Everything looks like a nail, a truism that ASHRAE (The American Society of Heating, Refrigerating and Air-Conditioning Engineers) has just demonstrated in its advice to data center operators on how to achieve greater cooling efficiency in the data center (see ASHRAE Standard 90.1). In ASHRAE's opinion, the way to achieve data center cooling efficiency is through the use of various economizer techniques (air-side, water-side …) to reduce the amount of energy used by the cooling plant. Unfortunately, this is a rather narrow view of the problem, focused on the stuff that ASHRAE members do best, i.e. air-conditioning and chilled water plants. The ASHRAE standard has now drawn a universal thumbs down from some of the largest data center operators (Google, Microsoft, Amazon, Digital Realty Trust, DuPont Fabros Technology and Nokia) who issued a joint statement urging ASHRAE to re-think it's position.