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Mechanical / HVAC Permit in Longmont, Colorado

Required for heating, cooling, ventilation, and fuel-gas equipment installations in Longmont. Mechanical contractors need an ICC Master Mechanical certificate plus a $75 City of Longmont registration fee (Class D specialty).

Verified 2026-06-30 · Source

When you need this permit

  • Building permit required for furnace, boiler, A/C, evaporative cooler, or gas appliance installation/replacement
  • Mechanical contractors must submit a copy of their ICC Master Mechanical certificate to register with the City of Longmont
  • City registration fee of $75.00 required upon application approval
  • Proof of liability insurance required: $1,000,000 CSL / $2,000,000 general aggregate / $2,000,000 products-completed aggregate, naming City of Longmont as certificate holder Contractor

Required documents

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Fee schedule

Air Conditioners and Evaporative CoolersCity of Longmont FY2026 Fee Manual, Other Permits — Residential/Commercial table
$40.00
Furnace Replacement and BoilersFY2026 Fee Manual; if the permit application includes BOTH furnace and A/C, the combined fee is $50.00 flat
$40.00
Furnace + A/C combined permitFY2026 Fee Manual: 'If permit application includes furnace and A/C, the fee is $50'
$50.00
Gas Logs / Gas Inserts / Gas FireplacesFY2026 Fee Manual
$40.00
Wood-Burning Stoves / Fireplaces / Inserts / Pellet StovesFY2026 Fee Manual, footnote: 'A surcharge of $250 is added for wood-burning fireplaces'
$40.00 (plus $250 surcharge for wood-burning fireplaces specifically)
Hot Tubs and Above-Ground PoolsFY2026 Fee Manual
$40.00
Thermal InsulationFY2026 Fee Manual
$40.00
City Contractor Registration — Mechanical (Class D)FY2026 Fee Manual, Contractor License Fees table: 'Class D, Plumbing and Mechanical — $75 + $25*'
$75.00 upon application approval

Review timeline

Plan reviewTypical estimate — confirm current times with the Longmont building department
~0–0 business days

How long did your Mechanical / HVAC Permit permit actually take in Longmont?

Anonymous — one question, no email. Answers are combined and only shown once at least 5 people have reported.

Inspection process

  1. 1

    Rough-In / Equipment

    Equipment installation and ductwork before walls closed

  2. 2

    Final

    Equipment operational, combustion air and venting verified

See the full Longmont inspection guide — scheduling & re-inspection fees →

Tips

  • Bundling a furnace replacement with an A/C replacement on the same permit saves $30 versus filing them as two separate $40 flat-fee permits ($50 combined vs. $80 separate).
  • Wood-burning fireplaces carry a distinct $250 surcharge on top of the standard $40 permit fee — pellet stoves and inserts do not.
  • Mechanical contractors need an ICC Master Mechanical certificate (not a Colorado state-issued mechanical trade license) as the prerequisite credential for Longmont's Class D Mechanical registration.

Frequently asked questions

Longmont requires a mechanical / hvac permit for: Building permit required for furnace, boiler, A/C, evaporative cooler, or gas appliance installation/replacement; Mechanical contractors must submit a copy of their ICC Master Mechanical certificate to register with the City of Longmont; City registration fee of $75.00 required upon application approval; Proof of liability insurance required: $1,000,000 CSL / $2,000,000 general aggregate / $2,000,000 products-completed aggregate, naming City of Longmont as certificate holder. If your project isn't listed, confirm with City of Longmont — Building Services (Building Inspection Division), Development Services Center at (303) 651-8332 before starting work.

A standalone furnace replacement permit is $40.00. If the same permit application includes both a furnace and an air conditioner replacement, the combined flat fee is $50.00, per the City of Longmont FY2026 Fee Manual.

Plan review for a mechanical / hvac permit in Longmont typically runs 0–0 business days. This is an estimate, not a published figure — confirm current review times with City of Longmont — Building Services (Building Inspection Division), Development Services Center at (303) 651-8332.

You'll need: Mechanical Permit Application (via ACA portal). See the required-documents checklist on this page for details on each.

Longmont requires 2 inspection(s) for a mechanical / hvac permit, in order: Rough-In / Equipment, Final. Schedule each through City of Longmont — Building Services (Building Inspection Division), Development Services Center ((303) 651-8332).

Apply through City of Longmont — Building Services (Building Inspection Division), Development Services Center at 385 Kimbark St., Longmont, CO 80501. Phone: (303) 651-8332, email: building.inspection@longmontcolorado.gov. Office hours: Mon–Fri, 8 a.m.–5 p.m. (closed Federal holidays, Veterans Day, and the day after Thanksgiving; Building Inspection closed 10–11 a.m. on the 2nd and 4th Thursday for staff training). Official information: https://longmontcolorado.gov/building-inspection/permits/.

Longmont, Colorado has adopted: 2021 International Building Code (IBC) — adopted effective January 1, 2022; currently in force citywide; 2021 International Residential Code (IRC) — adopted effective January 1, 2022; currently in force citywide; 2021 International Energy Conservation Code (IECC) — adopted as part of the 2021 International Codes package effective January 1, 2022; 2021 International Fire Code (IFC) — adopted effective January 1, 2022; International Plumbing Code (IPC) and International Mechanical Code (IMC) / International Fuel Gas Code (IFGC) — adopted as part of the 2021 International Codes package effective January 1, 2022 (edition confirmed via Longmont's 2021 IBC/IRC Geographic Climatic Data Table; individual plumbing/mechanical/fuel-gas amendment ordinance text not independently re-verified beyond the city's codes-adoption page); 2023 National Electrical Code (NEC) — adopted with Longmont amendments, effective July 24, 2024; PENDING — NOT YET EFFECTIVE: 2024 International Codes plus the Colorado Energy Code Cohort's model amendments were scheduled for Longmont City Council consideration May 12, 2026, with an anticipated effective date of July 1, 2026. As of this extraction (lastVerified 2026-06-30), the City's own Building Code Update page still describes this as a pending/anticipated action, not a confirmed adopted-and-effective ordinance — DO NOT treat the 2024 codes as adopted until the city's codes page or Municode ordinance list confirms passage.. Local amendments apply — see the Longmont overview page for the full list.

Sources & verification

Verified against official sources. Last reviewed 2026-06-30.

Fees, timelines, and adopted codes are researched from each jurisdiction's published records — see how we verify. Requirements change and vary by project, so always confirm the current details with the Longmont building department before you submit. PermitBase is an independent reference and is not affiliated with any government agency.

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Mechanical / HVAC Permit in other cities

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