Polyiso Insulation question

[rkantor]

Had a question. I am getting ready to put 1/2 r-max insulated sheathing. It is going against 7/16 osb sheathing on the walls of my garage. I plan on putting vinyl siding to match the house. It is single sided foil with a satin finish opposite side. The foil normally goes towards the inside to dead air space. However, I would have air space towards the siding. It probably is a stupid thing to worry about, but I was wondering if it would be better to face the foil out towards the vinyl. What are the thoughts on that.

 

[Warrenator]

Are you trying to keep the heat out or the heat in? The shiny side is supposed to reflect heat energy... might be marginally better at repelling the summer heat if the shiny side faces out, might be slightly better at keeping your warmth in during the cold winter shiny side in.

 

[MN4x4]

The foil is also a vapor barrier, so if you are in a cold climate ideally you want it toward the inside.

 

[rkantor]

Was looking at my heating and cooling days.....3536 for heating and 1766 for cooling at 65 setpoint. We have brutal summers with the humidity, but the winters rarely go below 20. We had about 2 inches of snow yesterday, it was seventy last week. I e mailed the manufacturer as well.

 

[rkantor]

Manufacturer states foil in, maybe they're worried about the vinyl getting too hot.