It helps to understand what a regulator does. A regulator converts a flow of high-pressure gas from your propane
cylinder and into a low pressure flow, low pressure enough that you can put your thumb over the open end of a gas line and seal it off.
Gas appliances require low-pressure propane because it's easier (and cheaper) to properly control a low pressure jet of propane and mix it with atmospheric oxygen
, allowing it to burn efficiently without creating poisonous carbon monoxide. A standard regulator -- which is what our appliances are designed for -- does a fine job of reducing propane pressure down to this level.
There are applications where a more precisely regulated gas pressure is required. Bubbling filtered propane into a organic chemistry reactor vessel at a very precise rate comes to mind. (Lynne, darn it, would probably get nervous if I started playing with exotic chemicals in the trailer.
) Since most of us, however, use propane to fuel low-tech appliances and aren't into doing organic chemistry science experiments in our trailers, <strike>I think the standard regulator will do just fine</strike>.
IMPORTANT NOTE: Please read my post a little further down. After doing some research I found a reason why a two-stage regulator is a good idea.