Minimum R Value For Attic Insulation
The higher the r value the better the thermal performance of the insulation.
Minimum r value for attic insulation. Know exactly how much you need with our project calculators. 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. The table below shows what levels of insulation are cost effective for different climates and. The recommended level for most attics is to insulate to r 38 or about 10 to 14 inches depending on insulation type.
The higher the r value the greater the insulation performance. How much insulation in attic for zones 1 4. Recommended home insulation r values. The average recommended level is 17 inches of r60.
Meet minimum r values given in table 402 1 1 frame walls r 13 block walls interior insulation r 7 8 exterior insulation r 6 ceilings. 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. There are many ways to retrofit a home with fiberglass and. Insulating power or r value is only one factor to consider when building or improving a home to keep it comfortable.
The higher the r value the better the thermal performance of the insulation. 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. R value is a measure of insulation s ability to resist heat traveling through it. 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.
Ceiling insulation must be much higher at r 30 and a raised floor must be at least r 13. Performance compliance walls ceilings floors. In zone 1 the average minimum requirement for attic insulation is 9 inches of r30 fill. Where you live different climates require different insulation r values.
Maximum 20 of conditioned floor area. R value measures how well certain building insulation materials can resist heat. Add the right kind of insulation. Insulation levels are specified by r value.
Your home s age if your home is more than 10 year old you likely need more insulation. The average recommended level is 14 inches of r49. You will need a higher r value of insulation if you live in the northeast than if you live in southern california. Raised r 13 sog r 0 windows.
When determining how much insulation you need don t guesstimate calculate. Prescriptive compliance form 405. Insulation level are specified by r value. In zone 2 the average minimum requirement for attic insulation is 9 inches of r30 fill.
For block walls interior insulation must meet or exceed r 7 8 and exterior insulation must be r 6.