this subject comes up all the time on RV forums.
semis can make it worthwhile since they drive so many miles, that the very small amount of benefit adds up.
but for regular RV'ers, they would have to drive miles and miles just to see any kind of minimal benefit and to recoup the costs of buying and installing a deflector.
and Zoe the Wonder Dog(R.I.P.)
'07 Roo 23SS pushing an '07 Chevy Avalanche
Equalizer WDH and Prodigy BC