A patio heater (also called a mushroom or umbrella heater) is a radiant heating appliance for generating thermal radiation for outdoor use.

A burner on top of a pole, it burns liquefied petroleum gas (LPG), propane or butane, 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. A reflector a top the burner reflects heat that would be otherwise lost upwards. This is because the reflecting hood is usually silvered which makes it a poor absorber of heat but excellent at reflecting infra-red radiation back. This reduces the amount of heat lost by conduction as silvered surfaces will not absorb infra-red light. The chimenea is an alternative to the patio heater for home use, which burns wood instead of gas.

Some newer types of patio heaters are electrically powered radiative heaters that emit infrared energy onto nearby surfaces, which in turn heat up the surrounding air.

Other styles of outdoor patio heaters include:

Wall Mounted Patio Heater: fixed to a wall or structure making for safe operation

Hanging Patio Heater: portable and small foot print which comes in electric only

Tabletop Patio Heater: ultra portable and great for smaller groups or outdoor dining, but uses a small propane tank