Do I Need a Permit to Replace a Furnace in Arizona?
Quick Answer
Yes — even a like-for-like furnace swap requires a mechanical permit.
Why Even a Swap Needs a Permit
Furnace replacements involve gas connections, venting, and combustion air — all safety-critical systems. Most jurisdictions require a mechanical permit to verify the new furnace is properly vented, has adequate combustion air, and the gas connections are leak-free. This is true even for exact same-model replacements.
High-Efficiency Conversions
Upgrading from a standard-efficiency (80%) to high-efficiency (90%+) furnace changes the venting requirements: standard units use metal B-vent, high-efficiency units use PVC/CPVC. The old metal vent chase may need to be sealed. A condensate drain line is also required for high-efficiency units.
What Inspectors Check
The final inspection covers: gas piping and drip leg, venting type and clearances, combustion air supply (especially in confined spaces), condensate drain (high-efficiency units), thermostat operation, and CO detector presence on every level.
Bundled with AC?
If you're replacing both the furnace and AC unit at the same time, one mechanical permit typically covers both. The inspector will check the AC refrigerant lines, electrical disconnect, and condenser pad in addition to the furnace items.
Bottom Line
Yes, always. The permit is $40-$75 and your HVAC contractor handles it. One final inspection. Don't skip it — CO poisoning from bad venting is real.
Permit fees by city in Arizona
Verified from each city’s published fee schedule. Where a city has no separate fee listed for this project, open the city page for the current requirements and amount.
| City | Permit fee | Source |
|---|---|---|
| Chandler | $100.00Verified | Mechanical / HVAC Permit → |
| Gilbert | Permitted under the general building permit — see city page | Residential Building Permit (New Single-Family Dwelling) → |
| Glendale | $29.79 base feeVerified | Mechanical / HVAC Permit → |
| Mesa | $0–$8,333: $220; $8,334–$16,667: $330; $16,668–$24,999: $440; $25,000–$200,000: $500 plus $6/each $1,000 over $25,000Verified | Mechanical / HVAC Permit (Stand-Alone) → |
| Peoria | Minimum fee $87. Valuation-based permit fee per Development Fee Schedule. There is no separate flat-fee mechanical schedule; valuation is based on the scope of work.Verified | Mechanical / HVAC Permit → |
| Phoenix | $1–$1,000: $195 base fee; $1,001–$10,000: $195 on first $1,000 plus $12 per additional $1,000; $10,001–$50,000: $303 on first $10,000 plus $10 per additional $1,000. Larger projects per Table A tiers.Verified | Mechanical / HVAC Permit → |
| Scottsdale | $121Verified | Mechanical / HVAC Permit → |
| Surprise | Base: $100 per permit. Valuation $1.00–$999,999.99: $6.00 per each $1,000 of valuation. Plus 0.50% administrative processing fee on valuation.Verified | Mechanical / HVAC Permit → |
| Tempe | Per Table 1-A tiers. For example: $2,001–$25,000: $197.78 for the first $2,000 plus $30.61 per additional $1,000. Plan Review Fee is 65% of the building permit fee, collected separately at application.Verified | Mechanical / HVAC Permit → |
| Unincorporated Maricopa County | $50 flatVerified | Mechanical / HVAC Permit → |