Roof Insulation Guide

R-Value & Material by Climate Zone

This guide explains how to choose the right roof and attic insulation by climate zone, material type, and budget. Cold zones (5-8) require R-49 to R-60 in the attic; mixed zones (3-4) need R-38 to R-49; warm zones (1-2) need R-30 to R-38. Material options include fiberglass batt (cheapest, DIY-friendly), blown cellulose (best for retrofits), blown fiberglass (mold-resistant), and closed-cell spray foam (highest R per inch but most expensive). Pair with our Insulation Calculator.