What is Power Usage Effectiveness (PUE) and How Is It Measured?

If you've researched data centers and efficiency, you've certainly come across the term PUE. It stands for Power Usage Effectiveness, and is the leading metric for determining the energy efficiency of data centers. So what does it mean, in practical terms? PUE is a ratio of energy usage. You compare the total amount of power usage and the amount of that wattage that goes directly to powering computing equipment. With a PUE of 2.0 (a 2 to 1 ratio), it would mean that only half of the power coming in to the data center actually goes to the IT equipment. The rest goes to cooling, lighting, etc. The ideal, then, would be a PUE of 1.0, where every watt coming in goes directly to powering equipment. 

The average PUE for data centers in the U.S. is a little bit of a debate, but the number seems to be somewhere between 1.8 and 2.0. This, in itself, is quite an accomplishment. Just three years ago the average PUE was near 2.5. According to Data Center Knowledge large users such as Google, Yahoo, Facebook and Microsoft have reported industry-leading ratings in the 1.07 to 1.2 range.

All of Green House Data's facilities operate at a PUE between 1.25 and 1.38, meaning we fall very close to the data "giants" and industry leaders, and well below the industry average. How do we do this? In Cheyenne, we take advantage of our beautiful Wyoming climate. We can cool the data center using outside air for almost the entire year. We've also invested in the latest innovations in separating hot/cold air, and filtering the hot air out of the data center. In Portland, we also utilize naturally cool air as well as collect rainwater. In Newark, we have a vast array of solar panels that helps our energy efficiency stay high. 

What does all of this mean for the customer? Ultimately, it means lower costs to you! You can think of it like you would a high efficiency (HE) laundry unit. You can get an HE washer for around $1,500. You can get a "normal" washer for anywhere between $400-$800. The HE version is obviously a higher up-front investment, but over time, your energy costs will lower, thereby making up for that extra cost. Our data centers operate in the same way. We invest at the beginning in better and more efficient technology. Ultimately, though, we save money in the long run, and don't have to spend nearly as much precious energy on non-IT functions like cooling and lighting. We then pass those savings on to our customers.