if we assume it costs 20p to dry a load off washing is it really worth hanging it out taking perhaps 15mins out off your day to do soSurely you don't use a tumble dryer in the summer?
if you take the cost off a rotary dryer at about £30 thats about 150 uses to pay for its self
i we assume half my 30ish washes a year would use the airer thats 10 years to break even
yes off course the tumble will wear out quicker but as they last perhaps 8-12 years not to bothered about that bit