Measuring, Verifying, and Displaying Building Energy Data

By Jessica Boehland, Alex Wilson, and Allyson Wendt
Reprinted by permission from BuildingGreen.com

Andy Shapiro noticed something funny when he examined the energy use of the new manufacturing facility for NRG Systems, Inc., in Hinesburg, Vermont: lights were turning on at night when nobody was using the space. The LEED^® Gold building’s sophisticated measurement and verification (M&V) system, which records when and where the building uses energy, allowed Shapiro, principal of Energy Balance, Inc., in Montpelier, Vermont, to see the unexpected blip of energy use and to solve the mystery. The culprit was neither a ghost nor a system malfunction, but Otis, the company cat, who was tripping the occupancy sensors during his midnight prowls. A simple adjustment to the system’s sensitivity reduced the building’s energy use and allowed Otis to continue his adventures in the dark.

What is M&V?

M&V is the capability to track the performance of a piece of equipment, a mechanical system, or an entire building. Ideally, this tracking allows for adjustments that reduce resource use and operating costs. M&V is most often used to track energy consumption, but it can also be applied to water use, indoor environmental quality, and a range of other metrics. M&V simply allows a user to compare the performance of a particular system or building to the performance of the same system or building at an earlier time, to the performance predicted by a simulation, or to the performance of other systems or buildings.

The green design community, however, is learning that in addition to its role in verifying savings, M&V can also be employed as a more direct means of reducing energy use. Monitoring energy systems can identify problems that might otherwise have gone unnoticed as well as opportunities for greater efficiency even when systems are operating as intended. Combined with dashboard systems, which display real-time energy use information, M&V can provide feedback to building occupants, leading to behavioral changes and energy savings. “Feedback is part of nature,” says Bill Reed, AIA, of the Integrative Design Collaborative in Arlington, Massachusetts. “Systems respond to external stimuli. M&V is bringing us closer to the way nature works.”

In 2006 and 2007, researchers at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington, decided to test whether this feedback loop could help homeowners save energy and money. They provided 112 homeowners on the Olympic Peninsula with advanced digital controls on their heating systems, water heaters, and clothes washers. Through an online interface, the homeowners could set their sensitivity to electricity prices (which varied according to peak utility periods) and their level of tolerance for fluctuating temperatures and other inconveniences that may occur from reducing electricity use during peak periods. Their electricity use was then adjusted automatically.

Participants in this GridWise demonstration project reduced their electricity bills by about 10%, and the utility company determined that, based on the customer response in this demonstration, if implemented utility-wide the technology would result in a 15% reduction in peak loads—measuring and displaying the energy information worked.

M&V’s Role in the Design and Operation Process

M&V planning, which includes building owners and operators, should begin in the earliest phases of design. HVAC system design may change in response to the desire to measure building performance. Actual measurement, however, begins during commissioning, the process of ensuring that the building’s systems are functioning properly. “What the M&V plan does in the short term is validate whether the commissioning was done correctly or not,” says Taylor. Reed echoes that thought: “We model, we commission what we model, and then we verify what we commission.” As the building ages, however, the role of M&V diverges from that of commissioning. Commissioning can tell if a boiler was installed according to the manufacturer’s recommendations, but it can’t tell whether that boiler is running longer than necessary or how adjusting the temperature setbacks will affect the efficiency of the entire building. “M&V is the only way to review for continuous improvement,” says Thomas Taylor, general manager of Vertegy, a subsidiary of Alberici Corporation, which used M&V in its headquarters in Overland, Missouri.

M&V also shares some territory with post-occupancy evaluation (POE), which sometimes includes M&V information but is generally broader in scope, considering the qualitative aspects of a building’s performance—such as whether occupants are happy with the temperature or the quality of the light—as well as the quantitative aspects—such as the average temperature or amount of light. POE also differs from M&V in that it represents an isolated snapshot of a building’s performance, whereas M&V involves regular, long-term analysis.

The M&V Plan

The owners’ goals should drive the M&V plan. Based on those goals, the project team can “formulate how you collect information, when you collect information, and what you use it for,” says Taylor. In practical terms, the M&V plan should specify which systems are to be monitored and how. In addressing the building’s lighting system, for example, NRG Systems’ M&V plan specifies, “Lighting is fed from four dedicated breaker panels. Each panel has a watt transducer, and data is tabulated by the DDC (direct digital control for building automation) system.”

The plan should also explain how the M&V information should be used. NRG’s plan calls for rerunning the energy model for the building, as it was built, following the first year of occupancy, with inputs adjusted to match actual set points and occupancy. It also calls for using the adjusted inputs to model the baseline building, an inexpensive process that allows for a more accurate estimation of the building’s energy use compared to that of a conventional building. Most important, NRG’s plan calls for adjusting building operations to minimize energy use.

Finally, the plan should establish who is responsible for managing the process (in this case, Shapiro) and how long it should continue (16 months, though Shapiro is now continuing the process beyond that period because he is interested in the information).

Industry Standard

The industry standard for M&V, both in the U.S. and internationally, is the International Performance Measurement and Verification Protocol (IPMVP); this protocol forms the basis for several other M&V standards.

Originally funded by the U.S. Department of Energy, IPMVP is now owned by the nonprofit Efficiency Valuation Organization. IPMVP consists of three volumes. Volume I defines terminology and establishes procedures for determining the savings resulting from retrofits. Volume II focuses on maintaining or improving indoor environmental quality during and following the implementation of energy-conservation measures. Volume III provides guidance on specific M&V issues, including applying M&V to renewable-energy systems and to new construction.

IPMVP’s guide to new construction, first published in 1997, “was driven by a growing market demand for post-construction validation of the performance of new buildings,” says Gordon Shymko, principal of G.F. Shymko & Associates, Inc., in Calgary, Alberta, and co-chair of the IPMVP subcommittee on new construction.

The Energy Valuation Organization, in conjunction with the Association of Energy Engineers, developed an M&V professional certification program in 2002, both to recognize qualified practitioners and to raise the professional standards within the M&V field. About 200 people, mostly in North America, have earned certification. The Association of Energy Engineers holds training seminars for those preparing to take the certification exam and anyone else interested in learning the fundamentals of M&V and working with IPMVP. More information is online at www.aeecenter.org.

M&V Systems

As with the M&V plan, the characteristics of the M&V system itself should be determined by the owner’s goals. All but the most basic M&V systems submeter individual building systems, such as lighting, heating, and cooling. Especially in mixed-use buildings, submetering different areas of the building, such as office and laboratory space, can also provide useful information.

An M&V system generally includes both sensors—which measure the volume and rate of flow, watts of energy draw, temperature, length of time, and other variables—and a central processor—which stores the collected information and helps building managers interpret it. Building automation systems typically include the central processor needed for M&V, but are “missing sensors for measuring things like watts or flow or temperature or status,” says Shapiro. “They’re also missing additional programming of the system to tally up energy usage and keep track of usage patterns.” Integrating these pieces within the existing system generally poses little difficulty, however, as long as the owner’s needs are clear.

Despite the key role of building automation systems in M&V, manufacturers of these systems aren’t actively marketing this capability. “I’m kind of surprised,” says Paul von Paumgartten, director of energy and environmental affairs at Johnson Controls, Inc., based in Milwaukee, Wisconsin. “Maybe each of us is waiting for the other,” he told EBN. Or they may be waiting for more demand from consumers. “I have never backed away from an M&V project,” says Terry Hoffman, Johnson Controls’ director of building automation systems marketing, “but the real surprise is that it is hardly ever part of a bid package.”

Whole Building Dashboards

Although many M&V systems, particularly in large commercial buildings, are custom designed for each application, plug-and-play systems with “dashboard” readouts are increasingly common, especially in small buildings. Three of these are described below.

The Agilewaves Resource Monitor provides residential and commercial building owners with real-time data on electricity, gas, and water consumption. This Web-based system can monitor data from circuits, rooms, water lines, and appliances. Agilewaves can also track, store, and analyze temperature, humidity, output from photovoltaic and solar water heating systems, utility costs, and carbon footprint information. It can also communicate with certain building management systems to actively manage loads based on real-time usage. The Resource Monitor can help reduce energy, gas, and water consumption by up to 20%, according to the company. Each system is custom-configured and can be adapted to monitor unusual flows such as runoff from green roofs. The least expensive residential Agilewaves system costs $7,900 and includes meters for whole-house electricity, gas, and water consumption, plus detailed energy or water use on seven circuits. Actual installed systems have ranged in cost from $10,000 to $80,000. If the company is able to replace the onsite central processing unit with Internet-based software, costs could eventually drop to a few thousand dollars. (www.agilewaves.com)

The Building Dashboard from Lucid Design Group got its start at Oberlin College, where students developed a monitoring system to compare energy use by different dormitories; several students commercialized the first user-friendly energy dashboard system for commercial and institutional buildings. Their company has developed touch-screen displays that show the real-time use of energy and water in an attractive and easy-to-understand manner. Most of Lucid Design’s systems have been installed at colleges and universities, including a system collecting data from 50 buildings at Elon University, but the company has several systems in commercial buildings as well. System costs are typically in the range of $25,000 to $50,000 if meters are not already in place, and $10,000 to $20,000 if meters are present. (www.luciddesigngroup.com)

The Green Touchscreen is a Web-based, interactive program designed for kiosk display to help building occupants in educational settings see and learn from energy consumption in a building. The company also offers the iBPortal, a platform for collecting, analyzing, and displaying real-time data on building performance, including electricity and natural gas consumption, water consumption, indoor air quality, and energy production from renewable energy systems. The iBPortal supports public dashboards like the Green Touchscreen, but it also can support internal building management systems. In addition, third parties can build applications compatible with the iBPortal for specific building systems. Systems average between $20,000 and $30,000. (www.qualityattributes.com)

Electricity Monitors

Tendril, Inc., foresees a thoroughly networked system of communication between utilities and electricity consumers and their individual electric loads, and has developed a number of products that move toward that end. Its Insight energy monitor is a small, freestanding display for use in the home; the Vantage is an Internet-browser-based product. Both track the cost and consumption of electricity in real time while allowing the user to see what loads are responsible for what usage. They can also issue alerts from utilities. Tendril’s systems work in concert with special wireless-enabled devices, such as electrical outlets and meters, and with TREE, the Tendril Residential Ecosystem platform. Tendril’s systems provide fine-grained understanding and control but require an array of wireless devices—and the participation of utilities—to operate at their full potential. Basic installation costs $100; more complete systems could be much more costly. (www.tendrilinc.com)

The Energy Detective (TED) is a simple, inexpensive device for displaying real-time electricity use in an entire home or on a single circuit. A transmitting device is installed in the home’s circuit breaker by clamping it onto the main incoming electrical leads. Once installed, it sends data to the receiver, a small LCD display that plugs into a wall outlet and sits on a shelf or table showing real-time electricity consumption. A more sophisticated model communicates with a personal computer, allowing peak electricity loads to be reduced (load-shedding) and providing graphs of historical electricity use. The retail price for Model 1001 with computer interface is $144.95. (www.theenergydetective.com)

The PowerCost Monitor is an affordable, real-time electricity meter similar to The Energy Detective. The transmitting device with this product clamps onto the standard electricity meter outside a home or small commercial building, and data is transmitted wirelessly to a receiver indoors. Both the transmitter and receiver are battery-powered. The display can be programmed for either single-rate electricity pricing or tiered (peak and off-peak) pricing. The user enters electricity costs (including both peak and off-peak if applicable), and the unit is then able to display real-time costs of electricity for the house. Tens of thousands of utility customers in Canada and the U.S. have received PowerCost Monitors through programs to reduce electricity demand, with measured savings as great as 18% in Newfoundland and Labrador. Retail price: $149.99. (www.bluelineinnovations.com)

The Energy Joule is a small plug-in display that shows current electricity use and cost, along with weather data. The display also changes color on a “stoplight model”—green, yellow, and red—to indicate relative energy cost. Data is sent to the device using cell-phone technology. Ambient Devices also offers the Energy Orb, a frosted glass ball which glows in stoplight colors to indicate relative energy costs at a glance. Both products are available only through participating utilities, with cost depending on the utility program. (www.ambientdevices.com)

The ECM 1220 Energy Monitor, available in both a portable professional model and a home model designed for permanent installation, is a sophisticated device for measuring electricity consumption in homes or small commercial buildings. With optional software, the unit displays kilowatt-hour (kWh) use and cost of energy used; displays average daily, weekly, and monthly electricity costs; allows users to set and track a target electricity budget; detects unusual electricity consumption that may indicate faulty equipment or other problems; and helps identify appliances and other electrical loads in need of repair or replacement. It is available in a wireless model (ECM-1220.H-X). The same monitor is available through Optimum Energy Products, Ltd. (www.optimumenergy.com), branded as the EML 2020 Portable Power Monitor. (www.brultech.com)

The Cost of M&V

The cost of M&V varies considerably depending on the complexity, accuracy, and specific features of the system. As a general guide, in Shymko’s experience, the installed equipment cost of M&V for system retrofits should be no more than 5% of the total retrofit project cost, and ongoing costs should be less than 10% of the savings associated with the retrofit. The cost for M&V with new construction, including the cost of both the installed equipment and the first year or two of operations, should be less than 1% of the total project cost for buildings larger than 150,000 ft² (14,000 m²) and less than 1.5% for smaller buildings, according to Shymko. In projects with building automation systems, the cost for M&V should be significantly lower, because these systems inherently include some M&V capabilities.

Ironically, M&V systems carry some operational costs in the form of energy use. Shapiro was surprised to learn that NRG’s direct digital control (DDC) system itself was using 600 watts of electricity continuously. The main operational cost of M&V systems, however, is in staff time to read, interpret, and act on the information they provide. “You’ve got to program the system, you’ve got to read the results, and you’ve got to see how you did and decide what you’re going to do about it,” says Shapiro. “Someone’s got to do all the head-scratching.” Doing this well generally requires training. As personnel changes, new employees must be trained if the institutional memory and the pattern of improvement are to be maintained. The dashboard systems described above make this job somewhat easier, but turning data display into energy savings still requires human attention.

Of course, M&V systems have great potential to pay for themselves over time. The payback period depends on the initial cost of the system, whether it finds inefficiencies that otherwise would have gone unnoticed, and the owner’s commitment to interpret and act on the information the system collects. Interpreting M&V data and sleuthing improvements takes as little or as much time, and money, as the owner finds useful. At NRG, Shapiro has identified some inefficiencies that would cost more to change than they would return in energy savings, but others are valuable—just a few small adjustments can pay for a system in short order.

What Are the Benefits of M&V?

The most obvious benefit of M&V is reducing utility consumption, which in turn reduces utility costs. Finding and fixing problems also extends the life of equipment, saving additional money over time. “A high-performance building is like any high-performance piece of equipment,” says Vertegy’s Thomas Taylor. “You can’t expect to turn it on and have it all run perfectly.” Bill Reed notes that in his experience it takes two years for high-performance buildings to hit their performance stride.

Verification of building performance claims carries extra value for financing and marketing. If the design team’s compensation is based on—or in any way linked to—the building’s performance, M&V can prove efficiency and manage risk. M&V also benefits client relations. “Implementing M&V lets my clients know I’m committed to following through and dedicated to getting our project to perform at, or above, the level we have claimed in our LEED documentation,” says Drew George, of Drew George & Partners, a green building consulting and commissioning firm based in San Diego, California. “Closing the loop with real data enhances our relationships. It’s all about long-term relationships.” Taylor adds that M&V brings transparency to the owner and other members of the project team: “It demonstrates that we do what we say we’re going to do.”

M&V also provides a means for quantifying and recognizing the emission reductions that result from green building. Generating the grid-supplied electricity used in buildings emits a range of pollutants. Reducing these emissions through energy efficiency or the use of nonpolluting energy sources such as solar or wind power, however, is rarely rewarded financially. This motivation for M&V is likely to become more relevant as more regions adopt cap-and-trade systems for greenhouse gas emissions, as the European Union has through its commitment to the Kyoto Protocol.

The information gleaned through M&V can also improve the design, construction, and operation of other buildings. Institutions with multiple buildings, such as universities, have an extra incentive to implement M&V plans, as the lessons learned can be applied to new and existing buildings, whether or not they have M&V systems. Ideally, M&V information also comes back to—and educates— the project team. Better information about how buildings perform compared to models can improve both design and the models. “The design community has as much to gain from this as the owner community,” says Shapiro.

Why Doesn’t Every Building Incorporate M&V?

Since M&V comes at a cost, not every building or system warrants an elaborate M&V system. One of Vertegy’s clients is the sole tenant in a small, partially occupied building. For this client, M&V would be a waste of money, says Taylor. “They can look at their bills once a month and tell where they’re at.” Reed notes that, “In my house, I’m not going to spend money for a monitoring device for my gas burner.” The smaller dashboard systems described above may be a good fit for these buildings.

Buildings that are owned and occupied by different entities are challenging from an M&V perspective. Where tenants pay for utilities, the owner has no direct financial incentive to reduce energy use, and therefore no incentive to install an M&V system. Where tenants pay a flat rental fee and the owner pays for utilities, the owner has an incentive to reduce energy use but little control over how the building is operated. USGBC addresses these concerns through two of its rating systems: LEED for Core and Shell rewards projects that install M&V systems, and LEED for Commercial Interiors rewards projects in which tenants pay the energy bills.

Even when it would obviously benefit building owners, however, M&V remains rare. The nature of the building industry, which separates design and construction from operations, is one impediment to widespread adoption. “Ours is a project-driven industry, and, for many people, it’s all about moving on to the next project,” says Drew George. “We lose all our designers after the design process,” agrees Reed, who believes it would be preferable for the project team to remain periodically engaged in the building well after it hands over the keys.

Perhaps the most common barrier to M&V is lack of interest. Energy generally represents a small portion of the cost of doing business, limiting the relative value of efficiency. “Some people don’t want to dedicate the time and resources to operate the building as long as it’s running,” says Taylor. Sometimes even if the project team sets up the building to facilitate M&V, the owner fails to take advantage of the system because nobody on staff understands it or takes the time to interpret the results. “Most people don’t have a very clear goal of where they want to get to with energy efficiency,” says Shapiro. “People want to look forward,” he continues. “They don’t want to look back, and they don’t want to look at problems.” Evidence of poor performance can also be an embarrassment, or even a liability, to the owner or the design team—especially for buildings designed to be energy efficient.

Final Thoughts

Concerns about climate change, the regulation of greenhouse gas emissions, the growing popularity of LEED, and rising energy costs should all boost interest in reducing energy use, and, in turn, spark new interest in M&V. Even though M&V represents an investment in both money and time, and often carries a risk, it also brings with it considerable benefits.

Taylor encourages project teams to install M&V systems and, once they’re installed, to use them. “You might pour your heart and soul into the design but find out you’re only at half the performance you thought you were at. Don’t be embarrassed; be proud that you have the data, and go out and fix it,” he says. “Take a bold step.”