If you don't want to loose ceiling height, you will need to remove the celing covering to gain access to the floor joist cavities.
A product we've had great sucess with is Roxul (http://www.roxul.com ... read more
You mentioned this room being over a crawl space. We have found that most spaces are incorrectly conditioned.....or should I say say, not conditioned at all. Insulation is typically installed within t ... read more