The present invention relates to an environmental control system and to a method of environmental control and in particular to a control system which provides feed back control of temperature and humidity and a method of controlling temperature and humidity.  The system and the method are each particularly useful for providing an individual with comfortable sleeping conditions. 
In order to offer comfortable sleeping conditions, it is a common practice to warm a sleeper by means of an electric blanket, an electric under blanket, or a foot warmer.  An alternate method of warming and cooling a bedroom is with the use of an air conditioner.  However, this practice does not provide for temperature and humidity control on the surface of a mattress.