The appliance in your home that doubles your electricity bill. It consumes as much in a minute as others do in hours.
There are some mistakes that lead to inflated bills that people make without realizing. For example, appliances left plugged in, even when not in use, consume electricity, as do laptop chargers that are not in use.
One appliance that can double the bill is even the bathroom fan. Generally, older blocks have a bathroom window to help with ventilation, but for newer ones, developers usually opt for a fan.