I've used Insulbrite many times with no problems. I put it in my place mats and hot pads. I use one layer of Insulbrite and two layers of Warm N Natural. It does keep the heat out nicely, however, there is condensation on the table when you pick them up. Insulbrite does have a top and a bottom. The side where you can see the silver stuff crinkly is the top and this is the side that should face the heat source. One thing I really like about Insulbrite is that it makes your item less flimsy. Place mats sit flat on the table and keep their shape well.
I've also used the quilted and non-quilted silver ironing board stuff. The quilted stuff is great, but can be difficult to quilt through because it's so thick. If I'm using just the silver stuff, I sandwich two layers of batting in between the silver stuff with the silver stuff on the outsides. Have made many pot holders this way. All of mine are now very thin on the inside after repeated washings, but still keep the heat out!