runs $450 – $1,200 for a whole-home system, depending on whether your ducts run through attic, crawlspace, or beneath the concrete slab. Most jobs take a half day, and we price them in writing before we touch anything. Call (361) 326-5060 for a free estimate.

Call (361) 326-5060

We’ve worked on enough Sunnyvale homes to know the difference between a standard ranch and a slab-on-grade Eichler off El Camino Real. Our crews dispatch from the San Francisco Bay Area office and carry the rotary tools and negative-air rigs needed for the silica dust that builds up in buried duct runs. Whether you’re in the Heritage District, near Sunnyvale-Saratoga Road, or closer to the Caltrain corridor, we arrive inside the quoted window, in uniform, with a written price in hand.

Our Duct Sealing team treats Sunnyvale’s housing stock as its own category. The mid-century builds here aren’t curiosities to us. They’re the majority of what we seal, repair, and clean.

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

Hollis has been part of the Garrison Partners family since 2004, and our Bay Area crews have built a reputation in Sunnyvale by showing up when we said we would and leaving the site clean. The 365-Day Done Right Promise covers every job in writing: if the seal fails within a year, we return and make it right at no charge, including a free second visit.

Our technicians are background-checked and uniformed, and phones are answered by a live person 24 hours a day, 7 days a week. No voicemail loops. No callback queues. When you’re trying to schedule around a workday on Mathilda Avenue or a school pickup near Washington Park, that matters.

We know the local conditions that break duct seals in Sunnyvale: seismic settling along the Calaveras Fault zone, dry rot in 60-year-old lumber, and the construction debris that infiltrates systems during the remodel booms hitting neighborhoods like Birdland and Ponderosa. That knowledge changes how we approach a job.

Duct Repair in Sunnyvale

Duct Repair in Sunnyvale often starts with a homeowner noticing uneven temperatures between rooms, a spike in PG&E bills, or the burnt-dust smell that hits Heritage District Eichlers every September. The repair involves finding the breach, whether it’s a separated joint in the attic, a crushed flexible run, or corrosion in slab-buried galvanized steel, then restoring airflow integrity. A typical repair in Sunnyvale runs $180 – $550 for accessible ductwork, while slab-duct access and repair can reach $800 – $1,400 depending on concrete work needed.

Slab-Duct Corrosion and Access

Many Sunnyvale ranches and Eichlers have supply or return ducts cast into the concrete foundation. Decades of moisture wicking through the slab corrodes the galvanized steel from the outside in. We use camera inspection to locate the damage, then evaluate whether spot repair, liner installation, or full duct replacement is the honest call. We don’t sell you a seal on a duct that’s structurally gone.

Seismic Joint Separation

The Calaveras Fault runs close enough that minor settling is routine in Sunnyvale’s older stock. Rigid metal ducts with lapped joints, standard in 1950s – 1970s builds, separate at the seams as the house shifts. We reseat the joint, mechanically fasten it, then seal with mastic rated for flex and temperature cycling. Foil tape alone won’t survive a season here.

Air Duct Sealing in Sunnyvale

Air Duct Sealing in Sunnyvale means something different than it does in San Jose or Santa Clara, where raised foundations put most ducts in crawlspaces or attics. Here, a significant share of homes have slab-on-grade construction with buried duct runs, and sealing must address both the accessible joints and the infiltration paths through cracked concrete. Whole-home sealing in Sunnyvale typically costs $450 – $1,200, with the higher end reflecting slab-duct conditions that need specialized prep and materials.

The Return-Air Plenum Check

Negative pressure at the air handler pulls air from wherever it can. In Sunnyvale’s Eichler and ranch slab homes, that often means through cracks in the return plenum concrete, drawing in silica dust, soil gas, and radon. Since the 2018 EPA radon zone map update, our crew checks this as standard practice. Sealing the plenum crack with Guardsman mastic and verifying with a smoke pencil isn’t an upsell. It’s part of doing the job by the book.

Mastic vs. Tape on Original Galvanized

Original 1950s – 1970s galvanized ducts with lapped joints expand and contract with every heating and cooling cycle. We use fiber-reinforced mastic, applied to clean metal, for a seal that moves with the joint. Standard foil tape cracks and peels within months on this hardware. The extra ten minutes of prep saves a callback.

Trusted Brands We Service in Sunnyvale

Our equipment roster includes Rotobrush rotary brush systems for agitating debris in buried duct runs, Nikro negative-air machines for controlled extraction, and sealing and filtration products from Guardsman, Honeywell, and Aprilaire. We stock Guardsman mastic and compatible mesh locally, so Sunnyvale jobs don’t wait on a parts run. For the Eichler and ranch homes that dominate this market, that means same-day completion on most standard seals and repairs. The tools are professional-grade, not hardware-store substitutes, and we explain what each one does while we’re working.

Common Duct Sealing Problems We See in Sunnyvale Homes

• Slab-duct silica infiltration: Buried concrete cracks let fine silica dust from the surrounding soil into supply and return runs. Standard sealing of attic joints ignores this path entirely, so the system keeps blowing particulates even after the visible work looks clean.
• Failed tape on seismic-flex joints: Lapped galvanized joints in original 1960s ductwork move with seasonal temperature swings and minor settling. Foil tape or un-reinforced mastic cracks within a year. We see this repeatedly in Birdland and Ponderosa ranches.
• Return plenum pulling construction debris: Sunnyvale’s remodel activity is constant, and negative pressure at the air handler sucks in drywall dust, insulation fragments, and silica from adjacent work. Sealing the plenum and verifying with smoke testing stops this upstream contamination.
• Overlooked air handler cabinet leaks: The cabinet itself, where the blower meets the plenum, often gaps at the seams. Sealing only the ductwork and ignoring the cabinet is like patching a tire and leaving a hole in the rim.

Pricing for Duct Sealing in Sunnyvale, CA

We Also Serve Cities Near Sunnyvale

Our Duct Sealing in Sunnyvale crews regularly work in Mountain View, Santa Clara, Cupertino, and Los Altos. The housing stock changes as you move south or west, raised foundations become more common, and the approach shifts accordingly. We know which neighborhoods have which construction types because we’ve sealed ducts in all of them.

FAQs About Duct Sealing in Sunnyvale