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.
													
																	Minimum attic insulation r value. 
									
	
		
	
																	You will need a higher r value of insulation if you live in the northeast than if you live in southern california. 
																	The higher the r value the better the thermal performance of the insulation. 
																	In general to optimally isolate an attic on average an r value of the insulation is required ranging from r 50 to r 60. 
																	Insulation level are specified by r value. 
															
													
									
	
		
	
																	Recommended home insulation r values. 
																	In zone 2 the average minimum requirement for attic insulation is 9 inches of r30 fill. 
																	There are many ways to retrofit a home with fiberglass and. 
																	Warmer climates only require an r 38 or higher or about 12 or more. 
															
													
									
	
		
	
																	How much insulation in attic for zones 1 4. 
																	The table below shows what levels of insulation are cost effective for different climates and. 
																	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. 
															
													
									
	
		
	
																	The average recommended level is 17 inches of r60. 
																	In zone 1 the average minimum requirement for attic insulation is 9 inches of r30 fill. 
																	Houses in a cold climate should have a minimum of r 49 in the attic which is equivalent to approximately 16 of fiberglass insulation.