Recommended R-values in zone 6
These follow US Department of Energy and ENERGY STAR recommended levels for existing homes. Local building code may require more — check before you start.
Attic
R-60
Unlimited depth — the cheapest R-value in the house
Walls
R-21
Minimum R-13
Capped by framing depth
Floors over unconditioned space
R-30
Minimum R-25
Matters most over vented crawl spaces
Crawl-space walls
R-19
Minimum R-15
For sealed, conditioned crawl spaces
Where zone 6 is
States whose most populous area falls in zone 6:
Representative cities: Minneapolis, MN · Burlington, VT · Helena, MT · Portland, ME.
Several states span three or more zones — California, Texas, Nevada, Arizona, Oregon, Washington, New York, New Mexico, and Idaho among them. Altitude matters as much as latitude. If you are near a boundary,check the map or confirm with your building department.
What insulating costs in zone 6
A 1,240 sq ft attic taken from bare joists to R-60 with blown cellulose, in this zone:
DIY total
$930–$1,650
Material, air sealing, blower, safety gear
Professional
$2,750–$5,450
Includes a 1.05× regional labor adjustment
Material needed
69 bags
17.1" of cellulose
Generated by the same engine as the calculator. Our assumptions.
What matters in this climate
- Ice dam prevention is a primary design concern, not an afterthought
- Attic hatches and recessed lights leak heavily at this temperature difference
- Closed-cell foam at rim joists is close to standard practice