Earth heat

Some confusion exists with regard to the terminology of heat pumps and the use of the term "geothermal". "Geothermal" derives from the Greek and means "Earth heat" - which geologists and many laymen understand as describing hot rocks, volcanic activity or heat derived from deep within the earth. Though some confusion arises when the term "geothermal" is also used to apply to temperatures within the first 100 metres of the surface, this is "Earth heat" all the same, though it is largely influenced by stored energy from the sun.