Standard Exterior Wall Insulation R Value

Recommended home insulation r values.

Standard exterior wall insulation r value.

If your exterior walls are constructed from 2 by 4 inch studs the most insulation that can go into the wall while retaining its r value is r 13 or r 15 as these are both made to fit a cavity 3 1 2 inches deep. Thickness density and type of materials are some factors that contribute to. Fiberglass batts for standard 2 4 walls are now available in low medium and high density products that range from r 11 to r 15. Depending on where you live and the part of your home you re insulating walls crawlspace attic etc you ll need a different r value.

The higher the r value the better the thermal performance of the insulation. R value is a measure of insulation s ability to resist heat traveling through it. For instance if you have a material with an r value of 12 attached to another material with an r value of 3 then both materials combined have an r value of 15. While wall insulation is limited by the width of the studs different materials provide higher or lower r values.

Try the r value calculator available through oak ridge. R value is a standard unit of measurement for determining among many things how effective your insulation will be. Note from this. Fiberglass vats are the standard insulator for 2 inch by 4 inch wall framing and are rated r 11 through r 15.

Insulation rolls rolled insulation is another type of insulation blanket similar to batt insulation. Because insulation fits the width and depth of the cavity between studs when you compress insulation to fit the space you remove its. Standard fiberglass batts have r values ranging from r 2 9 to r 3 8 for every inch of thickness but high density insulation batts can have r values as high as r 4 3 per inch. For example if you have a type of insulation that has an r value of r 5 per inch of thickness you will need a depth of 6 inches of this insulation installed in your attic to reach r 30 if you live in zones 2 or 3.

In order to achieve the higher insulation r value of r 21 a different type of. These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation. The table below shows what levels of insulation are cost effective for different climates and. Insulation level are specified by r value.

The r refers to absolute thermal resistance. For example a wall with 3 fiberglass batting r value of 10 8 11 9 may have an overall r value of nearly 14 because of siding sheathing and drywall. In simple terms r values measure the effectiveness of insulation and a higher number represents more effective insulation.