I did a bit of homework on this before I decided what to go with because I needed heat guard for one car and noise guard for another. I went with different products for each condition. I used the duct wrap for the noise and some reflective bubble wrap for the heat. If you want to get real technicle you can go with some micro glass bead suspended in a coat of latex applied to the inside floor for heat insul. I don't personally know how well it works but it's something that I read about.