HVAC / Furnace Permit Requirements in St. Louis, MO
Independent city (not part of St. Louis County). Uses 2018 IRC with local amendments. Requires licensed contractors for most work.
When you DO need a permit
Replacing an HVAC system (even same-for-same) requires a mechanical permit.
Estimated fee: $75 – $250
Typical timeline: About 1 week
Source: St. Louis City Revised Code / 2018 IRC with local amendments
Installing a new HVAC system requires mechanical and possibly electrical permits.
Estimated fee: $150 – $500
Typical timeline: About 2 weeks
Source: St. Louis City Revised Code / 2018 IRC with local amendments
Modifying or installing ductwork requires a mechanical permit.
Estimated fee: $75 – $250
Typical timeline: About 1 week
Source: St. Louis City Revised Code / 2018 IRC with local amendments
Installing a mini-split system requires mechanical and electrical permits.
Estimated fee: $75 – $250
Typical timeline: About 1 week
Source: St. Louis City Revised Code / 2018 IRC with local amendments
Replacing an HVAC system (even same-for-same) requires a mechanical permit.
Estimated fee: $75 – $250
Typical timeline: About 1 week
Source: St. Louis City Revised Code / 2018 IRC with local amendments
Installing a new HVAC system requires mechanical and possibly electrical permits.
Estimated fee: $150 – $500
Typical timeline: About 2 weeks
Source: St. Louis City Revised Code / 2018 IRC with local amendments
Installing a mini-split system requires mechanical and electrical permits.
Estimated fee: $75 – $250
Typical timeline: About 1 week
Source: St. Louis City Revised Code / 2018 IRC with local amendments
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Frequently Asked Questions
Estimated permit fees for HVAC / Furnace projects in St. Louis, MO range from $75 – $250. Fees vary based on project scope and valuation.
It depends on the specifics of your project. Some smaller HVAC / Furnace projects may be exempt from permit requirements, while larger ones typically require a permit. Use our free lookup tool to check your specific situation.
Working without a required permit in St. Louis can result in fines, stop-work orders, being required to remove completed work, and complications when selling your home. It's always best to check first.
Typical approval time for HVAC / Furnace permits in St. Louis is About 1 week. More complex projects may take longer if plan review is required.
Learn More About HVAC / Furnace Permits
Read our complete guide covering permit requirements, costs, common exemptions, and the application process.
Read HVAC / Furnace Guide →