I have a 55,000 BTU propane forced air heater that I am using to warm
up my detached uninsulated, and somewhat drafty 2.5 car garage. I open
a window to ensure that carbon monoxide does not build up.

My question is about safe placement of the propane tank which is
fueling the heater. I know propane is a heavy gas that sinks and
pools. Safety guidelines say not to bring the propane tank into the
area you are heating. The hose that came with the heater is 10' long.
I need another 5' or 10' to position the heater where I want it and
have the tank placed outdoors. Is adding an extension or replacing the
10' hose with a longer hose going to be detrimental the performance of
the heater?

Or, am I OK bringing the tank in the garage as long as I've tested to
ensure there are no propane leaks at the tank and heater?

Any ideas/experience would be appreciated.