Indiana REScheck Requirements (2026)

Key facts:

• 2020 Indiana Residential Code (2018 IRC)

• Climate Zones 4A & 5A

• Blower Door: 5 ACH50 or Visual Inspection

• No Fixed Code Adoption Schedule

 

Indiana commonly requires REScheck for: new residential construction, residential additions, major energy-related alterations, conditioned detached structures, barndominiums and ADUs. REScheck is explicitly recognized as an approved compliance software tool in the 2020 Indiana Residential Code.

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Indiana jurisdictions require REScheck documentation for residential permit applications under the 2020 Indiana Residential Code (675 IAC 14-4.4), based on the 2018 International Residential Code with Indiana-specific amendments, effective December 26, 2019. Indiana's code is administered by the Fire Prevention and Building Safety Commission and is mandatory statewide for Class 2 structures (one- and two-family dwellings).

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Indiana amended the base IRC blower door requirement from 3 ACH50 to 5 ACH50 — making it more builder-friendly than most neighboring states. A visual inspection alternative is also available. Enforcement is handled by local building officials or DSPS where no local official exists.

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Current Energy Code in Indiana

Indiana's residential energy code is embedded within the 2020 Indiana Residential Code (675 IAC 14-4.4), administered by the Indiana Department of Homeland Security's Fire Prevention and Building Safety Commission, based on the 2018 IRC with Indiana-specific amendments. Unlike many states, Indiana has no fixed schedule for adopting new code editions — updates depend on the commission's review process, requiring approval through the Building Code Review Committee, the Office of Management and Budget, and ultimately the Governor's Office.

• 2020 Indiana Residential Code (675 IAC 14-4.4) — based on 2018 IRC — effective December 26, 2019

• Applies to Class 2 structures: one- and two-family dwellings statewide

• No fixed code adoption cycle — updates are regulatory, not scheduled

• As of 2011, any update adding more than $1,000 in construction costs requires full legislative process

• Commercial/Class 1: 2021 IBC effective December 13, 2021

• Indiana Energy Conservation Code (675 IAC 19) governs commercial buildings using ASHRAE 90.1

 

Common Permit Requirements

• REScheck compliance report — explicitly referenced as approved software in N1102.1.5

• Manual J HVAC load calculations (equipment sizing per N1103.7)

• Manual S equipment selection documentation

• Window and door schedule (U-factor and SHGC per NFRC)

• Insulation R-value specifications and Grade I installation documentation

• Air leakage compliance — blower door test (5 ACH50 maximum) OR visual inspection per Table N1102.4.1.1

• Duct leakage test results (when ducts outside thermal envelope): 4 CFM25/100 sq ft post-construction

• Energy certificate posted at furnace/utility room at project completion

 

Indiana's Blower Door Amendment: Indiana amended Section N1102.4.1.2 of the 2018 IRC to set the air leakage threshold at 5 ACH50 — not the base code's 3 ACH50. This is a meaningful difference from neighboring Illinois (3 ACH50 mandatory) and Ohio. Indiana also retained the visual inspection option as a fully valid alternative, making it one of the more builder-friendly air sealing compliance structures in the Midwest.

 

Indiana's Three Compliance Pathways

Pathway  ·  How It Works

• Prescriptive (Table N1102.1.2):  Meet all R-values and U-factors by climate zone. REScheck accepted as documentation. Most common path for new construction.

• UA Trade-Off (REScheck):  Total building envelope UA ≤ reference design UA per N1102.1.5. REScheck explicitly named as approved calculation tool. Allows component trade-offs.

• Simulated Performance (N1105):  Whole-building energy modeling; proposed annual energy cost ≤ 95% of standard reference design. ERI/HERS path also available under N1106.

 

Indiana Climate Zones

Indiana spans two IECC climate zones divided roughly along a horizontal line through the middle of the state. Zone 5A covers the majority of Indiana including Indianapolis, Fort Wayne, South Bend, Lafayette, Muncie, and the entire northern half. Zone 4A covers the southern tier of counties including Evansville, Terre Haute, Bloomington, Columbus, and the Ohio River valley communities.

Zone  ·  Coverage  ·  Classification  ·  Primary REScheck Focus

• 4A:  Southern Indiana — Evansville, Terre Haute, Bloomington, Columbus, New Albany, Jeffersonville, Vincennes, Bedford   —   Mixed-Humid   —   SHGC 0.40 max, R-38 ceilings, R-13+5ci or R-20 walls, blower door 5 ACH50

• 5A:  Central and Northern Indiana — Indianapolis, Fort Wayne, South Bend, Lafayette, Muncie, Anderson, Gary, Kokomo, Elkhart   —   Cool-Humid   —   R-49 ceilings, R-20+5ci or R-13+10ci walls, deeper slab depth, blower door 5 ACH50

 

Zone 4A vs. Zone 5A Prescriptive Requirements

Requirement  ·  Zone 4A  ·  Zone 5A

• Ceiling:  R-38 (R-30 at eave condition)   —   R-49 (R-38 at eave condition)

• Wood Frame Walls:  R-13+5ci or R-20 cavity   —   R-20+5ci or R-13+10ci (cavity-only NOT permitted)

• Floor:  R-19   —   R-30

• Basement Walls:  R-10/13   —   R-10/13

• Crawlspace Walls:  R-10/13   —   R-15/19

• Slab Edge:  R-10 at 2 ft   —   R-10 at 2 ft

• Window U-Factor:  0.32 max   —   0.32 max

• SHGC:  0.40 max   —   No maximum

• Skylights:  0.55 max   —   0.55 max

 

⚠ Zone 4A/5A Boundary Alert: The boundary runs east-west through the middle of Indiana. Indianapolis (Marion County) is Zone 5A. Bloomington (Monroe County) and Terre Haute (Vigo County) are Zone 4A. Morgan, Owen, Putnam, and Clay counties sit near the boundary — always confirm the correct zone before completing documentation. Zone 5A requires R-49 ceilings and continuous wall insulation; entering Zone 4A values for a Zone 5A project is a significant compliance failure.

 

Air Leakage and Blower Door Requirements

Option A: Blower Door Test

• Maximum air leakage: 5 ACH50 at 50 pascals — Indiana's specific amendment to the base IRC

• Testing per RESNET/ICC 380, ASTM E779, or ASTM E1827

• Performed after rough-in and after installation of all envelope penetrations

• Written, signed test report provided to building official

• Passing is now a standard part of obtaining a Certificate of Occupancy in most jurisdictions

 

Option B: Visual Inspection

• Envelope tightness accepted when items in Table N1102.4.1.1 are field-verified

• Covers joints, windows, doors, recessed lights, attic hatches, plumbing/electrical penetrations, HVAC boots, fireplace walls

• Widely used in smaller markets and rural counties where testers may be less accessible

• Grade I insulation installation required and verified visually — no gaps, voids, or compression

 

Indiana's 5 ACH50 threshold is more lenient than neighboring Illinois (3 ACH50 mandatory) and Michigan (4 ACH50 mandatory), but stricter than Wisconsin (7 ACH50 or visual inspection). Builders working the Indianapolis-Chicago or Fort Wayne-Toledo corridors should not apply Indiana's threshold to projects across state lines.

 

Is REScheck Required in Indiana?

• New single-family homes

• Duplexes and townhomes

• Conditioned residential additions

• Finished basement conversions

• Garage conversions to conditioned space

• Conditioned sunrooms and bonus rooms

• Conditioned barndominiums

• Accessory dwelling units (ADUs)

 

Class 2 vs. Class 1: The 2020 Indiana Residential Code applies to Class 2 structures (one- and two-family dwellings). Multifamily buildings of three or more units are Class 1, governed by the 2021 Indiana Building Code and ASHRAE 90.1. REScheck does not apply to Class 1 structures.

 

Indiana-Specific Compliance Notes

• REScheck explicitly recognized in N1102.1.5 as an approved software tool for UA trade-off compliance

• Building framing cavities may NOT be used as supply ducts or plenums (N1103.3)

• Supply ducts in attics: R-8 minimum insulation; other ducts outside thermal envelope: R-6 minimum

• Duct post-construction leakage maximum: 4 CFM25 per 100 sq ft (when outside thermal envelope)

• Energy certificate must be posted at furnace location, utility room, or approved location at completion

• HVAC equipment must be sized per Manual J or equivalent method (N1103.7)

• Whole-house mechanical ventilation required if dwelling air leakage is less than 5 ACH50 per N1103.5

 

Common REScheck Failure Reasons in Indiana

Most Common Errors

• Zone 4A/5A misidentification — entering R-38 for a Zone 5A project where R-49 is required; common near the boundary in Morgan, Hendricks, Owen, Putnam, and Clay counties

• Missing continuous wall insulation in Zone 5A — cavity-only R-20 not permitted on the standard prescriptive path

• Zone 4A SHGC missing or exceeded — 0.40 max frequently omitted on Ohio River projects with large south/west glazing

• R-38 eave exception misapplied in Zone 5A — satisfies R-49 only at the specific eave condition

• Missing basement wall insulation — R-10/13 required in both zones

• Window U-factor above 0.32 maximum in either zone

 

Mechanical & Envelope Issues

• Blower door failures from rim joist bypasses, uncaulked top plates, recessed lighting, poorly sealed attic hatches

• Duct leakage failures — unconditioned attic duct systems with unsealed boots/connections

• Grade I insulation installation failures — compressed batt insulation is a frequent correction

• Framing cavity used as supply duct — prohibited under N1103.3

• Missing energy certificate at final inspection

• Mechanical ventilation not provided when blower door results fall below 5 ACH50 (N1103.5)

 

Major Cities and Jurisdictions in Indiana

Indianapolis (Marion County — Zone 5A)

Indiana's largest city and most active permit market enforces the full 2020 Indiana Residential Code, including R-49 ceiling insulation and continuous wall insulation. The metro — including Hamilton, Hendricks, Johnson, and Boone counties — is one of the fastest-growing residential markets in the Midwest.

 

Fort Wayne (Allen County — Zone 5A)

Northern Indiana's largest city has an active building department enforcing the full 2020 Indiana Residential Code, including R-49 ceiling and continuous wall insulation.

 

South Bend & Elkhart (Zone 5A)

Northern Indiana's manufacturing corridor, including the RV manufacturing hub around Elkhart. Full Zone 5A requirements apply. South Bend's Lake Michigan proximity adds latent cooling load considerations for Manual J.

 

Evansville (Vanderburgh County — Zone 4A)

Indiana's southern Ohio River city has the most mixed-climate conditions in the state. SHGC 0.40 control is particularly important. Zone 4A applies: R-38 ceilings, R-13+5ci or R-20 walls.

 

Bloomington (Monroe County — Zone 4A)

A major university city that's Zone 4A despite its central location — R-38 ceiling requirement applies, not Zone 5A's R-49. Adjacent Morgan, Owen, and Lawrence counties should verify zone carefully.

 

Lafayette & Tippecanoe County (Zone 5A)

The Purdue University community drives steady residential construction. Full Zone 5A requirements apply; building officials are familiar with REScheck.

 

Frequently Asked Questions

What energy code does Indiana currently use?

The 2020 Indiana Residential Code (675 IAC 14-4.4), based on the 2018 IRC with Indiana-specific amendments, effective December 26, 2019. Energy requirements are in Chapter 11 (N1102 series). Indiana has no fixed schedule for adopting new editions — updates go through the Fire Prevention and Building Safety Commission, Building Code Review Committee, Office of Management and Budget, and Governor's Office.

 

What is Indiana's blower door requirement?

5 ACH50 maximum (675 IAC 14-4.4-95), more lenient than the base IRC's 3 ACH50. A visual inspection alternative (Table N1102.4.1.1) is fully valid. When blower door testing is performed, a written signed report must be provided to the building official.

 

What climate zones does Indiana have?

Zone 5A (Cool-Humid) covers the majority of the state including Indianapolis, Fort Wayne, South Bend, Lafayette, Muncie, Anderson, Gary, Kokomo. Zone 4A (Mixed-Humid) covers southern Indiana including Evansville, Bloomington, Terre Haute, Columbus, New Albany. The boundary runs roughly east-west through the middle of the state.

 

Is REScheck accepted in Indiana?

Yes — explicitly recognized in Section N1102.1.5 as an approved software tool for demonstrating UA trade-off compliance, widely accepted at Indiana permit offices for new construction and additions.

 

Does Indiana require REScheck for additions?

Additions must meet the code's requirements for new construction without requiring the unaltered existing building to comply. REScheck is accepted on the UA trade-off path. Verify submission requirements with the local building department.

 

Are barndominiums required to comply?

Yes, conditioned barndominiums must comply regardless of construction type. Spray foam insulation is especially useful for meeting both Grade I installation and the 5 ACH50 threshold given the large surface areas and steel framing typical of these structures.

 

Is Indianapolis in Zone 4A or Zone 5A?

Zone 5A — this surprises some builders who assume the capital is more moderate. Zone 5A requires R-49 ceiling insulation, continuous wall insulation, and R-30 floor insulation. Bloomington, by contrast, is Zone 4A.

 

What causes REScheck failures most often in Indiana?

Entering Zone 4A values for a Zone 5A project, missing continuous wall insulation in Zone 5A, missing/incorrect SHGC in Zone 4A, misapplied R-38 eave exception, missing basement wall insulation, and window U-factor above 0.32. Mechanically: blower door failures from compressed batt insulation and unsealed rim joists.