HVAC Permit Requirements in Dillon, MT

Dillon is a small town of 4,334 residents in Montana that follows the 2021 IRC. For hvac projects, Dillon follows the IRC pretty closely, no major surprises compared to what most cities require. You're looking at roughly $37 – $125 in permit fees, plan on about 1 week for approval, plus you can apply online.

By Joey, Founder · Last verified March 29, 2026 · How we research →

Population: 4,334 Code: 2021 Verified: 2026-03-29 4 local rules

When you need a HVAC permit in Dillon

Required·Rule 1

HVAC replacement requires a permit.

Estimated Fee$37 – $125
Typical Timelineabout 1 week
SourceMontana Building Code / 2021 IRC
Required·Rule 2

New HVAC type requires a permit.

Estimated Fee$50 – $200
Typical Timelineabout 2 weeks
SourceMontana Building Code / 2021 IRC
Required·Rule 3

Ductwork changes require a permit.

Estimated Fee$37 – $150
Typical Timelineabout 2 weeks
SourceMontana Building Code / 2021 IRC
Required·Rule 4

Adding central HVAC requires a permit.

Estimated Fee$75 – $250
Typical Timelineabout 2 weeks
SourceMontana Building Code / 2021 IRC

HVAC Permit Costs: Dillon vs. Nearby

Dillon comes in on the low side for Montana. You're looking at $37 – $250 here, compared to the state average of $78 – $282.

CityEstimated Fee
Dillon $37 – $250
Billings $75 – $500
Missoula $78 – $525
Great Falls $67 – $450

Fees shown are estimates based on local building code data. Actual fees may vary based on project scope and valuation. See all Dillon permit costs →

Estimated Project Timeline in Dillon

Here's a typical timeline for a hvac project in Dillon, MT:

Week 1
Get quotes & finalize design
Contact licensed contractors, get 3+ quotes, finalize project scope and drawings (plan drawings required).
Week 2
Prepare permit documents
Contractor prepares site plan, construction drawings, and permit application. Gather required documents per your city's checklist.
Week 3
Submit permit application
Your contractor submits the application to Dillon's building department, apply online here.
Week 4-5
Plan review & approval
Typical processing time in Dillon: about 2 weeks. Plan review examiner checks drawings for code compliance.
Week 6+
Construction & inspections
Post the permit card on site. Work begins. Schedule inspections at required stages (varies by project). Final inspection required before closing the permit.

Timeline is based on Dillon's typical about 2 weeks permit processing time. Actual timelines vary by project complexity, completeness of application, and current department workload.

Need an HVAC permit in Dillon, MT?

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Building Department Contact

NameDillon Building Department
Phone(406) 683-4245
WebsiteVisit website
Address125 S Idaho St, Dillon, MT 59725
HoursMon-Fri 8am-5pm
ApplyApply online

Frequently Asked Questions

Estimated permit fees for HVAC projects in Dillon, MT range from $37 – $250. Fees vary based on project scope and valuation.

It depends on the specifics of your project. Some smaller HVAC projects may be exempt from permit requirements, while larger ones typically require a permit. Use our free lookup tool to check your specific situation.

Working without a required permit in Dillon can result in fines, stop-work orders, being required to remove completed work, and complications when selling your home. It's always best to check first.

Typical approval time for HVAC permits in Dillon is about 1 week. More complex projects may take longer if plan review is required.

Learn More About HVAC Permits

Read our complete guide covering permit requirements, costs, common exemptions, and the application process.

Read HVAC Guide →

Estimate your permit fees →

Disclaimer: This information was last verified on 2026-03-29. Building permit requirements may change. Zoning requirements (setbacks, lot coverage, height limits) are separate and vary by location. Always confirm with your local building and planning departments before starting your project. PermitMint provides general guidance, not legal advice.