I just listened to something on the radio about foam insulation & they were saying how much better it is than the fiberglass. Prior to my new HVAC being installed, i was going to have non chemical fiberglass intalled in my attick. How much better is the foam vs fiberglass? The discussion I heard is that it seals everthing if used properly. They never discussed pricing, though - is it much more expensive than the normal stuff? I have a 2 story 4k sq. ft. home & don't want to invest in something if the cost outweigh the benefits.