How the calculation works
Watts are divided by 1,000 to convert them to kilowatts. That figure is multiplied by the hours used and your unit price.
Example: a 300W airer used for six hours at 25p/kWh costs about 45p.
Remember drying time
A low hourly cost does not automatically mean the lowest cost per load. Loading, room temperature, airflow and whether you use a cover can all change the time needed.