Insulation Comparisons

Type R-value / Inch Embodied Energy1 Advantages Disadvantages
Airkrete (Magnesium Silicate) 3.9 - Non-flammable
Fills cavities fully
Expensive, Friable
Blown in blanket 4.2 - Expensive
Cellulose (dry) 3.2 600 Recycled Can Settle
Cellulose (wet sprayed) 3.5 600 Recycled Professionial install
Cotton 3.0 - 3.7 - Recycled Expensive
Fiberglass 3.2 4,550 Common Most contain formaldehyde
Needs careful installation
Fiberglass (rigid) 4.4 -
Icynene (Polyurethane) 3.6 - 4.3 - Seals, No CFCs Professional installation
Mineral Wool (batts) 2.8 - 3.7 -
Phenolic foam 4.8 - Professional installation
Polyisocyanurate 5.6 - 7.7 14,300 Expensive
Polystyrene, expanded (EPS) 3.6 - 4.4 18,000 Expensive
Polystyrene, extruded (XPS) 5.0 - Underground applications Expensive, HCFC-142b
Polyurethane (closed cell) 5.8 - 6.8 -
Straw 1.5 - Cheap Best in Strawbale buildings
Footnotes:
  1. BTUs for R-20 over 1 square foot.