Montana pricing
Air Duct Replacement Cost Calculator — Montana
Estimate duct replacement cost from your home's size, run count and how hard the attic or crawlspace is to work in. Every figure below is already adjusted for Montana labor and material pricing.
Model reviewed August 2026
Does ductwork replacement cost cost more in Montana?
+0% versus the national baseline
Installed prices in Montana track the national baseline. Permit fees are about 12% lower than the national average. Owner-builder permits common.
Bozeman and Whitefish price like resort markets while the rest of the state prices well below the national baseline; snow load drives structural scope statewide.
Compare with the national average ductwork replacement cost calculator.
Estimated total cost
$7,095 – $10,077
- Cost per square foot
- $4
- Cost per supply run
- $806
Estimates only. Local pricing, site conditions and code requirements change the real number.
What changes the number in Montana
| Local cost indexAbove the national baseline | 1.00x national |
|---|---|
| Permit fee index | 0.88x national |
| Code basisStatewide code applies | Montana Residential Code, based on the IRC, where adopted locally |
| Owner-builder posture | Owner-builder permits common |
| Largest markets | Billings, Missoula, Bozeman |
The formula
Cost = (sq ft x rate) + (runs x per-run cost) x access multiplier + permit
Duct replacement is priced mostly by labor hours. Tight crawlspaces and low attics can add 30–50% over an open, walkable space.
Covered markets in Montana
City-level cost and permit pages with local building department links.
Frequently asked questions
How much does it cost to replace ductwork?
Whole-home duct replacement usually runs $3,500 to $12,000 in 2026, or roughly $2 to $4 per conditioned square foot.
Should I replace ducts with the HVAC system?
If ducts are over 20 years old, undersized or badly leaking, doing both at once saves labor and protects the new system's efficiency rating.
Sources
Sources & verification
- Montana Building Codes Bureau
- ENERGY STAR sizing and efficiency guidance
- ACCA Manual J / Manual S sizing standards
- AHRI equipment performance directory
- International Code Council (IRC/IBC)
Model vintage August 2026. The links above are the issuing agencies' own pages — we publish them so you can confirm the current rule yourself, not as evidence that each fact on this page was re-checked with them today. Cost figures are modeled estimates based on national baselines adjusted for local labor and material pricing, not quotes. Permit rules change; confirm with the building department before starting work.