[JRTJH]

The Heng retrofit fan comes in two models. The single speed exhaust fan and the multispeed reversible fan. I have not installed either, so my take on them is from what I've heard from others who have installed them and from hearing one of the single speed retrofit fans in a friend's RV. All the discussions I've heard indicate that they are significantly louder than Fantastic fans. For that reason, I'd consider replacing the entire vent assembly and installing a Fantastic multispeed reversible fan in its place. The vent dome that is installed on your RV should be held in place by screws around the perimeter and it sould be removeable and then reuseable with the Fantastic fan assembly. Be sure to use Dicor to seal the new vent in place and take your time cleaning the old sealant off the roof when you remove the old vent assembly. If you should happen to "nick" your rubber roof, just be sure to apply Dicor liberally over the damaged area.