Adding a Hydronic system (that is what a Aqua Hot system is called), is NOT very cost efficient to a RV that does not have one. You HAVE to have a Diesel, there are LP systems, but Diesel is more cost efficient. You have to run the Zone radiator water lines thru-out the RV, and run the Diesel lines and find a place to mount the unit. IF you have slide rooms, then running the Radiator water lines is a lot more difficult and expensive. This is NOT a DYI type job. The cost just for the system(no labor) can run anywhere from $6000 to $12000 depending on the system and size of RV. Then you have the labor and the misc parts (water lines and fittings and such). It is a very nice system to have. Doug