What Metro's list says
From Metro Codes' list of projects that may or may not require a permit and its renovation page (read 23 October 2026), for one- and two-family homes:
| Job | Permit |
|---|---|
| Air conditioning, new and replacement unit | Yes, gas/mechanical |
| Furnace condenser replacement | Yes, gas/mechanical |
| Furnace, replace with different size or fuel | Yes, gas/mechanical |
| Heating system, changing size or change of fuel | Yes, gas/mechanical |
| Furnace or condenser repair | No |
| Exhaust fan | Yes, gas/mechanical |
| Ducted cooktop or countertop | Yes, gas/mechanical |
| Fireplace insert, wood stove | Yes, gas/mechanical |
| Attic fan | Yes, electrical |
Two consequences. The list has no separate heat-pump line; a heat pump's outdoor unit is a cooling unit too, so expect the same gas/mechanical permit and confirm with Codes. And the outdoor unit's power is its own item on Metro's electrical application ("HVAC- DISCONNECT"), so a new circuit for a unit means an electrical permit as well. The list does not name a same-size, same-fuel furnace swap; ask Codes (615-862-6500) rather than assume it is exempt.
Who can pull it
Metro's trades permit page: "Only licensed contractors with an e-permit account can apply for a trade permit using our online system"; everyone else applies in person at the Department of Codes and Building Safety, 800 President Ronald Reagan Way, weekdays 7:30 a.m. to 4:00 p.m., using the Gas/Mechanical Trade Permit Application.
| Credential | Who issues it | When it applies |
|---|---|---|
| Master mechanical, HVAC&R, or gas and appliance certificate | Metro's examiners board (Metro Codes) | The trade permit runs on it |
| Homeowner permit | The same board "shall also examine applicants for homeowner permits" | Your own home, your own work |
| CMC-C (HVAC) or CMC contractor's license | Tennessee Board for Licensing Contractors | When the HVAC part is "$25,000 or more" (Board) |
| Home improvement license | Tennessee Board for Licensing Contractors | Residential remodeling of $3,000 to $24,999 in Davidson County (Board) |
The usual Nashville HVAC permit is filed at $10,714, and the middle half of firms file between $7,500 and $28,500, so a full-system replacement can cross the $25,000 state line. Check the monetary limit on the state record if it does.
Fees and deadlines
We could not find Metro's current gas/mechanical fee table online; Codes calculates it at issue. Metro's trade applications set the clock: work must start within six months and be completed within two years of issue, and a permit becomes invalid if work is suspended for a year (Metro electrical application, read 23 October 2026).
Checking it afterwards
Search the address in ePermits or Metro's Parcel Viewer under Permit History. You should see a mechanical permit in your installer's name and, if a circuit was added, an electrical one, each with a passed final (Nashville building permit search).
What 29,714 Nashville HVAC permits show
| Measure | Nashville HVAC and gas |
|---|---|
| Permits on homes, September 2023 to September 2026 | 29,714 |
| Firms | 939 |
| Firms with one permit only | 379 (40.4%) |
| Firms with a permit in the last 12 months | 507 |
| Reached a final (permits a year or more old) | 75.6% |
| Usual filed value | $10,714 |
| 10th / 90th-percentile firm finished share (10+ permits) | 56.5% / 100.0% |
| Share of permits held by the busiest firm / five busiest | 10.0% / 24.3% |
| Busiest / quietest month | June (115) / December (85) |
HVAC is Nashville's weak trade for closing out: 75.6% reached a final, against 89.5% for electrical and 89.7% for plumbing. The average hides a split. Most busy firms finish well (the 90th percentile is 100.0%), but 36 of the 245 firms with 10 or more permits finish under 70%, and one of the busiest firms in the city carries a finished share far below the rest, which drags the total down. Read the firm's own share, not the city's. Filing peaks in June. Prices by job size are on Nashville HVAC cost, and monthly totals on Nashville permit statistics.
See every Nashville HVAC contractor by permits finaled →
Before you hire
Ask whose Metro mechanical or HVAC&R certificate the permit goes under, and for a $25,000+ job, the state license number; the steps are in Nashville contractor license lookup. Compare finals on the Nashville HVAC list. Other cities' rules are in do I need a permit for HVAC replacement, national prices in HVAC replacement cost, and the checklist in hiring an HVAC contractor.
What this does not tell you
We cannot time Nashville permits from issue to final, so there is no days figure here. Our HVAC group includes gas piping and other mechanical permits, not only AC and furnaces. Homeowner permits name the owner, not a firm. Metro's permit list was last revised in 2022.
How we know this
The permit list and trade-permit rules are quoted from Metro Nashville Codes pages and forms read 23 October 2026; the examiners board and state license rules from Metro Codes and the Tennessee Board for Licensing Contractors, read 22 October 2026. Permit counts are Metro Nashville Codes gas/mechanical trade permits on homes in Davidson County, September 2023 to September 2026; "reached a final" uses permits a year or more old.
Numbers come from Metro Nashville (Davidson County) building and trade permits, data through September 21, 2026. Nobody paid to be on this page and nobody can.
Questions
- Do I need a permit to replace an AC unit in Nashville?
Yes. Metro Codes' permit list marks 'Air conditioning, new & replacement unit' and 'Furnace condenser replacement' as needing a gas/mechanical permit for one- and two-family homes. A repair to a furnace or condenser does not need one.
- Do I need a permit to replace a furnace in Nashville?
Metro's list requires a gas/mechanical permit to replace a furnace 'with different size or fuel', and for any heating system 'changing size or change of fuel'. A same-size swap is not spelled out on the list, and a gas furnace involves gas piping, so ask Metro Codes on 615-862-6500 before treating it as exempt.
- Can a homeowner pull an HVAC permit in Nashville?
Metro's examiners board tests applicants for homeowner permits, and homeowners apply in person at the Department of Codes and Building Safety, 800 President Ronald Reagan Way. The online ePermits system is only for licensed contractors.
- How much is an HVAC permit in Nashville?
We could not find Metro's current gas/mechanical fee table online. The unit's electrical disconnect is a separate line on the electrical permit. Ask Codes on 615-862-6500 for the amount.
- How do I check my HVAC permit was finaled in Nashville?
Search your address in ePermits or the Parcel Viewer's Permit History. In our file 75.6% of Nashville HVAC permits a year or more old reached a final, lower than electrical or plumbing, so it is worth checking.
Build your own list
Every firm with that kind of permit on record. Pick what you value. The list moves.
Related guides
- Ames building permit search: how to look up permits on an address
- Do I need an HVAC permit in Ames? Yes: what is exempt, homeowner permits, the $56.23 base fee and inspections
- Do I need an HVAC permit in Anaheim? The mechanical permit for a furnace or AC change-out, fees and inspections
- Do I need an HVAC permit in Arlington, VA? The like-for-like exemption, the gas exception and zoning
- Do I need an HVAC permit in Scottsdale? The like-for-like AC swap, the $121 Minimum Mechanical Permit, and what needs plans
- Do I need a permit to replace a furnace in Seattle? Yes: the furnace permit, its $60.35 fee, and who can pull it
For one city
- List of building projects which may or may not require a permit — Metro Codes (accessed 2026-10-23)
- Building Permits Central: I Want to Renovate a Single-Family Residence — Metro Codes (accessed 2026-10-23)
- Obtaining a Trades Permit — Metro Codes (accessed 2026-10-23)
- Application for Electrical Permit — Metro Codes (accessed 2026-10-23)
- Mechanical, Plumbing, Electrical Examiners & Appeals Board — Metro Codes (2026-10-22)
- Subcontractors / Who is Required to be Licensed — Tennessee Board for Licensing Contractors (2026-10-22)
- Home Improvement Contractor — Tennessee Board for Licensing Contractors (2026-10-22)