Between 9 18 4 the difference between the r values is caused by the thickness of the doors 1 model is 1 3 8 and the other model is 2.
													
																	R value of solid wood garage door. 
									
	
		
	
																	R values climb as thickness of the material increases. 
																	Even though it seems worse than other materials because wood has a lot of mass it actually can store energy not just prevent the ingress or egress of energy which is only what r values measure. 
																	A 2 1 4 inch solid core wooden door for example has an r value of 3 70. 
																	Higher is better when looking at garage door r values but it s not the only factor to consider. 
															
													
									
	
		
	
																	Today s garage doors with polyurethane insulation will have an r value of 12 18 garaga s residential garage doors provide up to r 18 but you also want to choose a door that has otherwise good construction. 
																	As a final tip understand that a garage door that has an r 16 value will actually help keep your home protected from heat and humidity during the summer months. 
																	Another thing that effecting the r value is the material of the insulation. 
																	There are mainly 2 materials for insulating garage doors polystyrene and polyurethane. 
															
													
									
	
		
	
																	You also add heat to the garage every time you open an interior access door from the main house to the garage. 
																	R value for solid wood doors this is a reprint of a recent article on some studies done to show that the straight r value of solid wood is misleading.