HVAC & Energy
Duct Insulation Area Calculator
Estimate straight-duct insulation wrap area, allowance and insulation volume. Compare SI/US results and review the method, assumptions and related references below.
Change any input to update the calculation. Unit changes preserve the physical quantity.
Inputs
Calculated locally in your browser. No sign-up or input upload.
Results
Bare duct surface
12.5664 m²135.2633 ft²Outside blanket surface
14.1372 m²152.1712 ft²Surface including allowance
15.5509 m²167.3883 ft²Insulation volume
0.3338 m³11.7878 ft³Outer wrap perimeter
1.4137 m4.6382 ftCalculation breakdown
- Result interpretation
- Estimate straight-duct insulation wrap area, allowance and insulation volume
Assumptions & checks
Outside straight-run geometry only; elbows, branches, overlaps and seam details need a separate allowance. This does not size airflow or certify insulation performance.
Formula
Estimate straight-duct insulation wrap area, allowance and insulation volume
Worked example
Using the default values shown in the calculator, the same formula gives the following result. This is a quick sanity check for the calculation, not a design recommendation.
Inputs
- Outside duct shape
- Round
- Bare outside duct diameter
- 0.4 m
- Length per straight run
- 10 m
- Identical runs
- 1
- Blanket thickness
- 25 mm
- Ordering allowance
- 10 %
Result
- Bare duct surface
- 12.5664 m²
- Outside blanket surface
- 14.1372 m²
- Surface including allowance
- 15.5509 m²
- Insulation volume
- 0.3338 m³
- Outer wrap perimeter
- 1.4137 m
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Technical references for this calculation
Frequently asked questions
What does this result tell me?
Outside straight-run geometry only; elbows, branches, overlaps and seam details need a separate allowance. This does not size airflow or certify insulation performance.
How can I check the calculation?
Worked example: A 0.4 m outside round duct, 25 mm blanket and 10 m run needs 14.137 m² outside surface; 10% allowance gives 15.551 m². Review each stated input and unit; use project-specific values rather than treating the editable example as a requirement.
Reference data & method sources
- NIST SI conversion factors
SI/US dimensional conversions. Geometry and energy balances are stated explicitly, not attributed to a design standard.