Attic Insulation R Value Code

Energy star states that an r 60 is equal to the best performing attic insulation.

Attic insulation r value code.

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 your attic to reach r 30 if you live in zones 2 or 3. There are many ways to retrofit a home with fiberglass and. Where you live different climates require different insulation r values.

You will need a higher r value of insulation if you live in the northeast than if you live in southern california. Achieving greater r values in exterior walls. 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. Your home s age if your home is more than 10 year old you likely need more insulation.

Recommended home insulation r values. R value is a measure of insulation s ability to resist heat traveling through it. The table below shows what levels of insulation are cost effective for different climates and. Insulation level are specified by r value.

In general to optimally isolate an attic on average an r value of the insulation is required ranging from r 50 to r 60. 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. Where using a simulated energy performance analysis sections of ducts that are installed in accordance with section 1103 3 6 located directly on or within 5 5 inches 140 mm of the ceiling surrounded with blown in attic insulation having an r value of r 30 or greater and located such that the top of the duct is not less than 3 5 inches 89. 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.

The insulation levels of an attic or of any part of a house are understood through the r value that is the value with which the insulating material is resistant to heat flow. For an attic the you could have an r 38 to meet the insulation code guidelines. Dte energy and consumers energy suggest an r 49 or above to be energy efficient. However if an r 38 was enough customers wouldn t ask why they re still too cold or hot in their home.

You can achieve better thermal performance in your attic by adding an additional layer of insulation. The higher the r value the better the thermal performance of the insulation. 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.