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The gap between predicted and measured building systems’ performance presents a major challenge. The first step towards closing the gap is to expose performance. Photo by Elizabeth Schwegler

The gap between predicted and measured building systems’ performance presents a major challenge. The first step towards closing the gap is to expose performance. Photo by Elizabeth Schwegler

Is Guaranteed Building Performance Possible?

The construction industry is in a position to help lead the effort to guarantee that buildings deliver on performance promises, according to a leading authority on energy-efficient buildings and ENR’s 2014 Award of Excellence winner.

Guaranteed building performance has the potential to create more efficient buildings for the benefit of the owner’s bottom line, building occupants and the environment. That’s the assessment of Steve Selkowitz, who has led Lawrence Berkeley National Laboratory’s Building Technology and Urban Systems Department for 20-plus years and has been recognized for his commitment to advancing building performance including the 2014 Award of Excellence from Engineering News-Record.

Selkowitz pointed out that the amount of energy used by commercial buildings each year in the U.S. amounts to about 50 percent of the annual cost of construction. “If that energy cost could be cut in half, the balance could be shifted into construction or renovation costs rather than go up the chimney,” he said.

Tighter building codes and environmental regulations, rising utility costs, the need to create comfortable and productive workplaces, and commitment to sustainability are helping to drive deeper discussions around guaranteed building performance. Many claims for improved energy performance are made, but the outcomes are not always as anticipated. 

“DPR clients are beginning to pay more attention to long-term building performance—taking a life-cycle view of buildings versus a first-cost view,” said DPR’s Andrew Arnold who helps DPR customers develop virtual facilities management solutions. “While it isn’t happening as much in North America as in other parts of the world, it is generating more dialogue among owners about the total cost of ownership of their buildings.”

“Most people initially like the concept of guaranteed building performance,” added Selkowitz, “but they say, ‘Wait, how can I guarantee what an owner or occupant will do downstream?’ The key is to first define the energy use target, execute a design, then construct and operate plan that keeps those targets in mind as a myriad of later decisions are made.”

The way a building is used, operated and maintained is beyond the direct control of the construction team, but it can be influenced by decisions made during design and construction. For example, sensible design of occupant-friendly lighting controls, with intuitive user interfaces, clear installation and commissioning plans for contractors, and training for office occupants can help ensure that the controls deliver the expected energy savings and comfort. That, along with selecting attainable targets with proper design team incentives, determining the duration of the guarantee, and defining the method of measuring performance, are among the biggest stumbling blocks to guaranteeing building performance. Selkowitz offers up suggestions for minimizing those challenges and offers a glimpse of the future for energy-efficient commercial buildings.

ACTUAL PERFORMANCE

The gap between predicted and measured building systems’ performance presents a major challenge. The first step towards closing the gap is to expose performance. Determine what works, quantify how well it works, and for how long.

When a building fails to meet performance goals, a deeper look is needed. Hard data on how products and integrated systems perform needs to be collected, analyzed and shared, which will help boost predictability, advance energy modeling and use of other simulation tools, and ultimately improve products and systems.

Toward that end, DPR has joined a new consortium assembled by Selkowitz to contribute real-world data about equipment, systems and building performance from projects.

Selkowitz is also the scientific leader behind the development of Berkeley Lab’s new FLEXLAB (Facility for Low-Energy Experiments in Buildings). The world’s first “rent-a-lab” for controlled building performance testing, FLEXLAB consists of four plug-and-play outdoor structures that can be used as live, full-size mock-ups for demonstrations, testing or developing energy-efficient building technologies, products and systems.

TRANSPARENCY

Better transparency about energy consumption in real time (day-to-day and month-to-month) and data on where that consumption is occurring would also make guarantees on building performance easier.

“Someone once described the challenge faced by building-energy managers as similar to a food shopper in a supermarket, where the products have no cost labels and shoppers check out with no clue as to what items cost,” said Selkowitz. To make matters worse, the shopper “gets a bill a month later. This is essentially how we manage energy costs in buildings today.”

Disclosure laws in several cities now require owners to publicly disclose the annual energy use of buildings. Real-time measurement of energy consumption and tracking whether current consumption is meeting the established goals would enable owners or users to assess what changes should be made day-to-day, or even hour-to-hour, to compensate. Ideally, buildings might be outfitted with a desktop dashboard that shows local energy usage to each occupant, and a central dashboard for the facility operator to track and manage overall consumption.

PERFORMANCE METRICS

Owners and occupants will have their own objectives for a building, whether it will be reducing annual energy costs or creating a more productive environment for employees.

Guarantees on building performance should include metrics that embody objectives, are measurable, and clearly spell out boundaries, limitations and possible adjustments, such as occupancy, climate, maintenance programs and equipment failure.

“Jumping immediately to performance guarantees may be challenging in the short term. However, shifting to outcome-based regulations and guidelines from the primarily design-based building codes and certification programs would encourage and assist with the adoption of guaranteed building performance,” said Selkowitz. He pointed out that a small number of owners are already demanding these guarantees in their contracts for new buildings.

AUTOMATED & INTEGRATED SYSTEMS

The impact of occupant behavior is also the subject of much debate and study. Can occupants be trained and/or motivated to control and operate HVAC, lighting and shading to optimize energy use, or does occupant behavior contribute to the wide variance in building performance seen today? The jury is still out. However, automated and integrated systems, such as an active building envelope with sensor-controlled shading and lighting systems, would provide a measure of predictability in operations and maintenance, an important element in guaranteeing building performance. Compatible specifications and open standards are required to maximize the impact of such systems. To be successful, Selkowitz noted, the automated systems must work well and be occupant-friendly.

A few companies and partnerships have produced vertically integrated lighting and shading systems. The team on large capital projects can influence manufacturers. “As researchers we have only modest direct impact on what manufacturers offer. But working closely with owners and contractors, we are in a better position to help create new interoperable products and systems,” said Selkowitz.

“Looking ahead, buildings will become more intelligent, grid-friendly and responsive to occupant needs. Most energy consuming devices will talk to a building-wide network, which will be monitored with fault detection and diagnostics, will continuously adjust their operation and report to a dashboard displaying real-time usage,” says Selkowitz. “The vision and pathway to do a better job is there, but we’re not there yet.”


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