Question 1

When should I replace my ductwork?

Accepted Answer

Replace existing ductwork when: 30+ year old galvanized or fiberglass duct showing deterioration, asbestos-containing duct (1950s-1970s) that has been disturbed, major ductwork damage (collapsed sections, animal damage, water damage), adding new HVAC system requiring different airflow design, failing HERS test repeatedly even after Aeroseal sealing, or major renovation changing home layout. Don't replace when Aeroseal can deliver 60-90% leakage reduction at lower cost or local repair can address specific damaged section.

Question 2

How long does duct installation take?

Accepted Answer

Single addition or ADU duct (1 zone): 2-3 days. Retrofit 3-bedroom home (1,500-2,000 sq ft): 3-5 days. Retrofit 4-bedroom home (2,000-3,000 sq ft): 4-6 days. Large home (3,000-5,000 sq ft): 5-8 days. Custom multi-zone with VAV controls: 1-2 weeks. From signed contract to completed install: typically 21-45 days including permit application, equipment delivery, and HERS testing scheduling.

Question 3

What's Manual D duct design?

Accepted Answer

Manual D is the ACCA standard for residential duct design. Accounts for total system airflow (CFM) based on equipment capacity, per-room airflow based on Manual J load calculation, trunk and branch sizing for static pressure under 0.5", return air pathway design, velocity limits (700-900 fpm in residences), insulation R-value per Title 24, and sealing class. Most LA HVAC contractors use rule-of-thumb sizing instead of Manual D. We do Manual D on every duct installation — it takes longer but delivers measurable performance.

Question 4

How much does duct replacement cost?

Accepted Answer

Single addition / ADU duct (1 zone): $1,800-$3,500. Retrofit 3-bedroom home (1,500-2,000 sq ft): $4,500-$7,500. Retrofit 4-bedroom home (2,000-3,000 sq ft): $6,500-$10,500. Retrofit large home (3,000-5,000 sq ft): $9,500-$15,500. Custom multi-zone with VAV: $12,500-$28,500+. Includes Manual D design, sheet metal trunk + flex duct branches, R-8 insulation, mastic + mesh tape sealing, HERS testing.

Question 5

Should I get Aeroseal or full duct replacement?

Accepted Answer

For most homes with intact but leaky ductwork: Aeroseal first ($1,500-$4,000, 60-90% leakage reduction). For severely damaged ducts, asbestos-containing ducts, or homes failing HERS test repeatedly even after Aeroseal: full replacement ($4,500-$15,500). For homes where ductwork is collapsed, disconnected, or animal-damaged: physical replacement is the only option. We diagnose at the in-home estimate and recommend the right approach for actual conditions.

Question 6

Do you handle ducted system installation on rebuilds?

Accepted Answer

Yes. Pacific Palisades and Altadena fire rebuilds frequently include full ductwork installation alongside HVAC equipment. Standard rebuild spec includes Manual D-designed ductwork meeting Title 24 2025 requirements: R-8 insulation in unconditioned spaces, sealed joints with mastic + mesh tape, HERS-tested duct leakage under 5% (passing threshold). We coordinate with general contractors on rebuild projects to install ductwork during construction phase. See our Pacific Palisades service area for context.

Question 7

What insulation R-value is required for ductwork?

Accepted Answer

Title 24 2025 requires R-8 insulation on supply ducts in unconditioned spaces (attics, crawlspaces, garages). R-6 minimum on supply ducts in conditioned spaces. Return ducts have lower requirements but we typically install R-8 on returns also for consistency and future-proofing. Older homes may have R-4 or no insulation on existing ducts — replacement project bringing ducts to current code adds significant insulation upgrade.

Project	Typical cost	Time
Single addition / ADU duct (1 zone)	$1,800–$3,500	2–3 days
Retrofit 3-bedroom home (1,500–2,000 sq ft)	$4,500–$7,500	3–5 days
Retrofit 4-bedroom home (2,000–3,000 sq ft)	$6,500–$10,500	4–6 days
Retrofit large home (3,000–5,000 sq ft)	$9,500–$15,500	5–8 days
Custom multi-zone with VAV	$12,500–$28,500+	1–2 weeks

Duct Installation & Replacement in Southern California — New Construction & Retrofit

When duct replacement is needed

Manual D duct design

Duct types we install

Sheet metal (galvanized) duct

Insulated flexible duct (flex duct)

Rigid insulated round duct

Hybrid systems

Duct installation cost

Real-world example

Service area

Frequently Asked Questions

Service Area Dispatch