Outdoor heating allows people to stay in substantially unenclosed spaces, when it would otherwise be too cold to do so. To this end, various outdoor heating appliances are available, including gas patio heater

Patio heater

A patio heater is an appliance for generating radiant heat for outdoor use.A burner on top of a post, burns LPG or propane, and directs the flames against a perforated metal screen. Heat is radiated from the surface of the screen in a circular pattern around the appliance...

s, quartz or ceramic electric lamps, and wood burning chimenea

Chimenea

A chimenea is a freestanding front-loading fireplace or oven with a bulbous body and usually a vertical smoke vent or chimney.-History:Originally, all clay open fire garden heaters imported to the U.S. from Mexico were known as chimeneas...

 and fire pits.

In an outdoor environment, convection

Convection

Convection is the movement of molecules within fluids and rheids. It cannot take place in solids, since neither bulk current flows nor significant diffusion can take place in solids....

 would quickly carry away heat in the form of hot air, so all these methods emit various amounts of their total output as radiant heat

Radiant heating

Radiant heating is a technology for heating indoor and outdoor areas. Heating by radiant energy is observed everyday, the warmth of the sunshine being probably the most commonly observed example. Radiant heating as a technology is typically more narrowly defined...

. Radiant heat is emitted from the appliance, and is absorbed by objects and people, raising their temperature.