R-Value Table

Insulation Values For Selected Materials

This table was put together from a variety of sources over a number of years starting in 1983. I was working on the Energy Hotline for the state of Iowa at the time and put together a fact sheet on R-values. I even made copies of some of the sources back then and still have them, but most do not have any indication on the copied pages as to who the source was. The table has also been continually added to and updated over the years, so there no way to provide complete credit for the information. Obviously, all the information in everyone's tables came from some research lab originally. I apologize to anyone whose information I may have borrowed without credit and will gladly add credit information when it is provided to me.

That being said, people are welcome to link to this table from their web sites, but they MAY NOT copy it and post it on any other web site without permission.

Use the R-value table below to help you determine the R-value of your wall or ceiling assemblies. To obtain a wall or ceiling assembly R-value you must add the r-values of the individual components together. See the following example:

Calculating Assembly Wall R-Value*
Formula: Assembly R-value = 1 / (Assembly U-value) = 1 / (U-studs x % + U-cavity x %)

Component	R-Value Studs	R-Value Cavity	Assembly R-Value
Wall - Outside Air Film (winter)	0.17	0.17
Siding - Wood Bevel	0.80	0.80
Plywood Sheathing - 1/2"	0.63	0.63
3 1/2" Fiberglass Batt		13.00
3 1/2" Stud	4.38
1/2" Drywall	0.45	0.45
Inside Air Film	0.68	0.68
Percent for 16" o.c. + Additional studs	25%	75%
Total Wall Component R-Values	7.11	15.73
Wall Component U-Values	0.1406	0.0636
Total Wall Assembly R-Value			12.03

* This example is just for wood frame construction. Steel studs are a more complicated calculation.

R-Value Table - English (US) Units

Material	R/ Inch hr·ft2·°F/Btu	R/ Thickness hr·ft2·°F/Btu
Insulation Materials
Fiberglass Batts	3.14-4.30
3 1/2" Fiberglass Batt		11.00
3 5/8" Fiberglass Batt		13.00
3 1/2" Fiberglass Batt (high density)		15.00
6 1/2" Fiberglass Batt		19.00
5 1/4" Fiberglass Batt (high density)		21.00
8" Fiberglass Batt		25.00
8" Fiberglass Batt (high density)		30.00
9 1/2" Fiberglass Batt		30.00
12" Fiberglass Batt		38.00
Fiberglass Blown (attic)	2.20-4.30
Fiberglass Blown (wall)	3.70-4.30
Rock Wool Batt	3.14-4.00
Rock Wool Blown (attic)	3.10-4.00
Rock Wool Blown (wall)	3.10-4.00
Cellulose Blown (attic)	3.60-3.70¹
Cellulose Blown (wall)	3.80-3.90¹
Vermiculite	2.13
Autoclaved Aerated Concrete	1.05
Urea Terpolymer Foam	4.48
Rigid Fiberglass (> 4lb/ft3)	4.00
Expanded Polystyrene (beadboard)	4.00
Extruded Polystyrene	5.00
Polyurethane (foamed-in-place)	6.25
Polyisocyanurate (foil-faced)	5.0-5.6
Construction Materials
Concrete Block 4"		0.80
Concrete Block 8"		1.11
Concrete Block 12"		1.28
Brick 4" common		0.80
Brick 4" face		0.44
Poured Concrete	0.08
Soft Wood Lumber	1.25
2" nominal (1 1/2")		1.88
2x4 (3 1/2")		4.38
2x6 (5 1/2")		6.88
Cedar Logs and Lumber	1.33
Sheathing Materials
Plywood	1.25
1/4"		0.31
3/8"		0.47
1/2"		0.63
5/8"		0.77
3/4"		0.94
Fiberboard	2.64
1/2"		1.32
25/32"		2.06
Fiberglass (3/4")		3.00
(1")		4.00
(1 1/2")		6.00
Extruded Polystyrene (3/4")		3.75
(1")		5.00
(1 1/2")		7.50
Foil-faced Polyisocyanurate (3/4")		5.40
(1")		7.20
(1 1/2")		10.80
Siding Materials
Hardboard (1/2")		0.34
Plywood (5/8")		0.77
(3/4")		0.93
Wood Bevel Lapped		0.80
Aluminum, Steel, Vinyl (hollow backed)		0.61
(w/ 1/2" Insulating board)		1.80
Brick 4"		0.44

Interior Finish Materials
Gypsum Board (drywall 1/2")			0.45
(5/8")			0.56
Paneling (3/8")			0.47
Flooring Materials
Plywood		1.25
(3/4")			0.93
Particle Board (underlayment)		1.31
(5/8")			0.82
Hardwood Flooring		0.91
(3/4")			0.68
Tile, Linoleum			0.05
Carpet (fibrous pad)			2.08
(rubber pad)			1.23
Roofing Materials
Asphalt Shingles			0.44
Wood Shingles			0.97
Windows
Single Glass			0.91
w/storm			2.00
Double insulating glass (3/16") air space			1.61
(1/4" air space)			1.69
(1/2" air space)			2.04
(3/4" air space)			2.38
(1/2" w/ Low-E 0.20)			3.13
(w/ suspended film)			2.77
(w/ 2 suspended films)			3.85
(w/ suspended film and low-E)			4.05
Triple insulating glass (1/4" air spaces)			2.56
(1/2" air spaces)			3.23
Addition for tight fitting drapes or shades, or closed blinds			0.29
Doors
Wood Hollow Core Flush (1 3/4")			2.17
Solid Core Flush (1 3/4")			3.03
Solid Core Flush (2 1/4")			3.70
Panel Door w/ 7/16" Panels (1 3/4")			1.85
Storm Door (wood 50% glass)			1.25
(metal)			1.00
Metal Insulating (2" w/ urethane)			15.00
Air Films
Summer	Interior Wall		0.68
	Exterior Wall		0.25
	Interior Ceiling Horizontal		0.92
	Interior Ceiling 45°		0.76
	Exterior Ceiling		0.25
Winter	Interior Wall		0.68
	Exterior Wall		0.17
	Interior Ceiling Horizontal		0.61
	Interior Ceiling 45°		0.62
	Exterior Ceiling		0.17
Air Spaces
1/2" to 4" approximately			1.00

Find R-Values for Natural Stone here:

¹ Measured Thermal Resistance of Cellulose Insulation Products Commercially Available in 2007

Back | Top

© 2000-2013 ColoradoENERGY.org
This site is currently maintained and hosted by Randy L. Martin of R. L. Martin & Associates, Inc.
Comments on the site and notification of items that could be included can be sent to: []

Last Updated: 07/16/2019

R-Value Table

Insulation Values For Selected Materials

Calculating Assembly Wall R-Value* Formula: Assembly R-value = 1 / (Assembly U-value) = 1 / (U-studs x % + U-cavity x %)

* This example is just for wood frame construction. Steel studs are a more complicated calculation.

R-Value Table - English (US) Units

Calculating Assembly Wall R-Value*
Formula: Assembly R-value = 1 / (Assembly U-value) = 1 / (U-studs x % + U-cavity x %)