Drying clothes costs nothing if you use the sun, but this isn't always an option. A clotheshorse can be used in a spare room or near a heater. Avoid using a heater just for drying clothes. When you do use a clothes dryer:
consider using the fan only
set the temperature no hotter than warm
keep the vent free of lint and clean the filter after each load
switch the dryer off as soon as the clothes feel dry – never overload or underload the dryer.