There have been several reports analysing hard disk drive reliability correlated against running temperature, which reveal that running in too cold an environment is more detrimental than higher temperatures. However, for the vast majority of companies and users this will never be an issue, in fact it is much more likely that equipment will be running higher than the optimal temperature.
High temperatures are still the single biggest issue which causes failure of hardware. The mechanism of the failure is not predictable, as the build-up of heat affects components in slightly different ways, and a hot spot would be the most likely location for a failure to occur. A failure from high temperatures is also not always immediately obvious when a drive arrives for data recovery, unless a component on the controller board has burnt out.
Airflow is Essential
Even if your office or home environment is cool, without airflow the temperatures inside a computer will rise. The temperature in such cases will often not be uniform, with hot spots appearing. Computer cases will usually come with a fan along with a CPU cooling system. These may not be enough to keep air flowing across hard disk drive installed in the case, which could lead to high running temperatures.
The home environment is particularly bad for dust sources, but most office environments, especially when carpeted will have dust circulating in the air. This dust will be sucked through the case of your computer and will settle on different surfaces, particularly components such as the fan and heatsinks. This build-up of dust will, if left unchecked, lead to a reduction in the cooling efficiency, so it is essential to ensure that this does not happen. Sometimes when a computer is first booted, noises can be heard from the fans, which may suggest a build-up of dust, or another issue with the fan.
Heat Damage Builds Up
Each hard disk drive is manufactured with an operating temperature range, a fairly typical one being 5 to 55 degrees Celcius. This does not mean that a drive running outside this range will instantly fail, but the chances of a failure are severely increased. Conversely running with this temperature range does not guarantee the hard disk drive will not suffer a failure. The higher the operating temperature within the range, the more likely that damage will occur.
Heat is insidious, as any minor defects, which under normal operating conditions cause no problems, may become worse. Electrical components are particularly prone to heat damage, which in the worst cases can melt. Continually high temperatures can also affect other vital components, such as the spindle motor, causing the fluid bearing to fail, or damage the read/write head stack.
Failures Can Cascade
A simple failure such as erratic behaviour caused by a component failure on the controller board could potentially result in the spindle motor operating incorrectly, leading to vibrations which allow the read/write heads to impact with the platter surface. All hard disk drives failing as the result of heat damage should be sent for professional data recovery, as the drive will usually need to be rebuilt into order to recover all the data.