Air Duct Repair & Replacement in Sacramento

Signs your ducts need repair

• One room never cools down. A back bedroom that stays 5 or more degrees warmer than the rest of the house often has a crushed or disconnected supply run.
• Weak or no airflow at a register. Hold your hand to each vent. A dead register usually means the duct feeding it has come off its boot or collar.
• The attic is cooler than it should be. If the attic feels like it's being air conditioned, it probably is.
• Dust, insulation fibers or a musty smell from the vents. A torn return duct can pull attic dust and insulation into the system.
• Scratching in the attic, droppings near ducts or chewed insulation. Roof rats and mice tear flex duct for nesting material.
• Higher bills with no change in use. Lost air means the system runs longer to reach the thermostat setting.

Why ducts fail in Sacramento attics

Sacramento summers bring long runs of 100°F afternoons, and attic air gets much hotter than that. Ducts up there take years of heat cycling, and the materials wear out.

• Flex duct sags and kinks. Flexible duct needs support every few feet. When straps fail or someone steps on it while storing boxes or running cable, it collapses and chokes airflow.
• Connections let go. Old cloth duct tape dries out in attic heat. The joint at the plenum or register boot slowly pulls apart until the run falls off.
• The outer jacket cracks. UV and heat make old plastic jackets brittle. Once the jacket and insulation tear, the inner liner is exposed and the duct loses its insulating value.
• Rodent damage. Rats and mice chew through flex duct and nest in the insulation. Damaged runs often carry droppings and urine and usually need replacement, not patching.
• Undersized or poorly laid-out systems. Many older homes had ducts added after the fact with long, twisting runs. Those rooms were never going to get enough air.

Government research shows how much is at stake. A U.S. Department of Energy-funded study by the National Renewable Energy Laboratory found that ducts in attics and crawlspaces can lose 25% to 40% of the heating and cooling energy passing through them, from leaks plus heat moving through the duct walls.

Repair, seal or replace: which do you need?

Option	What it is	When it fits
Spot repair	Reconnect, re-strap or replace one or a few damaged runs.	Most of the system is in good shape and the problem is local, such as a fallen run or one crushed section.
Duct sealing	Test for leakage, then seal leaks with mastic or an aerosol sealant.	The ducts are intact but leaky. See duct sealing.
Partial replacement	Replace a whole branch or the return side, often with a new plenum.	Damage is concentrated in one area, such as rodent damage over half the attic.
Full duct replacement	New supply and return ducts, plenums and boots, designed and sized for the home.	Ducts are old, brittle, undersized or widely damaged, or you're changing out the HVAC system anyway.

We inspect the whole system before recommending anything. A dead register is sometimes a five-minute reconnect, and sometimes the first sign that the whole system is past its useful life.

Duct replacement during a system changeout

If you're planning an AC replacement or a heat pump installation, look at the ducts at the same time. A new high-efficiency system connected to leaky, undersized ducts will not deliver its rated efficiency or comfort. Heat pumps in particular often need more airflow than the old AC was getting.

Replacing ducts during a changeout also means one permit, one set of inspections and one trip into the attic. When the ducts are 25 or more years old, they have often reached the end of their useful life too.

Title 24 rules for duct work in California

California's Energy Code (Title 24, Part 6) applies to duct work, not just equipment. At the time of writing (2026), the key points for homeowners are:

• Permits. Replacing an HVAC system or altering the duct system generally needs a building permit from the City of Sacramento, Sacramento County or your city.
• The 25-foot trigger. Since the 2022 code cycle, and still under the 2025 code, adding or replacing more than 25 feet of duct (down from 40 feet in the 2019 code) triggers the duct sealing and insulation requirements.
• Leakage testing. Altered and new duct systems must pass a duct leakage test verified by an independent HERS rater. Limits are tighter for an entirely new duct system than for an altered existing one.
• Insulation. Sacramento is in California Climate Zone 12. New ducts in an unconditioned attic need R-8 insulation there under the current prescriptive rules.

Your HERS rater and building department confirm the exact requirements for your permit. We plan the job around those requirements from the start.

Older homes: asbestos on duct joints

What does duct repair cost?

What moves the price:

• Scope. Reconnecting one run costs far less than replacing a branch or the full system.
• Access. Low-pitch attics, tight crawlspaces and heavy insulation slow the work.
• Rodent cleanup. Contaminated runs and insulation have to come out and be bagged.
• Code triggers. Work over the 25-foot threshold adds a permit and HERS testing.
• Design changes. Adding returns or resizing runs for a new heat pump adds materials and labor.
• Asbestos. Testing and abatement, if needed, are a separate cost.

How duct repair works

1. Inspection. We check airflow at each register, then go into the attic or crawlspace to trace every run, connection and plenum.
2. Findings with photos. You see what we found: disconnected runs, crushed sections, rodent damage, suspect materials.
3. Options and price. Spot repair, partial or full replacement, with the code requirements that apply to each.
4. Permit. When the scope triggers one, the permit is filed before work starts.
5. Repair or replacement. New runs are sized, supported off the attic floor where possible, connected with proper collars and sealed with mastic or listed tape.
6. Testing and sign-off. Airflow is checked at the registers. When required, the HERS rater tests duct leakage and the inspector closes the permit.

Where we repair ductwork

We repair and replace ducts throughout Sacramento and nearby communities, including Carmichael, Citrus Heights, Folsom and Roseville, plus Placer, El Dorado and Yolo county communities.

Related duct and air services

Air duct repair FAQ