Projectors lamps

Projectors lamps are among the very few parts in a projector that can be replaced. Even so, there can be problems sometimes when the projector lamp is very specific to a model and not generally available.

Lamp life

Total Lamp Life is the expected number of hours any given lamp will work before it needs replacement. This should not be taken as the minimum number of hours because other factors can easily influence this number. LCD projectors typically use metal halide as a source of light and the expected lamp life is between 750-4000 hours. The term lamp life is a bit ambiguous because projector lamps dim gradually and technically speaking they are still function even when they are working at half their original intensity. This is why manufacturers ignore total lamp life and they prefer the term Peak Lamp Life. This value represents the number of hours within which the lamp will work at a minimum of 80% brightness. Some manufacturers might even hold 90% brightness to be the minimum acceptable value for peak lamp life.

Dimness

Projector lamps will last longer if the projector is mostly used in "economy mode" and operates in a dust free environment. Frequent power downs are essential to a longer lamp life. Those projectors that are used continuously for long periods of time will be the first to require lamp replacements and the lamps will not last as long as their peak lamp life. 
 
If you notice that you have to keep adjusting the brightness and contrast but are still unable to maintain consistent image then it might be that the projector lamp is going dim. Some projector models come with inbuilt sensors to inform you of the lamp usage but direct visual confirmation is always sufficient to know when you need to replace the projector lamp.

Operating time

Projector lamps are just high-tech light bulbs and like all such devices they have a limited operating time. This time is calculated in hours and is called the lamp life. There are some new models that claim to have a lamp life of more than 4000 hours, which was once considered an unbeatable high figure. Most lamps will function for their specified lamp life though some might fail due to minor unavoidable defects. It is recommended that a projector should not be used for more than 3-4 hours per day and then only in a clean, dust and vibration free environment. If the projector is used for longer durations or in unclean environments where there is a danger of contaminants then operating time will quite likely go down. The more number of hours per day a projector is used, the shorter will its operating time be.

Increasing lamp life

The reason for recommending a 3-4 hour operating schedule is to ensure that the projector does not overheat. Metal halide and halogen lamps can get very hot and this heat is damaging. Even when using the projector for only 3-4 hours each day you must give it frequent breaks to cool down. Overheating is one of the biggest reasons for unexpected lamp failure. If the projector can display its temperature on its interface then nothing like it. A reading can be taken directly from there and temperature can be kept control. If you do not have such a visual aid then you can estimate and shut down the projector every 30 minutes for 2-3 minutes. If you are not operating out of an air-conditioned environment then the room is more likely to be subjected to dust particles and other contaminants. Ensure that the projector has a relatively dust free environment to work in and is not subject to harmful vibrations. 
 
Whenever possible, keep the projector running in "economy mode" as this is the optimal running mode for all projectors. The power mode may be used once in a while but should not become the default setting. 

UHP

Ultra High Performance, or UHP, is a propriety design using a metal halide lamp that is manufactured by Philips. The primary advantage is more brightness at lower power consumption. This results in a lighter and smaller projector as the power supply and cooling unit are both shrunk. Since the lamp works on low wattage, it generates less heat and consequently has a longer operating time.