How to insulate garage door?

foxhound

Hi everyone, I’m planning to insulate my sectional garage door and am considering two options:

• 
  
  25mm Foilboard with 20mm spacers to create an air gap — https://www.bunnings.com.au/foilboard-green-25-x-2400-x-1200mm-insulation-panel_p0125959
  
  

• 
  
  30mm XPS foam  — https://www.bunnings.com.au/bastion-1200-x-600-x-30mm-xps-multi-use-foam-board_p0461085?srsltid=AfmBOoqe3qco9l4BVn9Pz1NY7JrDjS5kPXf8446VVS_-hWRvyzAJdm5k
  
  

My garage door faces west and gets quite hot in the afternoon. I’d like some advice on which of these two options would provide better insulation against the heat.

JacobZ

Hi @foxhound,

Thank you for your question.

Foilboard is the better choice for insulating a garage door because its reflective surface is designed to block radiant heat, which is the main source of warmth from the afternoon sun. 

Installing it with the aluminium foil layer facing out will reflect much of the incoming heat away, while the rigid insulation core slows the transfer of any remaining warmth. 

When installed with a small air gap, this combination forms a highly effective barrier that reduces both radiant and conductive heat flow. 

Let me know if you have any further questions.

Jacob

A note for our New Zealand readers - The use of foil-faced insulation products is banned in New Zealand.