Residential Mechanical / HVAC Permit in Nampa, Idaho
Required for all mechanical equipment installations in Nampa residences, including furnaces, air conditioners, heat pumps, gas piping, ductwork, gas fireplaces, and HVAC replacements. Governed by the 2018 International Mechanical Code and 2018 International Fuel Gas Code.
Verified 2026-06-29 · Source
When you need this permit
- All mechanical equipment installations require a permit before work begins
- Must be performed by a licensed mechanical contractor holding a valid Idaho Contractor's License
- Gas piping installers must hold a state of Idaho gas piping license
- Homeowner exception: owner of R-3/R-4/U occupancy may perform own mechanical work if residing in dwelling within 180 days after completion
- Hardship exception: immediate family member may perform work for family member unable to do so
- Unvented gas fireplaces require supplemental whole-house ventilation strategy (Nampa local amendment to IMC section 903)
Required documents
- Req
Mechanical Permit Application (2024)
Nampa Building Department mechanical permit application; available at cityofnampa.us/DocumentCenter/View/18814
Fee schedule
| Fee type | Amount | Notes |
|---|---|---|
| New residential dwelling (R-3/R-4) mechanical — under 2,000 sq ft habitable area | $180.00 per dwelling unit | Nampa Exhibit A — New Group R sub-contractor permit fee (covers installations within the dwelling unit) |
| New residential dwelling (R-3/R-4) mechanical — 2,000+ sq ft habitable area | $325.00 per dwelling unit | — |
| Residential mechanical (additions/remodels) — base fee | $36.00 base | Nampa Exhibit A — base fee for all residential sub-trade addition/remodel permits |
| Mechanical equipment (residential, additions/remodels) — per appliance | $15.00 per piece of equipment | Nampa Exhibit A — Mechanical Extras: 'Mechanical equipment (residential only) $15.00' |
| Venting without new appliance (residential only) | $15.00 | Nampa Exhibit A — Mechanical Extras |
| Gas piping pressure test | $15.00 | Nampa Exhibit A — Mechanical Extras |
| Reinspection (after first reinspection for same item) | $55.00 flat fee | — |
Review timeline
~3–7 business days
Typical estimate — confirm current times with the Nampa building department
Inspection process
- 1
Gas Piping Pressure Test
Required before concealing gas piping — verify no leaks under test pressure
- 2
Rough-In / Equipment
HVAC equipment, ductwork, and gas lines rough-in before walls closed
- 3
Final
Equipment operational, combustion air verified, venting correct, controls functional
Tips
- Nampa's local amendment requires unvented gas fireplaces to have a supplemental whole-house ventilation strategy (air-to-air heat exchanger or engineered system) — plan for this before installing an unvented gas fireplace.
- Ductwork must be properly sized for room-by-room calculated heating and cooling loads per Nampa's local mechanical requirements.
- All ductwork must be sealed and provide balanced supply/return air flow per Nampa's adopted IMC amendments.
- Gas piping work requires a separate mechanical permit even if combined with a furnace replacement.
- Idaho law allows homeowners to perform their own mechanical work on their primary/secondary residence provided they reside there within 180 days of completion.
Frequently asked questions
- Do I need a permit to replace my furnace in Nampa?
- Yes. Furnace replacement requires a mechanical permit. For a remodel/addition, the fee is $36 base plus $15 per piece of mechanical equipment = $51 per Nampa's Exhibit A fee schedule. Homeowners may pull their own permit.
- Can I install an unvented gas fireplace in Nampa?
- Yes, but Nampa has a local amendment requiring that unvented gas fireplaces be paired with a supplemental whole-house ventilation strategy (such as an air-to-air heat exchanger or engineered ventilation system) to mitigate combustion by-products. The system must operate any time the fireplace is in use.
Sources & verification
Verified against official sources. Last reviewed 2026-06-29.
- Nampa Building Safety & Code Department — official building department
- Trade Permit Process — Mechanical | City of Nampa
- Mechanical Permit Application (2024)
- Nampa Exhibit A — Schedule of Permit Fees (Dec 21, 2021)
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 Nampa building department before you submit. PermitBase is an independent reference and is not affiliated with any government agency.
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