Exterior Wall Insulation R Value

Higher r value numbers mean that the insulating material resists the cold or heat from the outside better.

Exterior wall insulation r value.

Recommended home insulation r values. 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. Insulation ratings are measured in r values per inch of thickness.

Typical recommendations for exterior walls are r 13 to r 23 while r 30 r 38 and r 49 are common for ceilings and attic spaces. See the department of energy s doe ranges for recommended levels of insulation below. Insulation r values vary based on the type thickness and density of the insulation material. 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.

2015 code requires walls to be insulated with a minimum of r 20 or r 13 5 13 5 means r 13 cavity insulation plus r 5 insulated sheathing. Exterior walls 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. The higher the r value the better the thermal performance of the insulation. This material offers the highest r values about r 6 to 6 5.

Thickness density and type of materials are some factors that contribute to r value. If structural sheathing covers 40 or less of the exterior continuous insulation r value shall be permitted to be reduced by no more than r 3 in the locations where structural sheathing is used. Insulation rolls rolled insulation is another type of insulation blanket similar to batt insulation. Some products have reinforced facing to make them sturdier.

Along with knowing the r value of a particular insulation it is also important to calculate the r value of a total system. An r value tells you how well a type of insulation can keep heat from leaving or entering your home. R value is a measure of insulation s ability to resist heat traveling through it. 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.

It provides about r 5 per inch. 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. Insulation level are specified by r value. The r refers to absolute thermal resistance.

R value is a standard unit of measurement for determining among many things how effective your insulation will be. Choose this option for areas that need a good amount of strength and water resistance. 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. The table below shows what levels of insulation are cost effective for different climates and.