Material | R value(ft^2 °F h/Btu |
Hardwood siding (1 in. thick) | 0.91 |
Wood shingles (lapped) | 0.87 |
Brick (4 in. thick) | 4.00 |
Concrete block (filled cores) | 1.93 |
Fiberglass batting(3.5 in. thick) | 10.90 |
Fiberglass batting(6 in. thick) | 18.80 |
Fiberglass board (1 in. thick) | 4.35 |
Cellulose fiber(1 in. thick) | 3.70 |
Flat glass (0.125 in thick) | 0.89 |
Insulating glass(0.25 in space) | 1.54 |
Air space (3.5 in. thick) | 1.01 |
Free stagnant air layer | 0.17 |
Drywall (0.5 in. thick) | 0.45 |
Sheathing (0.5 in. thick) | 1.32 |
Data from