The present invention relates to a portable clothes dryer. In particular an external dryer cover which is impervious to air. The impervious cover encompasses an inflatable shaped bladder which is not impervious to air. Heated air can permeate the internal bladder and any garments placed on the inner bladder. With the cover in place air is not immediately lost to the atmosphere, instead the heated air temporarily retained by the external cover. The advantage of the invention is hot air is recycled and not wasted. It reduces heat loss, improves drying times and energy efficiency. The extremal cover has one or more venting apertures.