new fan - vent cover or rain sensor?

I can just talk about what we have, so we have a thermostat controlled Fantastic Fan, with just a standard vent cover over it. We open and close the fan cover manually, but usually it just stays open. No rain sensor, because we didn't think it would work under the vent hood, as no rain ever gets to it. In our case, it is used to insure heat removal from the coach if power goes off, or when at home, just to keep it fromgetting too hot inside. We have had ours for many years, I think there are better options available now.