Minimum R Value For Wall Insulation

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.

Minimum r value for wall insulation.

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. Insulation level are specified by r value. R value is a standard unit of measurement for determining among many things how effective your insulation will be. 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. The whole construction is measured taking into account additions to the r value like the inherent r value of things like brick walls as well as subtractions caused by windows or any other. Minimum insulation r value requirements non residential above roof deck. This will determine the r values required for different parts of your home.

The r refers to absolute thermal resistance. These r value objectives aren t measured through insulation alone though. These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation. Higher r value numbers mean that the insulating material resists the cold or heat from the outside better.

R value based method of section c402 1 3 u c and f factor based method of section c402 1 4. Specific insulation requirements of section c402 2 thermal requirements of either. The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process. State applicable energy ashrae zone minimum r value state local ms mississippi ashrae 90 1 2010 2 r 20 3 r 20 state local mo missouri 2012 iecc 4 r 25 5 r 25 state only mt montana 2012 iecc 6 r 30.

Recommended home insulation r values. The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures. The values in this table can also be used as a guide when installing insulation into alterations and additions or retrofitting existing homes with no insulation. 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.

While wall insulation is limited by the width of the studs different materials provide higher or lower r values. Thickness density and type of materials are some factors that contribute to. The table below shows what levels of insulation are cost effective for different climates and.