I have an 81 gallon water heater set at 130°.
I NEVER give out personal data like that on the net!How hot is the hot water in your home?
As previously stated 120° is the minimum temperature to prevent legionella. I keep mine at 130° to be safe. Legionella is nothing to mess with!
Sounds stupid but I believe some heat is lost through the cold pipes as they absorb heat from the water.