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.

How much air is your house leaking? Are you unknowingly slurping in dirty air from your garage and attic? Perhaps a blower door test can help you find out.

"I went to the ServiceMagic Web site that I learned about editing a Home Energy article," says Tom. "Within less than a minute after I entered some basic information about my house and what I was looking for in the way of an energy audit, the phone rang." It was Sustainable Spaces, a home performance contractor located in San Francisco. Tom made an appointment for his audit for the next week. "They were offering a 'Stimulus Special' for $395."

The house Tom shares with his partner Dmitri was built in 1907. "The home has never been remodeled," says Tom. "We recently had the furnace replaced with a hot water radiant system. We have been careful to keep to the original features of the home, so we got our radiators from buildings built around the same time that used to be part of the heating systems in buildings at Fort Baker." They also installed a renewable energy source. "We installed photovoltaic (PV) panels on our roof, but we should have had the audit first to show us how to use less energy and save on the PV.  Our annual true-up statement says we owe $75 for electricity, but I want to get that down to $0!"

Rob Mitchell, an experienced contractor who knows a lot about Bay Area houses, came with two younger men for an audit of Tom and Dmitri's 102-year-old home. The crew closed all the exterior doors and windows, installed a "blower door" in the main doorframe, and depressurized the house. Immediately, dust and insulation particles began to pour through the "pocket doors" from the attic. After taking some measurements to get a general sense of how leaky the house is, and blocking some of the major air leaks, the crew from Sustainable Spaces then pressurized the house. "We walked around the house with a liquid pencil, which showed there is airflow around switch plates, gaps in the baseboard where the home is connected to the outside, and the cabinet in our kitchen where there used to be 'torpedo tubes,' which used to hold hot water heated by the wood stove, and other places" says Tom.

So the old house has some problems with air leakage, which means heating energy being lost to the outside. The crew also found out that the humidity in the kitchen was 20% higher than that on the outside of the house. "We both took showers that morning, and I had a cup of hot tea," says Tom. That was enough to keep the humidity high a few hours later.

Since the home has no mechanical ventilation, moisture build up could lead to mold growth on surfaces in the living spaces, or-even worse because it is hidden-within the walls. Mold can degrade building materials and create poor indoor air quality. Tom has allergies and a moldy house could make it difficult for him to breathe. Since Tom is living in the mild climate of the Bay Area, where we can open windows and get fresh air other ways in our leaky houses, the moisture may not hang around long enough to be a problem. If he lived in a cold climate such as Minnesota's, or a hot-humid climate such as Atlanta's, fixing the air leaks in his house without adding mechanical ventilation could create a "sick house", meaning one with poor indoor air quality due to mold.

"We won't get the report until next week," says Tom. The report will include specific numbers for air leakage from the house to the outside-or in this case between the living spaces and the attic and basement. Too much air flow means lost energy and too little means a sick house. The report will also give a range of measures that will make Tom and Dmitri's house healthier and more energy efficient. "We'll decide what measures we want done when we get the report. We made our heating system more efficient with the radiant system that heats the living spaces and provides us with hot water. We use half the gas now to heat water than we did before. So spending a lot more on fixing the building envelope doesn't make so much sense to us right now. We'll probably fix the big leaks by air sealing around the attic. And we may insulate under the floor between the living spaces and the basement."

"I wanted to have our house audited mostly because I'm curious," says Tom. "And we want to save energy." But from now on when Tom talks about home performance, and the importance of healthy and efficient homes, it will take on a whole new dimension-the homeowner's perspective.

37.8686 -122.267

This attic hatch insulation kit install is making the author use some choice language.

I promised Michele that I will practice the Yoga of home improvement projects and keep the cursing down to a minimum. My home improvement projects usually involve some cursing. I worked part time as a janitor when I was in high school and that's when I learned some pretty spicy language. I didn't intend to write about cursing here, but since I am in this so deep now, then damn it, I may as well connect the topic to some cutting edge scientific research. You got a problem with that?

British scientists found that cursing takes away pain. When people put their hands in a tub of cold water and cursed, they could hold their hands in longer than if they said things like, "butterscotch." If you don't want to take my word for it, you no-good so-and-sos, the research results were published in the online journal NeuroReport.

The attic hatch insulation kit will save us some energy losses and utility bill pain in the long run. According to the DOE Weatherization Assistance program, a gosh darn uninsulated 10 square foot attic hatch in a 100 square foot insulated attic can decrease the overall R-value of the attic floor by more than 50%! For example, an attic with R-38 insulation everywhere but on top of a stinking quarter-inch plywood hatch-with an R-value of approximately 0.3-will have an overall R-value of only R-17. What a freaking waste! Bloody hell!
You can find out more about insulating attic hatches at the Department of Energy's Energy Efficiency and Renewable Energy Web site. Do it now!

37.8686 -122.267

Non-profits like Green For All are working with federal and state goverments to usher in new "weatherization worker" legislation.

Tuesday, July 21

There are 3,200 people here for the conference in Indianapolis! This is more than twice as many as the last time. Heard from Gil Sperling, Program Manager for the Department of Energy’s Weatherization Assistance Program, and others at opening plenary. Some buzz about Davis-Bacon prevailing wage legislation. Department of Labor created a new category "weatherization worker" and is polling organizations around the country to come up with prevailing wage numbers. Department of Labor staff is here to get feedback.

Five U.S. Territories are now part of the Weatherization network.

Van Jones speaking at lunch today.

Will set up display for later today. Something like 94 exhibitors are here, including heavy hitters like Home Depot and Sears. Will try to convince Home Depot folks to carry Home Energy Magazine in stores.

(later)

Van Jones, White House green jobs czar, spoke to weatherization workers at the National Weatherization Training Conference, "You are the quiet heroes. Your job is to take the inhalers out of little girls' pockets; little boys pockets."

No, he is not encouraging shoplifting, but the kind of homes that do not aggravate kid's asthma. A green home is an energy efficient and healthy one. That's something the weatherization community has known since the DOE Weatherization Assistance Program began in 1976.

Wednesday, July 22

At the awards lunch today, Gil Sperling mentioned that the Dept. of Labor (DOL) is making good progress in discussions with local weatherization agencies to determine the prevailing wage for a new classification of worker, the weatherization worker. The Davis-Bacon legislation from a decade ago (?) requires that organizations receiving federal government project money must hire people at the prevailing wage for similar work in the area. The legislation is being applied to the funds coming through the American Recovery and Reinvestment Act (ARRA) of 2009, (also known as the Stimulus Bill) for weatherization efforts. DOL came up with a new classification of worker, weatherization worker, in order to help the states comply with the Davis-Bacon requirements.

If the prevailing wages of construction workers were the standard, in New York, beginning weatherization workers would have to make $50 per hour! Weatherization agencies all over the country want to pay their workers well, but those kind of wages for beginning workers would wreck the budgets of most of them. So the new classification and prevailing wages will help agencies to pay a living wage, increase pay as workers become more experienced, and allow the agencies to live within their budgets. DOL staff are here in Indianapolis, and there listening sessions have been packed!

Thursday, July 23

A friend asked me What is the headline for the conference? I think it should be Weatherization Gets Down to Business. I am reminded of the ramp-up to the war in Iraq, and the war profiteering that is probably still going on. I remembered the “lost” $8-billion in the first months of the war. And I wonder if that kind of corruption will enter in the “war for energy security and green jobs and against global warming.” It probably will, because humans are involved. But the level of accountability here is very very high, and the expectations are very very clear. And I get the sense that, this time, the adults are in charge.

37.762611 -122.409719

Stanley Jevons first described the take back effect in 1865, so this is nothing new. Jevons observed that new efficient steam engines decreased coal consumption, which led to a drop in coal prices. But the lower prices meant that more people could afford to use coal, and so coal consumption increased.

The "Snackwell Effect" takes it's meaning from the habit of people on diets who eat lots of low-cal snacks that add up to many times the calories of a regular snack. The example given in both articles mentioned above is a West Virginia couple that bought an energy efficient washing machine to replace their old inefficient one. Their energy bills were no different after the conversion. Turns out they were doing more loads of laundry, even washing one piece of clothing in one load, because they were lulled into complacency by their energy efficient purchase.

I asked Jim McMahon, the head of the Energy Analysis Program at Lawrence Berkeley National Laboratory (LBNL), about the Snackwell Effect and appliance energy use. I recently heard him speak about the great efficiency gains made between the first energy crisis brought on by the Arab oil embargo in 1973, and today. Those gains are significant; refrigerators today use about half the energy on average than they did in the 1970s. "This effect [Snackwell Effect] has been studied for a long time, [it was] formerly called the rebound or take back effect," he says. One 2001 study concluded that for every gain in energy efficiency, about 10% is taken back by an increase in energy use. Greater air conditioner efficiency, for example, may mean that people lower their thermostats, since they expect their energy bills to be lower, and this eats into the efficiency savings. "I think that there are a number of energy-using devices where consumers do not exhibit the Snackwell effect, such as refrigerators or televisions. In those cases, in my view, the usage behaviors are unrelated to the cost of energy, at least for most households in the United States," says McMahon. He does admit that more study is needed in this area. A 10% take back effect is significant, but certainly not a barrier to serious energy efficiency improvements.

Karen Ehrhardt-Martinez, a sociologist, studies human behavior and energy use for the American Council for an Energy Efficient Economy (ACEEE). "The relationship between energy efficiency and energy consumption is not as straightforward as it may initially appear and as some people like to portray it."

The trends show that: 1) residential energy consumption increased by roughly 57% between 1970 and 2005; and 2) residential energy consumption per capita increased by only 7%".

According to Ehrhardt-Martinez, a bigger problem than the 10% of energy lost due to the take-back effect-or the Snackwell Effect-is the proliferation of energy using, albeit more efficient, devices in American homes; lifestyle choices, such as the dramatic increase in the size of homes while families got smaller; population increase; and the "invisible" energy, such as standby power or phantom loads, that is hidden from consumers. "However," says Erhardt-Martinez "if we were able to combine efficiency improvements with better lifestyle choices (i.e. smaller, more energy efficient houses), smart purchasing behaviors, and improved information mechanisms that allowed consumer to actively manage their energy consumption, then we could have a much more dramatic impact on both household level consumption as well as state and national level consumption."

37.8686 -122.267