Find your zone on the map and then use the above insulation r value chart to determine the level of insulation you need to properly insulate your attic walls floors and crawlspaces.
													
																	Exterior wall insulation r value. 
									
	
		
	
																	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. 
																	1 2 exterior plywood has an r value of 0 63 and exterior wood bevel siding has an r value of just 0 80. 
																	R value is a measure of insulation s ability to resist heat traveling through it. 
																	The truth is this studs have an r value of 3 5. 
															
													
									
	
		
	
																	R value is a standard unit of measurement for determining among many things how effective your insulation will be. 
																	Insulation level are specified by r value. 
																	Thickness density and type of materials are some factors that contribute to. 
																	Recommended home insulation r values. 
															
													
									
	
		
	
																	For instance if you have a material with an r value of 12 attached to another material with an r value of 3 then both materials combined have an r value of 15. 
																	In simple terms r values measure the effectiveness of insulation and a higher number represents more effective insulation. 
																	Higher r value numbers mean that the insulating material resists the cold or heat from the outside better. 
																	The net effect on the r value of the wall with the studs transferring heat cold thru conductive properties is the actual rating of that. 
															
													
									
	
		
	
																	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 higher the r value the better the thermal performance of the insulation. 
																	The table below shows what levels of insulation are cost effective for different climates and. 
																	The overall r value of a wall or ceiling will be somewhat different from the r value of the insulation itself because heat flows more readily through studs joists and other building materials in a phenomenon known as thermal bridging. 
															
													
									
	
		
	
																	Other typical wall materials have similarly low values. 
																	The r refers to absolute thermal resistance.