Acceptable Attic Insulation R Value

Insulation level are specified by r value.

Acceptable attic insulation r value.

The 2015 irc requires r 49 insulation for ceilings with attic spaces. 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. If you are heating a home with wood chips in the attic then you are wasting. So to achieve an r 49 you will need between 13 and 17 inches thick of batt insulation.

Often the depth of the wood shaving insulation was insufficient to today s standards and as it settled it has little or no thermal benefits. Where you live different climates require different insulation r values. This zone has a recommended r value of 30 to 60 for an uninsulated attic r25 to r38 for an attic with existing insulation and r13 to r19 for the floor. R value is a measure of insulation s ability to resist heat traveling through it.

There are many ways to retrofit a home with fiberglass and. Your home s age if your home is more than 10 year old you likely need more insulation. Recommended home insulation r values. Pa302 1 ceilings with attic spaces n1102 2 1 r402 2 1.

The table below shows what levels of insulation are cost effective for different climates and. These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation. Typical fiberglass batt insulation has an r value between 2 9 and 3 8 per inch of thickness. R 38 shall be deemed to satisfy the requirement for r 49 wherever the full height of uncompressed r 38 insulation extends over the wall top plate at the eaves.

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. The higher the r value the better the thermal performance of the insulation. However there is an exception. See the department of energy s doe ranges for recommended levels of insulation below.