I did a lot of research before I invested in a RHP. I would definitely suggest at least looking into it. It might not be right for your conditions, but its worth a look.
I just didn't think I could get a PVC enclosure up to 88-90 on the hot side with heat tape alone because my house runs 68 in winter and 72 in summer. It worked in a small tub, but when I went to a medium sized tub, I had to add a CHE to get the ambient up enough. With the larger enclosure size and having to go through the PVC it just wouldn't have gotten there on heat tape alone. I figured since I was going to have to do overhead heat anyway, I may as well take the plunge. It was RHP or a hole in the top for a CHE. The RHP was more expensive, but does a MUCH better job. It gives me a perfect 88-89 hot side and 80-81 cool side, and Astrid is getting good heat without the heat tape, even inside her hide.