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Optimal working temperature

Level 1
Level 1

There have been a few questions regarding working temperature of kit. All are referred to the relevant data-sheet(s) which usually list a wide range of temperatures such as 0C to 40C

Is there any documentation regarding an optimal temperature range within the working range to maximise the life and performance of Cisco switching equipment?? This would allow optimal settings for aircon - possibly saving money.

I'm sure we don't all run our switching closets and racks at 40C to save on aircon! 


5 Replies 5

Reza Sharifi
Hall of Fame
Hall of Fame

Most data centers set the temperature somewhere between 65 to 70 degrees, which is about 18 to 21 Celsius.


Indeed - we do use 20/21 degrees celcius in our DCs, closets and equipment rooms. However, a customer site has asked about increasing the temperature further in order to save on aircon costs. I suppose my question really is WHY are most DCs set somwhere near 20 degrees C ?

You can defiantly use a higher temperature (probably up to 80, which is close to 26/27C) and would not harm the equipment. The problem with higher temperature is that if one of the AC units fails, you really don't have that much time to react before the temperature reach 30C or higher. You usually want to design it in a way that if one of the units fails on a weekend and you can't get someone there on time to fix it, the higher temperature does not harm the equipment.



Martin L


follow data-sheet of a product; it should specify operational temp range;  not sure if it says optimal.  I would guess the lower the better.

if the range is 0C to 40C, then keep the room within that range. 


Regards, ML
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Joseph W. Doherty
Hall of Fame
Hall of Fame
Like Martin, I believe cooler is better. Hotter, I also believe, reduces the life of electronics. So much so, that going above spec temperatures, is what causes premature hardware failure. (BTW, temperature to operational life might be on an exponential curve.)

The "ideal" temperature, for the equipment, is probably 0C, but 20C, besides being in the middle between 0C and 40C, is about just right for people too.

But to your customer's goal, something else to consider is temperature where?

Temp. specs really means inside the device, across all component electronics. Ideally, device's design insures no hot spots in the device, but something as simple as leaving an empty module slot (i.e. no cover plate) can disrupt the internal airflow. Or not having the ideal air flow to or from the device (i.e. external to device local hot spots). Running in a max temp. situation, leaves no margin for error (another advantage of staying below the max temp. operational value). (Keep in mind, if internal airflow isn't as "expected" device may not trigger a over temp alarm when some of it is over temp.)

So, with a real careful review of airflows to/from device, and device hardware configured for internal airflow, yea, you can probably push up to even the max, like 40C. Again, this leaves no room for error (or a reserve cushion, as noted by Reza), and possibly shortens the life of the equipment. (By shorten, though, if you stay within spec, you'll likely achieve the design life of the device, but perhaps not the extra 5 to 20 years some equipment remains in service beyond that. [Whether the last is a good or bad thing is a different debate - laugh.])
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