Submetering Goes Mainstream

By Chuck Ross | Jun 15, 2017




Until recently, the energy standards referenced by state and municipal building codes in the United States have emphasized performance levels of products specified for lighting, air conditioning and other building systems without reference to the importance of maintaining those performance levels over time. 

Lately, though, standards developers have become more interested in giving owners and operators the information needed to ensure building systems live up to expectations on an ongoing basis. The result is a growing emphasis on submetering to provide that data—an approach electrical contractors will see more often.

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) introduced submetering as a requirement in the 2013 edition of its Standard 90.1, Energy Standard for Buildings, Except Low-Rise Residential Buildings. Though the standard was released Jan. 1, 2014, many states and municipal jurisdictions have not yet adopted it. Therefore, electrical designers and ECs might still be in the dark regarding many provisions—especially new ones, such as those in Section, dealing with energy monitoring. Measurement devices now are required to monitor the following individually: total electricity use; heating, ventilating and air conditioning systems; interior lighting; exterior lighting; and receptacle circuits.

Multitenant buildings also must provide equivalent system-level monitoring for each tenant space. The 2016 edition of ASHRAE 90.1, released Jan. 1, 2017, specifies reporting schedules for total energy use and requires this information be integrated into building management systems, where they exist.

Making meters more affordable

The new emphasis on monitoring has multiple roots. First, as experience with the U.S. Green Building Council’s Leadership in Energy and Environmental Development certification program has matured, many have noted the limitations in a snapshot approach that evaluates building efficiency at a project’s completion but neglects follow-up to ensure that reduced carbon footprint is maintained over time.

Perhaps more important, the equipment enabling submetering has become less expensive, which gives code developers more leeway in mandating its use, knowing it won’t add substantially to an owner’s bottom line.

“The real key enhancement has been the growth in economical branch-circuit monitoring capability,” said Troy Hull, director, Leviton’s measurement and verification group. “In the last five to 10 years, you’ve seen a much sought-after multi-circuit capability, and the costs have been driven down.”

Previous products could only handle a single circuit and took up valuable wall and panel space, so designers needed to ensure specific load types remained segregated into individual panels to meet such requirements previously.

Also, today’s new offerings can provide submetering capability with very little extra labor.

[SB]“The cost of installation practically vanishes when meters are specified to be provided within factory-assembled electrical distribution equipment,” said Wayne Stoppelmoor, industry standards manager for energy efficiency, Schneider Electric.


However, even the least expensive submetering products will fail to add value if facility personnel don’t put the data these devices produce to work. The first step is to establish energy-use baselines for the separately monitored loads. This information can be used for comparison in ongoing monitoring programs to catch any anomalies and plan for future improvements. Plug loads, in particular, have become more significant contributors to overall consumption, and all those desk lamps, copiers and break room/kitchen microwaves can wreak havoc on even the most efficiently designed office space if someone isn’t paying attention.

“If you look at today’s building design, lighting loads are much lower, and plug loads are much higher, proportionally [than in the past],” Hull said. “Monitoring will catch system problems it will catch laziness, and it will help to tweak performance of the building even more.”

A monitoring program could be even more valuable in an industrial facility, where electricity consumption can be orders of magnitude higher than in a commercial office or retail space. For example, automobile manufacturers could raise profit margins by implementing submetering for their paint rooms’ compressed-air equipment, which can be energy hogs. Higher-than-expected electricity use could indicate hose leaks or other issues, forcing the equipment to work harder than necessary.

Understanding what’s required

However, both the consulting engineers who specify metering equipment and the ECs who install it often still have a bit to learn about the evolving code requirements and the best means for meeting them. Additionally, because standards are adopted through state and local building codes, news that the specific edition of a referenced standard has changed doesn’t always make it through to design and installation professionals in the field.

“I think it’s a mixed bag,” Hull said, speaking of both contractors’ awareness of the new provisions and of the equipment options available to meet them. “Most contractors don’t touch metering very often; they can have a little bit of difficulty because their folks aren’t too familiar with the nuances. Not every building has had metering, but that’s changing. In the next five years, the contractors’ experience with these products will grow, just out of necessity.”

Larry Weber, vice president of Honeywell’s buildings group, agreed that many contractors are not yet aware of the energy-monitoring updates included in ASHRAE 90.1’s 2013 edition or the options for meeting them.

“I would say the trades are probably not that familiar, because that decision is being driven by the consulting engineer,” Weber said. “I’d say there’s a wide range of consulting engineers; some are very cutting-edge. It’s a very broad spectrum.”

However, even those engineers might not quite yet be up to date with the changes.

Design engineers face the challenge of keeping up with a continuing cycle of code updates.

“Manufacturers need to provide product training and show how the products can be applied to meet the code,” Stoppelmoor said. “For electrical contractors, the training also needs to include installation and any aspects of commissioning that would be in the scope of the contractor’s work.”

Contractors also can be proactive in pursuing such training on their own. Having an understanding of the new monitoring requirements when plans come into the office could help a firm become more of a partner in electrical-design decisions.

“Some electrical contractors recognize opportunities for value engineering and will work with the consulting engineer to approve a deviation from the design,” Stoppelmoor said. “Design/build contractors are the most familiar with the code and equipment options because the engineering process and decisions are internal.”

More metering to come

Submetering seems likely to become even more prevalent in the national energy codes. Some foresee an increased push for integrating submetering data into larger building management systems, as indicated by the 2016 updates to ASHRAE 90.1.

Weber said that, upon asking how facilities are using their data, he often finds their meters are not connected to anything.

Because submetering data isn’t integrated into the overall building control system, facility personnel are recording the information by hand.

“Building management systems provide a better experience, and I think you’ll see a greater need for that compatibility,” Weber said.

Submetering could become a vital tool for enabling building operations to become more responsive to their real-time impact on the connected grid. Electricity rate structures could shift to encourage ongoing efficiency improvements, the way many utilities incentivize the ability to reduce demand during peak periods.

“What’s next is, now let’s put the onus on the individual building to demonstrate their efficiency, year-over-year,” Weber said. “I see ASHRAE 90.1 pushing buildings to that level of technology.”

About The Author

ROSS has covered building and energy technologies and electric-utility business issues for more than 25 years. Contact him at [email protected].






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