yeah, kind of like the stuff used on firewalls and on hvac applications etc. I did some research on the web and there are quite a few people who have used a material called 'reflectex'. It comes in a roll and you can get it at home depot. Some are using it for firewall etc. As long as it is not directly exposed to a heat source (ie exhaust) it is fine for shielding a filter box. It is supposed to deflect 97% of the heat, according to the company. Same material is used to make sun shades for cars...
