Linux machine running hot

I run several servers  for a company. Over the past couple of weeks I have noticed that one of the linux boxes was running much noisier and hotter than it normally does. I wondered initially whether this was due to the hot spell we have been having.
An inspection of the machine showed the culprit to be dust and fluff.
Switching off the machine and giving it a good vacuum removed the accumulated dust and stuff from the CPU heat sink and fan, from the graphics cards fan and from the power supply fan.
The intakes were also full of stuff. The worst machine was the highest up on the stack were the air flow is probably the greatest.
Before cleaning 20% energy usage Noisy Temp 67C
After cleaning 12% energy usage Quiet Temp 25C
It was about 3 months ago that I had cleaned the machines, so perhaps cleaning them more often will reduce the amount of electricity used and improve the performance.