It is efficient in its use of propane, not so efficient in its use of water.
How long does it take to get warm: 10,20,30 60 seconds? Maybe you have a marginal flow rate. I dramatically improved my shower flow rate by removing a white button inside the connection of the hose to the shower head. Flow went up and time to hot water went down and total cold water also went down.
You can catch the first half gallon or so in a jug to use for dish washing later if you are really right on water.
David
__________________
|