Reducing Data Center Cost with an Air-Side Economizer

At a time when more data centers than ever before are calling into question the necessity of mechanical cooling and whether there exist other, better methods of cooling. Some data centers, like QuadraNet, are implementing air-side economizers, which synchronize outside temperatures with inside data center temperatures. These tools aren’t permanent solutions, since ASHRAE recommended operating ranges are between 18C and 27C (65F and 81F), which means that on a particularly hot day, it may be 90F+ outside, and it would obviously not be beneficial to turn an air-side economizer on. While newer hardware is built to higher standards and is better able to withstand higher temperatures, older hardware can be extremely prone to failure at temperatures above ASHRAE’s recommended operating range. Since a large percentage of data centers built for public use still use some legacy hardware, it seems that mechanical cooling is here to stay, at least for the foreseeable future.


  • An air-side economizer brings outside air into a building and distributes it to the servers. Instead of being re-circulated and cooled, the exhaust air from the servers is simply directed outside. If the outside air is particularly cold, the economizer may mix it with the exhaust air so its temperature and humidity fall within the desired range for the equipment.
  • The air-side economizer is integrated into a central air handling system with ducting for both intake and exhaust; its filters reduce the amount of particulate matter, or contaminants, that are brought into the data center.
  • Because data centers must be cooled 24/7, 365 days per year, air-side economizers may even make sense in hot climates, where they can take advantage of cooler evening or winter air temperatures.

Did you know?

  • Intel IT conducted a proof-of-concept test that used an air-side economizer to cool servers with 100% outside air at temperatures of up to 90°F. Intel estimates that a 500kW facility will save $144,000 annually and that a 10MW facility will save $2.87 million annually. Also, the company found no significant difference between failure rates using outside air and an HVAC system.