ENERGY STAR lists R60 for a Zone 4B attic with no insulation and R49 when 3–4 inches remain. Use the official county classification; Albuquerque is only the representative model.
What the official table recommends
| Condition | Guidance | Scope |
|---|---|---|
| Uninsulated attic | R60 | ENERGY STAR retrofit recommendation for Zones 4A and 4B. |
| Existing 3–4 inches | R49 | Official retrofit table condition |
This table compares attic R-values. It does not calculate bags or measure the gap in performance. Assess the existing insulation first, then match the required added R-value to a current product label.
What to check through the year
- Spring
Inspect coating, sealant, and exposed wood transitions.
Surface condition determines compatible preparation.
- Summer
Measure attic insulation coverage and access conditions.
Representative readings expose thin and displaced areas.
- Fall
Review air sealing around the ceiling plane.
Accessible leakage paths should be treated before top-up.
Before you plan the work
- Confirm the actual project zone using the cited official lookup or the authority that applies locally.
- Inspect existing material, moisture, air leakage, safe access, wiring, fixtures, and combustion equipment before top-up.
- Use the coverage chart on the current product label; do not transfer bag data between U.S. and Canadian products.
- Treat representative locations as classification examples, not local forecasts or code boundaries.
Sources and notes
Source links reviewed July 16, 2026. A review date is not the document's publication date.
- U.S. Department of Energy: Prototype Building Models — Climate Zone RepresentativesUnited States · government standard
Representative locations classify a zone; they are not a substitute for local weather or code data.
- Pacific Northwest National Laboratory: Guide to Determining Climate Zones by CountyUnited States · government standard
Use the county files for a project address; representative cities are examples rather than boundaries.
- ENERGY STAR: Recommended Home Insulation R-ValuesUnited States · government guide
Recommendations are presented by ENERGY STAR using 2021 IECC climate zones.
- ENERGY STAR: DIY Checks and InspectionsUnited States · government guide
Do not disturb suspected vermiculite insulation; obtain qualified guidance before work.