What R-Value Do I Need? — ZIP Code Lookup
Enter your ZIP code and this tool returns the 2021 IECC-recommended R-value for walls, ceiling, floor, and basement in your climate zone — plus the wholesale fiberglass products that match.
Enter any US ZIP code. The tool works offline — no server call.
2021 IECC R-Value Table by Climate Zone
The tool above returns these same values based on your ZIP. Here they are as a static reference for downloading, printing, or checking against a specific zone.
Source: 2021 IECC prescriptive R-value table (Table N1102.1.3). Values shown are prescriptive minimums. Some jurisdictions have adopted stricter local amendments.
R-Value Lookup FAQ
Are these values legal minimums?
Yes, the values shown are the 2021 IECC prescriptive minimums for new construction, adopted by most US jurisdictions. Local codes can impose higher minimums but rarely lower ones. Check with your local building department for any jurisdiction-specific amendments.
Should I install more than the minimum R-value?
Going one R-value step up from the minimum (say, R-25 in a zone requiring R-19) typically pays back within 5 to 10 years through energy savings. Going two or more steps up rarely justifies the added material cost. The sweet spot for most homeowners is the code minimum plus one step.
Do these values apply to metal buildings and pole barns?
The IECC values are for occupied residential and commercial structures. Unconditioned storage buildings are exempt. Heated or air-conditioned metal buildings and pole barns are subject to the same values as any other building in that zone. Our wholesale fiberglass insulation is available in every R-value the IECC requires.
My ZIP code returned an unexpected zone. Why?
Climate zones sometimes cut across county lines, especially in mountainous or coastal areas. If you are close to a zone boundary (typical in Colorado mountains, coastal California, western Washington), verify with your local building department. Text 303-594-8373 and I can look up your specific county.
Do these values include continuous insulation (CI)?
For most zones the IECC prescriptive path shows cavity R-value alone (e.g., R-13 to R-19 in a 2x4 wall). Alternative paths using continuous insulation (foam board over sheathing) reduce required cavity R-value. The values shown are the cavity-only prescriptive path, which is the simplest to meet with fiberglass batts.
Now Price Your Insulation
Take the R-value the tool returned and price it in the calculator. See wholesale rate, freight to your state, and buyer-offered service fee range as three separate lines.