HVAC Permit Requirements in Union, IL
Village of Union handles its own building permits (McHenry County only covers unincorporated areas, not incorporated villages). Building Inspector is available one hour per week, Tuesdays 3 PM to 4 PM. The village has not published its adopted residential code edition online; rules below use IRC 2021 as baseline (the most common adoption in the Chicago metro). No published fee schedule, no online application portal. Apply in person during Village Hall hours or email permits@unionillinois.org. Illinois state plumbing code (IDPH-licensed plumbers) and electrical licensing requirements apply regardless of local code adoption.
By Joey, Founder · Last verified April 18, 2026 · How we research →
When you don’t need a HVAC permit in Union
Minor duct repair (sealing, patching, replacing a short section) does not require a mechanical permit in Union, IL under 2021 IRC R105.2. Verify with the Village Building Inspector at (815) 923-4153 (available Tuesdays 3 PM to 4 PM) before starting work.
When you need a HVAC permit in Union
Replacing a furnace, AC condenser, or heat pump in the same location requires a mechanical permit in Union, IL because of refrigerant handling, gas connections, and combustion air requirements under 2021 IRC M1305. Verify with the Village Building Inspector at (815) 923-4153 (available Tuesdays 3 PM to 4 PM) before starting work.
Installing a brand new HVAC system or adding ductwork to a previously unconditioned space requires a mechanical permit in Union, IL with electrical and possibly gas sub-permits under 2021 IRC. Verify with the Village Building Inspector at (815) 923-4153 (available Tuesdays 3 PM to 4 PM) before starting work.
What Makes Union Different
Here's how Union's hvac rules stack up against the standard IRC baseline that most of the country follows.
More Lenient Than the IRC
Minor duct repair (sealing, patching, replacing a short section) does not require a mechanical permit in Union, IL under 2021 IRC R105.2. Verify with the Village Building Inspector at (815) 923-4153 (available Tuesdays 3 PM to 4 PM) before starting work.
2 rules match the IRC baseline, no surprises there.
HVAC Permit Costs: Union vs. Nearby
| City | Estimated Fee |
|---|---|
| Union | N/A |
| Chicago | $82 – $1,100 |
| Aurora | $64 – $850 |
| Joliet | $60 – $800 |
Fees shown are estimates based on local building code data. Actual fees may vary based on project scope and valuation. See all Union permit costs →
Estimated Project Timeline in Union
Here's a typical timeline for a hvac project in Union, IL:
Timeline is based on Union's typical about 2 weeks permit processing time. Actual timelines vary by project complexity, completeness of application, and current department workload.
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Frequently Asked Questions
Contact Union's building department for current HVAC permit fee information. Fees typically vary based on project scope and valuation.
It depends on the specifics of your project. Some smaller HVAC 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 Union 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 permits in Union is about 1 week. More complex projects may take longer if plan review is required.
Learn More About HVAC Permits
Read our complete guide covering permit requirements, costs, common exemptions, and the application process.
Read HVAC Guide →