Sterra Water Purifier is a smart device designed to be energy-friendly. It will go into standby mode when not in use. The electricity consumed during this mode is insignificant, at around $0.8/month.
The power needed for the hot water function is actually less than the power used to boil water with a kettle. The power required for using the chilled water function is equivalent to when you are using a ceiling fan.
Here are sample figures:
Heating: 2600 Watt - equivalent to a steam iron, electric stove
Cooling: 0.3 Ampere or 70 Watt, or equivalent to a ceiling fan