Which way to install carpet underlay.......

[bandit67]

Hi Guys, need some opinions , please.  Am about to install some foil backed carpet underlay and am not sure which way it goes. All the tv shows show the foil to the inside of the car.  But when I read the directions on the roll , it says the foil goes towards the heat. I read that to say the foil glues to the floorboard. The guy I got the stuff from says he has seen it installed both ways and called the manufactor and they said install it foil to floorboard.   My old Buick came from the factory with that in both front floorboards.........installed foil up.  What is the correct way..................any ideas............thanks ...........John

[OttawaCharger]

I've only ever seen it on TV foil side up but if the manufacturer says to put it the other way, I'd be inclined to go with their advice.
which brand of underlay are you installing? Maybe someone here has used that particular brand.
Crutchfield has installation instructions (a video too) for the dynamat brand on their website.

[bandit67]

   It is called 3 in 1 Insulation , Heat Shield & Sound Deadener sold by Quality Heat Shield , part no 25070.  Ok, here is the exact wording for installation.
                Installing in engine compartment and floor boards, Aluminum Foil is always towards heat.
   
                Any other applications , the Aluminum Foil faces out.


       Sounds to me like foil to floor board and foil to inside of car on doors, package tray shelf, behind rear seat..........that sound right to yall.........J