Last month we covered the commercial launch of Panoramic Power, an Israeli startup that taps a building’s power circuits for real-time energy feedback. On Tuesday, it revealed its first U.S. partner: Washington, D.C.-based AtSite, which is adding Panoramic’s clip-on, self-powered wireless nodes to buildings including the U.S. Green Building Council’s headquarters.

It’s an interesting partnership for the startup, which has raised $6 million so far from investors including Israel Cleantech Ventures, Greylock Partners and Qualcomm Ventures. AtSite provides a variety of energy and resource consulting services for about 40 customers of varying sizes, including the Adventist HealthCare hospital chain.

The 19-year-old company also works with building energy technology providers like lighting control startup Redwood Systems, building software vendor SkyFoundry and Honeywell’s Tridium building management platform.

But Panoramic’s sensors, which harvest power from the circuits they’re monitoring to wirelessly transmit their readings on a minute-by-minute basis, could give AtSite’s clients a level of detail of building energy mapping that’s usually too expensive for most building owners to implement, Davor Kapelina, AtSite’s CEO and president, said.

Panoramic has been able to achieve paybacks of less than a year in most cases, added Adi Shamir, company co-founder and CEO. The returns come not just from lower energy bills, but also from operations and maintenance benefits that stem from knowing when systems aren’t running within spec, or are getting close to failure, he noted. Panoramic also builds the software-as-a-service platform to run the systems, and performs analytics to drive decision making.

Panoramic is far from the only company working on networking buildings for energy sensing, of course. At the larger scale, big commercial and industrial clients are increasingly sub-metering their building systems for greater energy awareness, usually linked into a building management system from the likes of Honeywell, Johnson Controls, Siemens and Schneider Electric, to name a few giants in the field.

But AtSite’s work with Panoramic, ongoing for the past few months, also includes facilities like supermarkets, chain restaurants and retail stores. Those small to mid-size buildings are hard to tackle with more expensive building management systems, but they also represent a fertile field for energy efficiency gains if the upfront costs can be contained.

Some startups aiming their sights at that market include San Diego, Calif.-based Advanced Telemetry, which provides HVAC controls for fast-food chains including some McDonalds restaurants, as well as home energy management in partnership with General Electric. Austin,Texas-based Incenergy provides energy management software to both utility-sponsored residential deployments and to commercial customers. And Newton, Mass.-based Powerhouse Dynamics has raised about $4.4 million to shift its focus from home energy management to retail chains.