Acceptable Attic Insulation R Value

Where you live different climates require different insulation r values.

Acceptable attic insulation r value.

If you compare the r value of sawdust and wood chips to our modern insulation products the insulation value is poor. Each state does have their own minimum insulation requirements which are often lower than the levels recommended by the department of energy. Typical fiberglass batt insulation has an r value between 2 9 and 3 8 per inch of thickness. If you are heating a home with wood chips in the attic then you are wasting.

Pa302 1 ceilings with attic spaces n1102 2 1 r402 2 1. These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation. Recommended home insulation r values. The higher the r value the better the thermal performance of the 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. Your home s age if your home is more than 10 year old you likely need more 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. 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.

R value is a measure of insulation s ability to resist heat traveling through it. Insulation level are specified by r value. The 2015 irc requires r 49 insulation for ceilings with attic spaces. So to achieve an r 49 you will need between 13 and 17 inches thick of batt insulation.

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. 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. There are many ways to retrofit a home with fiberglass and. However there is an exception.