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
Required documents
- Req
Mechanical Permit Application (via ACA portal)
Online application through Accela Citizen Access
Fee schedule
| Fee type | Amount | Notes |
|---|---|---|
| Air Conditioners and Evaporative Coolers | $40.00 | City of Longmont FY2026 Fee Manual, Other Permits — Residential/Commercial table |
| Furnace Replacement and Boilers | $40.00 | FY2026 Fee Manual; if the permit application includes BOTH furnace and A/C, the combined fee is $50.00 flat |
| Furnace + A/C combined permit | $50.00 | FY2026 Fee Manual: 'If permit application includes furnace and A/C, the fee is $50' |
| Gas Logs / Gas Inserts / Gas Fireplaces | $40.00 | FY2026 Fee Manual |
| Wood-Burning Stoves / Fireplaces / Inserts / Pellet Stoves | $40.00 (plus $250 surcharge for wood-burning fireplaces specifically) | FY2026 Fee Manual, footnote: 'A surcharge of $250 is added for wood-burning fireplaces' |
| Hot Tubs and Above-Ground Pools | $40.00 | FY2026 Fee Manual |
| Thermal Insulation | $40.00 | FY2026 Fee Manual |
| City Contractor Registration — Mechanical (Class D) | $75.00 upon application approval | FY2026 Fee Manual, Contractor License Fees table: 'Class D, Plumbing and Mechanical — $75 + $25*' |
Review timeline
~0–0 business days
Typical estimate — confirm current times with the Longmont building department
Inspection process
- 1
Rough-In / Equipment
Equipment installation and ductwork before walls closed
- 2
Final
Equipment operational, combustion air and venting verified
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
- How much does a furnace replacement cost in Longmont?
- 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.
Sources & verification
Verified against official sources. Last reviewed 2026-06-30.
- City of Longmont — Building Services (Building Inspection Division), Development Services Center — official building department
- City of Longmont FY2026 Planning & Development Services Fee Manual (PDF)
- Contractor License Application — City of Longmont (PDF)
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.
Other permits in Longmont
Related guides
Get the AI compliance checklist
Upload your project scope, get a jurisdiction-specific checklist of everything you need. Coming soon.
We only use your email to send permit updates. No spam, unsubscribe anytime. Privacy.