The panels from pro helix reptile radiator and there is a German company I don't recall the name of all suggest a min distance of at least 15 inches and some as much as 22. RHPs are designed for arboreal set ups and animals that bask. Royal pythons are neither. Even with a 6 inch for surfaces it means very little room for a hide. When you factor that if the interior is 12 inches tall there is only 10 inches free air inside. I have been running an on going test on a RHP (almost a year now) the results are simple it is not efficient in low terrestrial enclosures. Yes it works but has lots of problems it always generates a vertical gradient top to bottom. You can choose to set the temp for the hide top or floor beside the hide or the floor under the hide. All three locations are different. It is a radiant source so direct line of sight much like the sun. When you go to the beach the sand that is out in the sun is way hot but the sand that has been in shadow all day is not. The hot side hide casts a shadow for the IR from the panel dropping the temp dramatically. The top is hotter than the bottom the outside hotter than the inside. There is no way around this. Probe placement is hard as well there should never be a situation where a snake can shadow a probe from the heat source unless it can easily move under the probe location to a lower level. Where do you place the probe? The only solution I found is to dangle it from the panel centre. It is hard to fully secure so it is ridged. Some have used a hard 90º elbow and glued this to the floor pointing up these two seem to be the best neither is good. IMO RHP do not belong in enclosures less that 16-18 inches and are best used as designed vertically. Yes they can be adapted to a horizontal situation but the additional cost and complication for what gain so the snake can bask?

A PVC floor is superior in every way to wood, UTH run heat floor to ceiling so the hottest spot is where the snake will be rather than setting the hottest spot to where the snake is not and using the coolest location of the cage to be the correct temp for the snake. Anything about this is too hot. How does this seem like a good idea? It is a solution to a problem you have not made yet the wooden enclosure floor.


I use a 2 foot fluorescent tube in a 24x30x14 enclosure with a room temp of 66º it holds 76-79ºF ambient (sole heat source) the face of the lights hit about 90-100º 60º-100º less than RHPs It heats air not objects (like RHPs) so they make a great air heater as well as lights. The blue LED electronics run about 8-10º cooler so they do well over night.

If you choose to gel a fluorescent light I would use Rosco gels they will take the heat no problem. I would still suggest LED over this.
http://www.rosco.com/filters/index.cfm