To achieve the greatest efficiency i ve read that the insulation should be 1 from the glazing on the glass and by my measurements the glass panes do sit in the middle of our heavy 2 wooden door.
													
																	Thermal insulation windows and doors. 
									
		
	
	
		
	
	
		
	
	
		
	
																	Glass or patio doors especially sliding glass doors lose much more heat than other types of doors because glass is a very poor insulator. 
																	Thermal windows have panes of glass that are separated by a insulated gas filled gap. 
																	It s a great insulator and perhaps the best cost effective way to insulate your windows. 
																	U value also known as thermal transmittence is used for measuring heat transfer rates in walls windows doors floors and roofs. 
															
													
									
		
	
	
		
	
	
		
	
	
		
	
																	Most modern glass doors with metal frames have a thermal break which is a plastic insulator between inner and outer parts of the frame. 
																	Thermal windows doors manufactures our replacement windows and patio doors with the highest quality vinyl materials. 
																	Adding a window insulation kit to the paned glass door may or may prove to not make a huge difference in my home s ability to conserve heat but i m optimistic. 
																	This keeps the cold air out with a pocket of air between the window and the plastic. 
															
													
									
		
	
	
		
	
	
		
	
	
		
	
																	Use a window insulation kit to add a barrier over your entire window and window frame.