MM III = one broken source book.
Keep in mind this is sense, not sight. They can sense 'something' is around within 10 feet.
+5 if you have natural armor
+2 if you don't 'and' are wearing protective clothing
One of which is only useful if you are a spellcaster AND only applies to spells with the cold descriptor. Most beings around here are likely to have the cold subtype, negating it, or immunity and still take only half damage from cold with this feat.
If you don't like spellwarped, look at the half-dragon. This is NOWHERE near as powerful as that.