Abstract: At least one aspect of the present invention relates to a system for heating a gas using positive temperature coefficient (PTC) elements. More particularly, aspects of the present invention are directed towards PTC element configurations and orientations. In one aspect of the present invention, PTC elements are interposed between heat sinks such that they transmit current from one heat sink to another. The PTC elements may be arranged in a radial configuration, which may have more than one PTC element per radial flange. The heat sinks may have grilles which allow air to flow perpendicular to the heat sinks and between the PTC elements.

Abstract: A method and apparatus for conditioning air includes conditioning units that are removably attached together. The conditioning units may be separated from each other and individually perform conditioning functions, such as air moving, heating, humidifying or cooling.

Abstract: A portable electrical heater including a portable housing defining an air inlet, an air outlet, and an air flow path therebetween; a blower for circulating air through the air flow path; an electrically powered heater element disposed in the air flow path; and a control board including a selector for effecting operation of the heater, and a digital display. An ambient temperature sensor and an electronic controller controls energization of the display and heater element in response to inputs from the selector and temperature sensor.