Skip to Main Content U.S. Department of Energy
Breakthroughs Magazine

Solutions Update

Efficient "can" lights to plug homeowners into energy savings opportunities

It turns out that the most popular form of residential lighting is generally the most inefficient. So inefficient, in fact, that beginning October 2005, new building codes in California will effectively limit new installation of incandescent recessed fixtures, commonly referred to as "can" lights or "downlights."

The Department of Energy, through Pacific Northwest National Laboratory, is working to improve the efficiency of can lighting. PNNL estimates that at least 400 million downlights currently are installed in U.S. homes.

"The widespread use of inefficient recessed cans means there is a huge opportunity to reduce energy use and operating costs by using efficient compact fluorescent lamps (CFL) and redesigning fixtures," said Jeff McCullough, senior research engineer at PNNL.

These fixtures are energy hogs because most use inefficient incandescent bulbs. But that's only part of the problem. They also indirectly lead to energy use by heating the room, which adds to air conditioning loads. And, since many are not airtight, recessed downlight fixtures can also allow heated or cooled air to escape into attic spaces.

"Use of CFLs alone could cut the number of watts each fixture uses by two-thirds."
- Jeff McCullough
PNNL Senior Research Engineer

"Use of CFLs alone could cut the number of watts each fixture uses by two-thirds," McCullough said. "In addition to efficient lamps, we're going to need airtight fixtures that stop the air from escaping to the attic." Both sound like simple fixes, but combining the two creates a technical challenge. Airtight fixtures installed in an insulated ceiling cause heat build-up, which can impair lamp performance and lifespan.

Researchers at PNNL are working with manufacturers to improve performance of reflector-type CFL replacement lamps and to redesign fixtures that are hard-wired for CFLs.

Acting as a matchmaker between manufacturers whose products must meet certain requirements and potential large-volume buyers, the Lab has made progress. To date, three CFL reflector lamps have passed PNNL's stringent 6,000-hour elevated temperature life testing procedure. More information on the specific models, produced by Phillips and Feit, can be found at The results of PNNL's efforts are expected to speed new high-quality products to market and allow them to be introduced at more competitive prices. But R&D must continue.

"We are just entering the second phase of lamp testing in order to find more reflector lamps that can stand up to the high heat environment of airtight can fixtures," said Linda Sandahl, program manager for the reflector-CFL effort.

For the can fixtures themselves, PNNL's rigorous tests have resulted in recommended design changes. The changes address the effects of heat buildup in insulated ceiling fixtures, which can cause the ballast—the component responsible for starting the lamp and maintaining the current—to fail prematurely. PNNL relocated the ballast, taking advantage of cooler adjacent ceiling spaces, thus extending its lifespan.

PNNL's program, which involved long-term testing simulating 7 to 8 years of operation, identified five fixtures that met stringent performance requirements. Building on successes with previous market transformation efforts, the Lab is continuing to work with manufacturers and potential buyers to introduce more high-performing, airtight downlight fixtures that are hard-wired to use energy-efficient CFLs.

Environmental biomarkers provide early warning of disease

Biomarkers provide scientists with crystal ball capabilities for predicting biological responses to environmental changes.

Outbreaks of Avian flu or "bird flu" during the past several years have disrupted the poultry industry. More ominous is that the virus spreads to humans. The ability to identify this disease early on may help prevent epidemics that wreak havoc on a country's economy and take lives.

Now, researchers at Pacific Northwest National Laboratory, through the multi-year Environmental Biomarkers Initiative (EBI), are developing new techniques and tools for identifying these early warning signals also known as environmental biomarkers.

Environmental biomarkers are biomolecular signatures—a set of proteins, genes, metabolites, or lipids—that when expressed together present a unique pattern of molecular change in an organism and identify a response to a specific environmental stressor. These signatures may indicate a specific biological response to pollution, subtle changes in the environment, or deliberate releases of toxic substances.

Disease in organisms and damage to the environment are progressive events that may take days, months, or even years before showing outward symptoms. The goal is to identify early indicators, before the damage is done. "Uncovering these environmental biomarkers may allow health care professionals and environmental managers to reverse the chain of events that could otherwise lead to permanent damage," said Ellyn Murphy, EBI Lead.

"How many times have we heard, 'if we had caught the disease earlier, it could have been cured?'" Murphy said. "Discovering molecular signals early may allow us to manage the long-term damage to individuals and ecosystems associated with pollution from everyday sources such as traffic and industry."

A particular concern is the health effects of engineered nanomaterials that are increasingly being used by industry. Nanomaterials often display different properties from their macroscale counterparts, which put regulators in a bind in assessing the toxicity of these materials. "Rapid screening methods for assessing the biological activity of nanomaterials is one aspect of biomarker discovery that will have direct impact on emerging health concerns," Murphy said.

According to Murphy, the health impacts of engineered nanomaterials-microscopic materials containing particles down to one millionth of a millimeter in size-is a future direction of the Environmental Protection Agency's particulate matter research program. This direction fits nicely with PNNL's expertise in nanomaterials and research on modeling and understanding the respiratory tract.

A second focus area that also relies on an understanding of the respiratory system is the discovery of biomarkers associated with zoonotic agents. Zoonotic agents, such as anthrax, can jump between animals and humans and are a major concern in biodefense. As with nanomaterials, the entry point is the respiratory system and early biomarkers for exposure and response are needed to manage and prevent widespread outbreaks.

The final focus area within EBI involves applying biomarker discovery to ecosystem damage. "This is perhaps the most challenging area within EBI because it involves the development of several tools to probe genes, proteins, and metabolites to understand both the structure and function of a complex subsurface community in the absence of the genome for specific members of that community," Murphy said. "Clearly this is high-risk but extremely high-impact to the future of environmental management."

EBI is building on PNNL's extensive investments in systems biology, proteomics, visual analytics and data fusion, and cellular imaging, as well as the Laboratory's core capabilities in environmental science, toxicology, and material science, to name a few.

"Prediction is the scientific challenge of the 21st century," Murphy continued. "And Environmental Biomarkers could fundamentally change the way we approach environmental health, assessment, and management. It is a tremendous challenge but very exciting."

Breakthroughs Magazine

In this issue...