Lamp Rule of Thumb

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EATON Technology Solutions


It's a great question! 

Should I turn my projector off when I finish using it? Or, should I leave it on and wait until the end of the day to shut it down?

What's better for the lamp? What will give my projector lamp the longest possible life?

Well, the answer is really quite simple. It depends on how long it is going to be before you will need it again.

Here's my tried and true RULE OF THUMB:

Ask yourself, "Will I use the projector again in the next 30 minutes?"

If the answer is, "YES", then LEAVE IT ON. 

If you like, you can blank the picture by pressing the "AV Mute" or "Blank" button. 

Different projector manufacturers call it different things.

If the answer is "NO"…because you are leaving the room, going to lunch,

or simply not going to use it…TURN IT OFF.

So, to recap…Using in the next 30 minutes?  YES = LEAVE IT ON.  NO = TURN IT OFF.

Any Questions?  Shoot me an email.


For those of you who would like a more in depth explanation, here ya' go!

Projector lamp life is determined by several factors, but the most impactful are (in order of importance):

  1. Total number of hours
  2. Total number of on/off cycles
  3. Temperature/Airflow*
  4. Power consistency**


Typically, a lamp is rated to last 2,000 or 3,000 hours.  It varies somewhat from model to model, but most fall in this range.  If a lamp goes its full number of rated hours, the projector will literally shut down and demand a new lamp.   Most lamps last the full number of rated hours.  The projector is keeping track with a built-in timer. Keep in mind lamps do occasionally blow before they reach their full number of rated hours.


Here's where things get tricky.  Every time you turn a projector lamp on, you shorten the life of the lamp.  We know this because we've kept track of this for years.  The average number of times a lamp can be cycled on and off before it blows is somewhere around 1,000 cycles.  This is not an exact science, but we can document this phenomenon because some models track both hours and on/off cycles.


The trick is to try to average 2 hours per on/off cycle (if you have a 2,000 hour lamp) and 3 hours per on/off cycle (if you have a 3,000 hour lamp). This will insure you get the most possible out of your lamp. It is not practical to use a stop watch and try to monitor this, of course.  The 30 minute "rule of thumb" I proposed above seems to work out nicely.  If a teacher with a permanently installed projectors uses it all day long, he/she will likely have 2 or 3 times each day when the projector is not needed for at least 30 minutes.  That means the lamp will be cycled 3 or 4 times each day for an average of around 2 hours per cycle.

*If your projector has a filter, it should be cleaned twice a year. More on this another time.

**Power fluctuations or outages may not do immediately detectible damage, but, over time, they are not good for lamp life.