HVAC Ductwork Installation & Sealing in San Jose, CA
Struggling with uneven airflow or high energy bills? We design, repair, and seal ductwork for balanced comfort in every room.
HVAC Ductwork in San Jose & the Bay Area
In many San Jose homes — especially those built before the 1990s — up to 30% of heated and cooled air never reaches the rooms, leaking instead into attics and crawlspaces through old, crushed, or disconnected ducts. If some rooms bake while others freeze, or your energy bills keep climbing, your ductwork is the likely culprit.
Promax designs, replaces, seals, and balances duct systems across Santa Clara County: new R-8 insulated runs, mastic-sealed connections, properly sized returns, and HERS-verified leakage testing required by California code. Better ducts make every system you own — furnace, AC, or heat pump — quieter, more efficient, and more comfortable.
HVAC Ductwork, Done Right
Here is what our HVAC ductwork work covers: system design and installation, repairs on every major brand, seasonal maintenance, and licensed, EPA-certified technicians on every job. Same-day service for no-cool, no-heat and no-hot-water calls, 7 days a week. Free in-home estimates on new systems and replacements.
- Full-system design, sizing, and installation
- Repairs on every major brand, with parts on the truck for most first visits
- Seasonal maintenance that prevents costly breakdowns
- Licensed, EPA-certified technicians for every job
What's Included With HVAC Ductwork
Every hvac ductwork visit covers the items below, and the scope and price are confirmed in writing before any work starts. When it's finished the technician walks you through what was done and what to watch for. We call back within one business hour, 7 AM – 10 PM.
- Duct leakage test with a documented before/after number
- New R-8 insulated supply and return runs where needed
- Mastic-sealed joints and connections, not just tape
- Properly sized returns so airflow is balanced room to room
Need HVAC ductwork help in San Jose?
Related Services
Most hvac ductwork jobs touch one of these, and the same licensed Promax team handles all of them. Each page lists what's included, typical costs and the questions San Jose homeowners ask most. Not sure which you need? Call (669) 777-1997 and we'll point you to the right one.
Where We Work
Promax Service Group serves homes and businesses in San Jose, across Santa Clara County, and in nearby Peninsula and East Bay cities. Same-day service for no-cool, no-heat and no-hot-water calls, 7 days a week. Choose your city for local details, or call (669) 777-1997 to confirm we cover your address.
Frequently Asked Questions
How do I know if my ducts are leaking?
Telltale signs: rooms that never reach temperature, dusty air, whistling sounds, high bills despite a newer system, and flex ducts visibly sagging in the attic. A duct leakage test gives a definitive number — California requires under 10% leakage on replacements (5% for new systems).
Should I repair or fully replace my old ductwork?
If the ducts are pre-1990 fiberglass duct board or brittle flex, full replacement usually pays off — old ducts are often undersized for modern equipment. Isolated damage or a few leaky joints can be sealed and insulated instead. We give you both prices.
Does new ductwork qualify for rebates?
Duct sealing and replacement can still qualify for utility efficiency rebates on their own, and we check for those at your free estimate. The federal 25C tax credit for combined HVAC/duct projects ended for installations after December 31, 2025, so we won't quote a credit that no longer applies — only rebates that are actually active.