What R-value do I need in my attic?

The DOE recommends R-30 for warm climates (Zone 1–2), R-38 for mixed climates (Zone 3–4), R-49 for cold climates (Zone 5–6), and R-60 for very cold climates (Zone 7–8). Higher R-values significantly reduce energy bills.

How many rolls of insulation do I need for a 1,000 sq ft attic?

For R-30 batt insulation in a 1,000 sq ft attic, each roll covers approximately 25 sq ft. With a 10% buffer: 1,100 sq ft ÷ 25 = 44 rolls. This will vary by brand — always check the roll's stated coverage on the packaging.

Advertisement (728x90)

🌡️

🛠️ Construction & DIY

Insulation R-Value & Roll Estimator

Calculate how many rolls or bags of insulation you need and determine the required R-value for your climate zone.

⚡ Instant 🆓 Free 🔒 Private

insulation r-value rolls batts blown-in energy efficiency

Area to Insulate (ft²)

Insulation Type

Climate Zone

Insulation R-Values & Climate Zones

The R-value measures insulation's resistance to heat flow — the higher, the better. The US Department of Energy divides the country into 8 climate zones, each recommending different R-values. Attics require the highest R-values since they lose the most heat in winter and gain the most in summer.

Recommended R-Values by Climate Zone

Zone 1–2 (FL, TX): Attic R-30, Wall R-13
Zone 3–4 (VA, KS): Attic R-38, Wall R-15
Zone 5–6 (IL, NY): Attic R-49, Wall R-20
Zone 7–8 (MN, AK): Attic R-60, Wall R-21

Roll vs. Blown-In Insulation

Batt/roll insulation is ideal for open cavities between studs and joists with standard spacing. Blown-in (loose-fill) insulation is best for attics, irregularly shaped areas, and retrofitting existing walls. It provides better air sealing but requires a blower machine.

Insulation R-Value & Roll Estimator

Rolls / Bags Required

Insulation R-Values & Climate Zones

Recommended R-Values by Climate Zone

Roll vs. Blown-In Insulation