How much electricity does an atmospheric water generator use?

There is no useful single wattage answer for every AWG. The better measure is how much electrical energy the system consumes for each liter or gallon of water it actually produces.

Why the number changes

Active systems need energy to move air and cool surfaces below the dew point. When conditions are favorable, more water can condense for a given amount of operation. Poor conditions can reduce output while the equipment still consumes power.

Use kWh per liter or gallon

Specific energy consumption lets you compare output and electricity together. Published research has reported substantial variation across operating conditions and system types, which is why a DIY build should be measured rather than assigned a universal cost.

How to test your own project

Use a plug in energy meter where appropriate, record operating hours, and measure collected water over the same period. Divide energy consumed by water produced. Repeat the test as weather changes.

Also read humidity requirements and realistic output.