Extermination of insects by heat

A method of killing space occupying insects which are in occupancy in hidden void spaces, which void spaces are formed by a plurality of structural elements, said elements having a void space facing surface, and at least one of said elements having a living space facing surface, and said elements having dimensions of thickness and length so as to form structure around said void spaces, said insects having the inherent characteristic of susceptibility to a lethal temperture which if maintained for a necessary period of time causes the death of said insects, said method comprising:

• heating said hidden void space to said lethal temperature by the application of heated gas, and maintaining said lethal temperarure for said period of time by heating said living space facing surface and thereby heating its respective structural element to heat its respective void space facing surface, and thereby heating said hidden void space to exterminate the insects therein;
• circulating said heated gas.