by Parsa T. Zadeh, DDS
Ever since personal computers became common- place in dental offices, the computer industry has been advising dentists to leave their systems on overnight and on weekends. Their reasoning was that every time a computer is powered up, the electrical surge through the system causes more wear and tear on the electronics of the computer than the constant current that would pass through hours on end when the computer is not in use at nights and on weekends.
That recommendation never sat well with me. The current trend to have a workstation in each operatory, thus raising power costs, in addition to my personal experience with more than a dozen computers in my office, has made it even more compelling, in my opinion, not to follow that advice. Here is my raison d'être.
A typical dental office is open nine hours a day for five days each week. A typical workstation's power consumption is 200 watts per hour (100 watts for the PC plus 100 watts for the monitor, even in screen-saver mode). Leaving a single workstation "on" all the time — as opposed to turning it on in the morning and turning it off at night — results in 24,800 watts per hour extra power consumption per week. That translates into 1,289.6 kilowatts per year. At 14 cents per kilowatt, it comes to an extra $180.54 per computer per year. Take the number of your workstations and calculate for yourself your power savings per year.
What about the "surge" that we cause when we turn the computers on in the morning? My Windows-based computers crash/freeze a few times every day, and then I have to reboot (turn the computer off and back on) to get them going. That does not seem to be of any concern to the computer experts. In fact, whenever a problem arises and you call tech support, the first thing they suggest is the "blessed" reboot. Besides, have you noticed how many times they turn your computer on and off when they are installing hardware or software? The most ironic statement I've heard is to leave the system on overnight to "protect" it, but to clear the memory of various programs and to speed things up, reboot the system when you start work the next morning! Let's assume that the extra power consumption was not an issue. After all, we are rich dentists and can afford to throw away a grand or two.
Let's also assume leaving the computers on at night and rebooting in the morning left us even on the "surge score." Leaving your computer on about four times longer than you need it reduces its life by 75 percent. My experience with PCs has shown that under normal use, the first thing that "wears" or "burns out" is the CPU fan, followed by the power supply. Each of these items, like any other mechanical thing, has a certain limited lifespan.
If you leave your PC on all the time, you are more likely to burn or wear these parts out before it is time to get new computers. I also would like to note that all that dust collecting inside the case is proportional to the time that the fan is running. Leaving a computer running 24 hours a day, seven days a week, year after year, you begin to wonder whether the "mid-tower" is a computer case or an upright vacuum cleaner! I have had to replace a number of internal tape drives and floppy drives that were not frequently used and simply jammed (with dust) during my gullible years.
Perhaps Detroit should suggest that cranking the cold engines on a car causes excessive force on the engine components and, thus, the engine is best maintained if the car is left running all the time! Then they should make arrangements to run a "gasoline line" along the gas pipes to your garage. Your car hooks up to the gas line as it pulls into the garage. Forget about going to the gas station; the gas company fills your car up daily at your own home and bills you monthly. Of course, your phone will be busier than ever. While you are telling the Sprint person that you are happy with AT&T and not interested in changing telephone service, the Exxon rep comes on the line to offer you 10 free gallons of premium unleaded gasoline to be used in any vehicle of your choice, if you switch from Chevron. We are talking about the "golden years" for mechanics and the oil industry here!
As you can see, leaving your PC on continuously when not in use is as brilliant an idea as having your car engine running when it's parked at night.
Parsa T. Zedah, DDS, graduated with honors from the College of Dental Surgery, Manipal, India, in 1984. He completed a one-year general practice residency in 1985 and has been in full-time practice in Beverly Hills since 1988. His practice focuses on cosmetic and full-mouth rehabilitation. He also is a lecturer at the University of Southern California Dental School in the Department of Restorative Dentistry. His dental office is totally paperless, statementless, and insurance-free. He can be reached by phone at (310) 273-9919 and by fax at (310) 273-3319.