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Thermal wrap and condensation scope
Duct Insulation Cost Calculator (2026)
Estimate R-6 or R-8 duct wrap by accessible length, attic or crawl-space access, old-insulation removal, air sealing, vapor barrier, and condensation conditions.
Direct answer
This page uses a broad modeled duct insulation reference of $7-$24 per linear foot. Project totals also depend on access, R-value, old-wrap removal, joint sealing, and moisture diagnosis. For example, 150 feet of attic ducts with R-8 insulation, old-wrap removal, and sealing selected produces about $2,250-$4,550 in this calculator, with no condensation diagnosis selected. This is a model example, not a local contractor quote; duct repair and remediation are separate. Use duct sealing for leakage and duct repair for crushed, torn, or disconnected sections.
Duct Insulation Cost per Linear Foot
Scope
Planning range
Why the range changes
Open basement or utility-area ducts
$7-$14 per linear ft
Good access can reduce labor; verify whether code or comfort goals require insulation in that space.
Low clearance, ground moisture, contamination, supports, and wet material can change or stop the work.
Remove old or wet insulation
$3-$8+ per linear ft
Disposal and safe handling are separate from new wrap; remediation is not assumed.
Correct Order of Work
1. Diagnose moisture. Find roof, plumbing, crawl-space humidity, condensation, or air-leakage sources before covering the duct.
2. Repair the duct. Replace crushed, torn, wet, contaminated, unsupported, or undersized sections.
3. Seal accessible joints. Treat leakage at seams, takeoffs, boots, and plenums before insulation hides them.
4. Install a continuous assembly. Specify R-value, sealed seams, vapor-barrier continuity, support, and clearance.
5. Verify. Inspect all sides, record dry conditions, and confirm airflow or leakage testing promised by the bid.
Condensation Is a Symptom
New wrap may fail again if humid air reaches a cold duct through gaps in the vapor barrier, if duct leakage chills the exterior, or if bulk water and crawl-space moisture remain. Require the contractor to name the suspected cause and the condition that will be verified before closure.
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R-6 vs. R-8 Quote Questions
What installed R-value and product are included, and which local requirement applies?
Does the stated value cover fittings, boots, plenums, and difficult transitions?
How will seams, penetrations, compression points, and vapor-barrier damage be closed?
Are supports being adjusted so insulation is not pinched or left against wet surfaces?
Which old material, cleanup, access, testing, and remediation items are excluded?
The modeled duct insulation reference on this page is $7-$24 per linear foot, with preparation and access changing the total. For 150 feet in an attic with R-8, old-wrap removal, and joint sealing selected, the calculator gives about $2,250-$4,550 before duct repair or remediation, with no condensation diagnosis selected. This is a model example, not a local contractor quote. Compare quotes using the same length and included work rather than multiplying a headline unit price by length alone.
Should ducts be sealed before they are insulated?
Usually, accessible joints and penetrations should be inspected and sealed before new insulation covers them. The proposal should separate air-sealing scope from thermal insulation and document large repairs first.
Is R-8 duct insulation better than R-6?
R-8 provides more thermal resistance, but the correct requirement depends on duct location, climate, adopted code, available clearance, and the complete assembly. Ask the contractor to state the installed R-value and code basis.
Will duct insulation stop condensation?
It can reduce surface condensation when the insulation and vapor barrier are continuous, dry, correctly installed, and suitable for the conditions. It will not fix bulk water, high crawl-space humidity, air leakage, missing vapor barrier, or undersized equipment by itself.
When should insulated ducts be replaced instead?
Consider replacement when ducts are crushed, torn, contaminated, wet through the liner, poorly sized, unsupported, or deteriorated across many sections. Do not pay to wrap material that cannot carry the required airflow.
Methodology
The estimator uses modeled allowances for accessible duct length, working location, target R-value, old-wrap removal, joint sealing, and condensation diagnosis. These figures are planning assumptions rather than a survey of local invoices. Ask the contractor to separate measured length and new wrap from preparation, physical repairs, and moisture-related work so proposals can be compared on the same scope.
For technical background, DOE guidance on sealed and insulated metal ducts explains the role of insulation and a vapor barrier for metal ducts in unconditioned spaces. ENERGY STAR duct sealing guidance recommends addressing accessible leaks and insulating accessible ducts. These references support the sealing and insulation scope; they do not supply or validate this calculator's dollar rates.
R-6 and R-8 in this tool are comparison options, not a statement that either value meets every local requirement. Confirm the complete insulation assembly, vapor-barrier details, and installed R-value against the product instructions and requirements for the actual project. Diagnose moisture before covering wet material; new wrap does not replace physical repair or remediation. Last updated October 29, 2026.
