Fans, Part of the HVAC System of a Houston Data Center
![Many large fans under grates, facing up, in metal boxes, part of the HVAC system of a large building.](/photos/u/2e4c13944ba8aa247b5be01717cc5b35-640.jpg)
Taken on Jun. 19, 2012
The fans here are part of the HVAC system of a Houston data center. Websites and other online services use electricity both directly through computers, and indirectly through climate control systems essential to their operation.