Yes you can.
General speaking, temperature reduce 2 ℃ per hour on average.
Haier water heater use polyethylene foam insulation material and technology, have excellent insulation function.
Please set temperature on max 75℃, you would get hot water even though after one night.
Of cause, if you require more hot water in the morning, you may keep it power on all night, or select Timer function in digital model.