Heating by radiant energy is observed every day, the warmth of the sunshine being the most commonly observed example. Radiant heating is a technology for heating indoor and outdoor areas. For snow melt applications see: Snowmelt system. For high temperature indoor or outdoor radiant heating, see: Infrared heater. Moderate temperature radiant heating and cooling is usually composed of relatively large surfaces that are internally heated or cooled using hydronic or electrical sources. This article mainly addresses radiant heating and cooling with moderate source temperatures, used to heat or cool indoor environments. Within this category, it is practical to distinguish between high temperature radiant heating (devices with emitting source temperature >≈300 ☏), and radiant heating or cooling with more moderate source temperatures. According to some definitions, a technology is only included in this category if radiation comprises more than 50% of its heat exchange with the environment therefore technologies such as radiators and chilled beams (which may also involve radiation heat transfer) are usually not considered radiant heating or cooling. There are many subcategories of radiant heating and cooling, including: "radiant ceiling panels", "embedded surface systems", "thermally active building systems", and infrared heaters. Radiant heating and cooling is a category of HVAC technologies that exchange heat by both convection and radiation with the environments they are designed to heat or cool. Systems using temperature-controlled surfaces to exchange heat with their surrounding environment through convection and radiation