The Differences Between Blue Flame, Infrared & Red Flame Propane Heaters

Propane space heaters have color-associations that relate to the flame or the heating element. Infrared and blue flame units are typically used indoors while red flame units are used outdoors. They are attached to propane cylinder tanks to fuel the appliance so that it can produce heat. Infrared, blue and red flame propane heaters are portable and vent-free, so you do not have to attach them to a ventilation device such as a chimney.

Portable heaters are attached to propane tanks for fuel.

Blue Flame

Blue flame heaters provide greater heat distribution than infrared and red flame space heaters. Instead of only heating the space near the heater, they draw cold air from the floor, warm the air and then circulate the warm air throughout the room. The heated air is vented upward through a top opening in the heater. Blue flame heaters also have a glass covering in front of the unit which makes them a bit safer than other types. This prevents items from reaching the flame and accidental burns to passersby. Blue flame heaters represent the latest in space heater technology and modern designs. There are even blue flame heaters that look like fireplaces, complete with mantle-looking surrounds and artificial logs.


Infrared propane heaters use radiant and convection heat principles to warm whatever is close to the heater. The heaters are connected to propane cylinder tanks for fuel. They are also referred to as "brick" heaters because the red heating element looks like a fired brick inside a furnace. The body of the heater is often made of a heat-tolerant ceramic material. The brick panel is right above the propane gas burner. The brick panel glows bright red-orange when the propane gas is ignited. Units have a screen-like metal barrier guard in front of the brick panel. These types of heaters have been popular in Europe for years and are now popular in the United States for space heating without the need for pipe or duct ventilation.

Red Flame

Red flame heaters are used outdoors for heating patios, construction sites and open air settings such as warehouses and garages. They are often round and emit red flames around the circumference area. A propane cylinder is attached to fuel lines that connect to a burner inside the heater. When the burner is lit, the heater produces its classic red flame. These heaters generate anywhere from 4,000 to 8,000 British Thermal Units of heat energy and use catalytic combustion principles. As a result, they emit gaseous byproducts and smoke particles into the atmosphere. This is why red flame heaters are only appropriate to use outdoors or in rooms that are well-ventilated.


Blue flame and infrared space heaters can also mount them to walls. This makes them convenient for use in mobile homes where space is at a premium and keeps them off the floor so they're harder for children and pets to reach. It is important to have any type of propane heater inspected periodically to make sure that the valves, burners and heating elements are working properly. If the flame color changes to yellow or orange, disconnect the heater, stop using it and have it inspected by a propane heater technician.