The only times a heat shield would have been useful on my Rem 870 would have been during shotgun defense classes.
You probably only need a heat shield on a home defense shotgun if you plan on shooting a lot and requiring several reloads. Otherwise, you can do without it.
"If you look through your scope and see your shoe, aim higher."
-- said to me by my 11 year old daughter before going out for hogs 8/13/2011