The window testing facility at Lawrence Berkeley National Lab. (Photo: LBNL)

Windows may not be as sexy as solar panels or electric cars, but they play a major role in energy efficiency. Buildings are responsible for 40% of the country’s energy use, which is why researchers at Lawrence Berkeley National Laboratory are trying to improve windows by making them smarter.

As Berkeley Lab engineer Howdy Goudey demonstrates in his lab, studying windows involves some pretty complex physics.

“So we use an infrared camera to study heat transfer in windows,” he says, pointing to a normal-looking video camera that senses heat instead of visible light. Goudey uses the camera to study how windows lose energy.

For the most part, windows simply aren’t good insulators. They leak heat in the winter when we want a warm house and they let heat in during the summer. Many homes still have single-pane windows, which were the name of the game in the 1940s and 50s when California was booming.

That changed when energy prices sky-rocketed in the 1970s. Double-pane windows became common. And then came double-pane windows with invisible coatings, which are twice as efficient. Today, they make up more than half of windows sold.

Measuring Low-e Windows

Goudey demonstrates how they work by turning on two heat lamps. “You’ve seen them in a diner keeping food warm," he says, putting them behind two identical-looking double-pane windows.

We stand in front of one window, which feels like standing in the sun. “But if you hold your hand to other one, compared to this one, it’s very dramatic,” Goudey says.

An infrared image of two windows during winter conditions, as seen from the inside of a room. The window on the right has a low-e coating while the window on the left doesn't. Warmer temperatures mean a better insulating window. (Image: LBNL)

The second window is cooler because it has a low-emissivity coating, or low-e, as its known. It’s an invisible layer of metal on the glass that acts as an insulator. And it does one more thing.

When sunlight shines directly through a window, it provides both light and heat. Most of us want light coming in, but heat is the last thing we want on a hot summer day. So, the coating on the window blocks the heat from the sun (in the form of infrared light), while letting in the visible light. This is known as solar gain. (Check out this guide for more on what to look for when buying windows.)

“If you have a few windows in a room with direct sun on them, its equivalent to running a little space heater. So it’s significant energy,” says Goudey.

However, on a cold winter day, the extra heat from sun would be helpful. “You’d actually like that solar energy to come in and help heat the space,” he says.

That’s why researchers are working to develop a “smart” or dynamic window that can change based on the weather or temperature.

Using Nanotechnology to Make Windows Smarter

At Berkeley Lab’s Molecular Foundry, Delia Milliron grows tiny nanocrystals that will eventually become a window coating.

“Nanocrystals are very small,” says Milliron. “Way smaller than you can see with your eyes. And so that’s why when we spread them out in a coating on the window, you don’t see anything.”

Milliron’s coating is dynamic. In one setting, it lets in both the light and heat from the sun. But, apply an electric charge of a couple volts and the window blocks the heat from the sun, while still letting light in.

Ideally, these windows would be controlled by your heating and cooling system, which could adjust them based on the weather. Milliron and her team are currently working on the coating itself. Their next step is to build a full-scale prototype. Other companies also have similar kinds of dynamic windows in the works.

Windows as Energy Suppliers

This changes the conversation about windows, says Stephen Selkowitz, head of building technologies at Berkeley Lab. Before, windows were energy losers. Now, windows could actually make buildings more efficient. And that means big cost savings.

“If we add up all the energy and economic impact of windows in the US, it costs building owners about $40 billion a year. And I’d rather have the $40 billion in my pocket than sort of sending it out the window,” says Selkowitz.

Smart windows could start appearing in larger projects like office buildings next year and should be more widely available to homeowners in three to five years. But they could be twice as expensive as today's windows. Selkowitz expects the cost coming down as manufacturing ramps up.

“The biggest expense in replacing windows is often the labor of replacing the window. And if you already decided to put a new window in, the marginal cost of going to a much better window is almost always worth it,” he says.

So, while it may be only a few tech-geeks that spring for smart windows at first, Selkowitz says that leads the way for the rest of us – and for new buildings codes, where technology can have a much broader impact.

The new PC—Policy Collaboration

It started in Santa Clara County, then spread to Marin, and now its everywhere in California; builders, developers, city governments, and environmentalists, all getting along and creating green building standards together. It’s the new PC—Policy Collaboration.

The Silicon Valley Leadership Group (SVLG), a business development group, got things started in Santa Clara County by meeting with city mayors to discuss a coordinated building policy to replace the patchwork that existed in 2007. Once they got the mayors go ahead, SVLG got the endorsement of the Santa Clara Cities Association. Then representatives from the cities formed a group called the Green Building Collaborative (GBC), and the group began to meet with builders and to enlist the help of builders associations like the Building Owners and Managers Association (BOMA). With all those acronyms coming at them, the city councils in Santa Clara County, one by one, succumbed to the contagious enthusiasm and passed the green building ordinances.

Marin County decided to go ahead and do its own collaborating. San Rafael Mayor Al Boro and Planning Director Bob Brown started talking with other city officials in Marin about a coordinated green building policy. They formed a task force with representatives of all the cities, recruited some building experts, and created a really cool sounding acronym, BERST, for the Building, Energy, Retrofit, and Solar Transformation task force. The group reached out to builders, designers, and business groups to try to form a consensus. It was tough work, which for Brown became a half-time job. Cats and dogs is easy—this was bob cats and wolves. But goodwill reigned and eventually everyone agreed on a green building policy that looked a lot like the one in Santa Clara (see Table).

One of the features of the code is that homes larger than 7,000 square feet of floor area have to compensate for size by being net-zero energy users. In other words, they have to produce as much energy—through solar electric PV and other renewable energies and by being extremely energy efficient—as they use over the course of a year.

San Rafael was the first city to adopt the green building ordinances. Three other cities have signed on, and more will be voting in the fall.

Leif Magnuson, Pollution Prevention Coordinator at the San Francisco office of EPA, was the prime mover in spreading the collaborative spirit to Sacramento. Magnuson gathered California stakeholders at an ACI conference. ACI is a national training organization that for 25 years has hosted regional and national training and networking conferences bringing together everyone interested in sustainable home building and renovation, from weatherization professionals, energy auditors, and small home performance contractors to policymakers, production builders, manufacturers of building materials, and representatives of big box home improvement stores. And after a while, they had to create an acronym to match their ambitions—HERCC, for the Home Energy Retrofit Coordinating Committee.

It was only a matter of time before the California Energy Commission (CEC) got involved—in fact representatives of the commission were a part of HERCC from the beginning. So it is no wonder that the HERCC recommendations greatly influenced the CEC green building regulations that became a part of the California Title 24 building codes. The investor owned utilities all throughout California support the green building policies championed by HERCC through its rebates offered to builders and homeowners.

From the beginning, HERCC wanted to put in place an infrastructure to support green building and retrofits beyond the years of the American Recovery and Reinvestment Act (ARRA), which flooded federal dollars to the states that will be running out in about a year. HERCC will outlast ARRA, thanks in part to BERST, which owes its inspiration to groups like SVLG, GBC, and BOMA. Go CA!

(Many thanks to Elise Hunter, who recently served as the government relations manager at Build It Green and who is now studying for advanced degrees in sustainable enterprises at the University of Michigan, for putting together the facts in an upcoming article about policy collaboratives for Home Energy Magazine.)

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A technician checks the combustion efficiency and safety of a water heater—an important part of any home energy audit.

I hope I’m certifiable. I’ll find out in about a year when I’ve completed all the training and taken the written and field exams to become a Building Performance Institute (BPI) certified Building Analyst. The certification would allow me to perform energy audits on homes and maybe even get paid for it if I started an auditing business or joined an existing company. The certification would not prepare me to perform energy upgrade measures, such as air sealing and insulating an attic, only recommend the most cost effective ones. Many energy auditors work with a team of trusted contractors who can do the work the homeowner chooses.

My publisher Tom White and I decided that going through the kind of training that we have been pushing in our magazine will give me a more realistic view of the home performance industry, and the people who are just entering it now—the new weatherization workers, and newly minted technicians, contractors, and small business owners who will help build the new green economy. And it’s an excuse to get off my butt and out of the office more often. If I get certified, I’ll need to continue taking classes and have hands-on experience in the field to stay certified.

There are three kinds of certifications for a wannabe energy auditor to consider: certification as a Building Analyst through BPI; certification as a HERS (Home Energy Rating System) rater through the Residential Energy Services Network; or one of many “green builder” certifications that exist nationwide. I think the Building Analyst is the most basic. The training follows closely that of a HERS rater, but HERS raters need to become expert at rating software; it’s a bit more involved. I thought about being certified through Build It Green California as a Green Building Professional. But once I’m certified through BPI, I think it would be a small step to being certified by the other organizations.

Now I am asking what many people in the midst of career decisions are asking. Where do I go for the training and how much will it cost? BPI is in Malta, New York. (Might as well be Malta, the country.) Fortunately, BPI has hundreds of affiliates and approved trainers all over the country. There is also online training, and trainers who will travel to your hometown, as long as you have several people interested in the training. My plan so far is to complete an online training course through well-respected training organization, Saturn Online. That will prepare me for the Building Analyst written exam. I can even take the exam online. The course costs $595, plus about $70 for a book and field manual. Once you start the online course, you have about 8 weeks to complete it, so I can study and take the quizzes and final exam in my spare time—maybe over the holidays. The written exam fee is $225.

But you can’t get all the training you need online, nor would I want to. (Remember me wanting to get off my butt more often?) Saturn also offers three day intensive hands-on field seminars in locations in several locations around the country that culminate in the Building Analyst field exam. I have friends in Portland I haven’t seen in a while; maybe I’ll go there for my field training. The field seminar costs $950. If you want to take the exam at the end of the seminar, there is an additional $350 charge for proctoring. Total costs of going for BPI Building Analyst certification: $2,190. The value of certification: priceless.

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By reporter Marjorie Sun.

I got interested in this story after hearing Silicon Valley venture capitalist Vinod Khosla speak at a conference this fall in Sausalito. He explained how he decides where to invest in green tech and it was fascinating. He and other top venture capitalists think they can help stop global warming and make a ton of money at the same time. You can listen to Khosla's talk on a webcast and listen to all sorts of entrepreneurs and v.c.'s talk about the latest renewable energy projects.

Khosla says to achieve a huge reduction in greenhouse gas emissions fast, we have to think about solutions that make big cuts in emissions and will be widely adopted. Buying a Prius is fine, he says, but it's really just "fashion." We need solutions that people in India and China will buy, Khosla says. To him, the key issues that guide his investments are cost, scale, and adoption. If a renewable solution isn't cheaper than coal, forget it, he says. Geothermal "is nice, but it doesn't scale."

Same with wind. It's "a great technology, but it's a toy." As for hydrogen fuel, the adoption risk is too high. Again, forget it, he says. The focus should be a war on coal, oil, and the manufacturing of cement and steel, which are huge emitters of carbon dioxide. (He's a major investor in Calera, an alternative cement maker in Silicon Valley.)

One more area for potentially huge gains is to improve energy efficiency, such as lighting. Another legendary venture capital company, Kleiner Perkins, is also racing to develop renewable energy solutions and make a fortune. (Khosla is a former partner there.) Kleiner's efforts were profiled in a cover story in The New York Times Sunday Magazine recently

With the Obama administration, it will be interesting to see what new federal policies– tax, economic and regulatory– will be adopted to accelerate solutions and spur more investment during a double whammy of crises: the economic meltdown and climate change.

Listen to the Building Blocks Go Green radio report online.

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