How to Choose an Infrared Lamp Heater

Infrared lamp heaters emit electromagnetic radiation in the visible light, near infrared and far infrared ranges that are absorbed by objects or people in their path, heating them without loss of energy. Their use is an economical way of providing clean and efficient heating for a large variety of applications. Infrared lamps come in a wide range of sizes and outputs. Choosing the right type of infrared heater for your needs depends on the amount and intensity of heat you want to apply, as well as the size of the area to be heated.

Most halogen lamps consist of a satin milky-white quartz glass tube or clear quartz with a filament of tungsten wire in the form of a thin coil of iron-chromium-aluminum alloy sealed within it. The tube is then filled with inert gases such as nitrogen and argon and sealed to protect the filament from contamination. A halogen compound such as bromine, chlorine or iodine is added to the inert gas mixture to extend the filament’s operational life.

Tungsten coils need special care to ensure durability. They are exposed to high temperatures when the lamp is lit and can be damaged if they become too hot. To prevent this, the tungsten is deoxidized before being used to form a double coil filament by boiling it in a solution of 10% NaOH or 50% HF (Hydrofluoric Acid) at around 3,492 °F (1,600 °C). After removal from the crucible, the tungsten is subject to secondary recrystallization in hydrogen. This process can cause distortion of the coil unless it is heat treated afterward to re-form it.

The molybdenum foil used for sealing the lamp also oxidizes on exposure to high temperatures and expands if it becomes too hot, reducing the lamp’s service life. To overcome this problem, the crucible is sometimes filled with carbon that is 1/2 the mole of carbon in methylene bromide. This is a hazardous material to handle and should be avoided, but it works effectively as a getter of residual oxygen in the lamp that can otherwise reduce its service life.

The lamp heater’s wattage determines the intensity of its heating power. Higher wattage lamps provide more intense and direct heating for applications where the radiated warmth has to travel over a short distance and reach its target quickly, such as outdoor patio heaters or curing and drying paint. Conversely, long wave IR heaters have lower output but are better at gradual and sustained gentle warming over a larger area. Both types are effective in windy conditions as their radiated warmth is less affected by atmospheric interference. For optimum efficiency, they should be used in conjunction with a suitable filter to remove the emitted visible light. This will allow the full effect of the infrared to be realized. Infrared heaters are also available with an inbuilt fan to increase their cooling capability for longer operating times and higher wattages.