Look for the wattage of the appliance; eg ‘300W’

Multiply that by the running hours

eg 300W x 5 hours a day x 30 days = 45 000Wh

There are 1000W in a kilowatt (kW)

So divide 45 000W ÷ 1000 = 45 kWh

In NSW the GHG emissions factor for mains  electricity is 1.0614kg CO2 per kWh

So GHG emissions of running a 300W appliance 5 hours a day for a month are 45 x 1.0614 = 47.76kg CO2