hot water heater
The extra hot.
Use water heater. The device heats water. Hot-water heater is the same padding with a hyphen. The phrase is common. It is idle.
Examples
Use The water heater failed.
Avoid The hot water heater failed.
The extra hot.
Use water heater. The device heats water. Hot-water heater is the same padding with a hyphen. The phrase is common. It is idle.
Use The water heater failed.
Avoid The hot water heater failed.