The move represents a second step for the service provider with $100 billion in annual revenues. In January it mandated any replacement equipment should show a 20 percent gain in power efficiency.

Verizon published a technical paper on its requirements, specifying use of computational fluid dynamic simulations. The news was formally announced at the carrier's fifteenth annual conference for systems suppliers attended by about 300 people from 75 companies.

"We started this effort informally back in July, meeting with about 35 OEMs who read our spec and gave us feedback on it," said Chuck Graff, Verizon director of corporate network and technology. "We think a lot of people are doing this [thermal modeling] already but not always making changes to airflow and board placement based on their results," he said.

Verizon has rejected some systems so far for not showing 20 percent power efficiency gains. However, it has also agreed to buy two or three systems that failed to meet the requirement.

"A lot of it had to do with where the OEM was in its design cycle," said Graff. "We don't want to stop progress on the network," he added.

Verizon will establish baseline benchmarks for new systems supporting emerging technologies such as LTE or high-speed Ethernet.

"Overall, we've been very aggressive," said Graff. "We've realized a 3,000-pound reduction in carbon emissions and a $2.2 million savings so far," he said.

Separately, Verizon has an ongoing pilot project testing the use of sensor networks and software from Marine Inc. to monitor energy use and heat in its data centers.

On Tuesday, startup Arch Rock announced an upgraded version of its wireless sensor network for data centers that monitors both power use and heat. The offering is an alternative to embedded sensing capabilities that data center power, heating and cooling equipment vendors have been building into products for some time.

"Wireless sensors have been used in the data center for a while, but they are somewhat siloed," said Roland Acra, chief executive of Arch Rock.

The Arch Rock system uses an Internet protocol based wireless net, compared to proprietary networks on many offerings. Legacy ModBus and BACnet interfaces are also widely used for such systems, he said.