Blower door equipment is used to measure a home’s
air leaks. A blower door test is part of the evaluation for
determining a home’s HERS Index.
Photo by: D&R International

Remember the day when most men knew the horsepower of their muscle cars? Now most of us are concerned about miles per gallon. But what can we use to bring prestige to our houses? It used to be that a large square footage gave us bragging rights. But if all goes according to the plan of the Residential Energy Services Network (RESNET), the talk around the water cooler will be “What’s your house’s HERS score?”

Home energy ratings have been around since 1981. The idea began in the mortgage industry to credit the energy efficiency of homes towards the home mortgage. An energy efficient home means that the homeowner is spending less each month on electricity and natural gas and therefore has more to spend on the mortgage. RESNET has been developing the Home Energy Rating System (HERS) since 1981. In the beginning, it was the higher the HERS score the better. But because of the more widespread introduction of renewable energy systems, such as photovoltaics (PV) and solar hot water systems, into homes, and the ability of many houses today to produce as much electricity and/or hot water as they need over the course of a year-these are called net zero-energy houses-a HERS Index of “0″ is the goal. A HERS score of 85 means that a new home meets Energy Star standards. A HERS score of 150 means you’re living with an Energy Hog. The typical existing home in the United States has a HERS Index of 130.

HERS raters look at a home’s heating and cooling efficiency, insulation levels, appliance and lighting energy use, window efficiency, a home’s solar orientation, and other factors that are tailored to the home’s climate region, and use computer software to calculate a HERS index.

Some readers my be asking, “Why should I care?” You should care because the HERS score is becoming the standard du jour for homebuilders. If you want a bigger, energy efficiency mortgage, you’ll need a HERS rater to measure the efficiency of the home you want to buy and to tell you what retrofits you need to do to qualify. If you are a builder and want to catch the “green wave” by earning an Energy Star rating for the new homes you are selling, you’ve got to get those homes rated by a certified HERS rater.

Many states have Energy Efficiency Portfolio Standards and Energy Efficiency Credit trading, and many more will in the future as we move towards national standards for meeting greenhouse gas emissions goals. The HERS Index is in place to serve the need for a third-party verifier of energy efficiency improvements.

Want energy efficiency tax credits for your new home? Better find a RESNET-certified rater. Moving to Canada? The Canadian RESNET, or CRESNET, is in the process of accepting the U.S. standards. I don’t know the HERS Index of my home, but we did recently have some air sealing and insulation work done-but not quite to Energy Star standards. My guess is we’d score about 100. What’s your HERS score?

A sample of switchgrass at Sandia National
LaboratoriesIt doesn’t need to be said that there’s a heated debate about how to mitigate greenhouse gas emissions with actions that lessen our society’s carbon footprint. Biofuels like ethanol or biodiesel are one option. They’re touted as being carbon neutral because the CO2 they emit comes from crops which had previously sequestered them in the atmosphere. In contrast, petroleum produces CO2 emissions that had previously been buried deep in the earth’s crust, adding to the other green house gases in the environment. For example, the U.S. Department of Energy - citing research by the Argonne National Laboratory – states that ethanol derived from corn emits 25% less greenhouse gas emissions than petroleum and that the savings with cellulosic ethanol, made from a feedstock like switchgrass, are much higher, in effect producing no additional greenhouse gases.

So when QUEST decided to move forward on producing a story about biofuels, I welcomed the opportunity to assist Series Producer Josh Rosen in its crafting. Being QUEST, we weren’t content to merely renumerate the different kinds of biofuels and how cellulosic ethanol is more efficient than corn-based ethanol. Instead, our story focuses on the pioneering work being done by researchers affiliated with the Joint BioEnergy Initiative (JBEI), a multi-billion dollar research initiative based in Emeryville, as they look beyond ethanol to the next generation of biofuels. So not only is JBEI looking at various feedstocks like switchgrass, rice, poplar and innovative ways to “deconstruct” the cellulosic material, it also attempts to synthesize fuels that work more efficiently in America’s automotive fleet, still overwhelmingly reliant on gasoline.

But even top researchers at JBEI like Jay Keasling and Blake Simmons caution that this next generation of biofuels won’t be coming online for years. Moreover, new research suggests that the net production cycle of biofuels, from the clear-cutting of trees to grow the crops to their transport to markets far away, may yield as many or more emissions as the use of petroleum-based fuel. A recent Op-Ed piece in the San Francisco Chronicle by UC Berkeley Alex Farrell cites the reason for this as primarily one of production– the way we clear land for growing biofuels, as well as our emphasis on the use of food-based crops like corn and soybean, which aren’t terribly efficient sources of ethanol to begin with.

Tad Patzek, also at UC Berkeley, has been an ardent critic of the carbon-neutral reputation of biofuels, garnering controversy for conducting studies that some other researchers have criticized for their calculations of emissions arising from biofuel production. (See Patzek’s co-authored article on page 19 of the March 2007 edition of Energy Tribune). Earlier this year, a study by researchers at the Smithsonian Tropical Research Institute suggests that biofuels are not created equal, as those made from U.S. corn, Malaysian palm oil and Brazilian soy yield more emissions than their petroleum-based counterparts, given the environmental damage they reap when grown for fuel. The study cites recycled cooking oil and biofuel made from grassy and woody cellulosic material as being more intelligent choices for cutting down on emissions.

And so the debate continues, struggling to keep pace with the technological progress made by scientists toiling away in their quest to find the holy grail of an efficient, cheap and environmentally-friendly biofuel.

Watch the “Biofuels: Beyond Ethanol” TV Story online, as well as find additional links and resources.

Sheraz Sadiq is an Associate Producer for QUEST on KQED Television.

When football fans tune in on Super Bowl Sunday next weekend, they’ll be watching a greener Super Bowl, according to the NFL. Demand for carbon credits is booming, with companies from Dell Computer to Enterprise Rent-a-Car offering their customers offsets with their purchases. But critics are concerned that consumers don’t know what they’re buying - or might not be getting what they’re promised.

The 2006 Word of the Year was “carbon netural” in the The New Oxford English Dictionary. But there’s still a lot of debate about what it means. Many people compare the U.S. carbon offset market to the Wild West. Since there is no regulation, how do you know what you’re buying?

There are several guides to carbon offsets that have been created by non-profit organizations, designed to help the average consumer (see related resources). But part of the problem is that many people are still debating what a carbon offset should be. And that’s a debate that can be found in the blogosphere.

One place you can find it is on the Grist.org blog which has many bloggers writing about green issues. Forestry offset projects, which sell credits based on the fact that trees sequester– or hold carbon dioxide, have come under fire. You can read about a few of the critiques here, here and here.

Another blog, Treehugger.com, has followed the issue as well. They posted this comparison of offset providers to help their readers do their homework and this more in depth guide on the issues buyers should be aware of.

Of course, one of the earliest debates over offsets was whether offsets would act as “indulgences”, distracting consumers from making concrete changes in their lifestyles to reduce their carbon footprint. Terrapass, one offset retailer, has tried to investigate this by surveying their customers. They found that the majority of them had already had green habits. Still, the virtues of offsets are a matter of personal opinion.

You may listen to the “Cashing in on Carbon” radio report online, as well as find additional links and resources.

Lauren Sommer is an Associate Media Producer for QUEST.

latitude: 37.325510, longitude: -120.640341