Assorted Links

A home in Berkeley is the first in California to have permitted interior use of rainwater.

A new British law imposes fines for landlords renting out energy-inefficient property.

Transportation Secretary Ray LaHood talks about livable communities.

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Upcoming Webinars

I just want to remind folks that we have launched a “Webinars” page to feature interesting online presentations. You can navigate to the Webinars page using links at the right side of the blog.

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November 10, 2010 (Wednesday)

Pacific Energy Center: “Chris Hammer – What’s Behavior Got To Do With Energy Efficiency?”

6:30 pm – 8:00 pm

We often look to technology to capture energy savings. What about the behavior of individuals in the home and workplace? Chris Hammer will describe occupant actions that save energy, discuss social science research on behavior and energy, and review case studies of organizations that implemented behavior change programs.

Free event. For more info and links to register here.

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November 18, 2010 (Thursday)

Build It Green: “Passive House – A Sustainable Building Revolution in California”

11:00 am – 12:30 pm

Expectations for building occupant comfort, health and efficiency are increasing simultaneously. The Passive House standard meets all of these requirements at once. By producing buildings with energy demands that can be met at a renewable scale of production, Passive House can future-proof our communities and put California on track to meet our greeenhouse gas emission reduction targets. The future of building is here!An in-depth look at the Passive House standard by the leading local experts in the field, this webinar will:

  • Detail current retrofit and new construction Passive House projects and approaches in the Bay Area
  • Retrofit lessons learned and phased approaches
  • Illustrate how Passive House meets or exceeds the California Energy Efficiency Strategic Plan, and makes net-zero and energy-positive buildings feasible TODAY in the most cost-effective way possible
  • Explore how the Passive House standard can integrate with and enhance GPR and other green building rating systems.

Free for Build It Green members, $10 for non-members – more info and links to register here.

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Alex Wilson, Founder of EBN – Part 3


On Tuesday, September 28, I was in the audience at the Pacific Energy Center in San Francisco as Alex Wilson, Founder and Executive Editor of Environmental Building News, gave a presentation about misguided pursuits in green building. He covered all-glass buildings, building-integrated wind turbines, and residential ground source heat pumps.

The post below consists of Part 3 of my record of the presentation – residential ground source heat pumps. All portions are included in chronological order. Read Part 1 here. Read Part 2 here.

An ellipsis (…) indicates that I was not able to capture the words or thoughts skipped. The presentation is transcribed as accurately as possible – punctuation choices are mine.

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Let me move on the last issue – this is more at the residential scale. I’ve been frustrated for a while. This issue first struck me when I was a juror for a design competition maybe 10 years ago … almost without exception, these homes had ground source heat pumps. They went to extraordinary lengths to reduce heat loads…yet they didn’t benefit from that on the cost side by reducing the cost of the heating systems.

Ground source heat pumps are great … They can move heat from outside a house to inside, even if it’s colder outside than inside. That’s how a refrigerator works … does it by changing phases, alternately compressing and expanding the refrigerant …

Okay, so on the surface they’re very attractive, but they’re expensive. Let me explain the difference between an air source heat pump and ground source heat pump. Air source uses the air as a heat exchanger. Ground source uses the ground, which is more of a constant temperature during the year … if you’re heating, you want as warm a source as possible. The heat pumps can be operating in reverse in the summer to provide cooling. That’s the theory of why a ground source should be better than an air source heat pump. But there’s a lot of cost … either digging wells or trenching pipe … the costs are pretty high.

In our area in New England, we’re seeing ground source heat pumps for residences for about $30,000 … … As with wind turbines, there’s remarkably little data on the performance of ground source heat pumps. I don’t mean lab data, but actual in situ performance. There was a study just published by The Energy Saving Trust in the UK that compares ground source heat pumps with air source heat pumps. The results are pretty interesting … … There’s a pretty dramatic range in the performance of these systems … the range of performance is pretty identical, ground source to air source. That’s pretty interesting because air source is a lot cheaper to install. If you’re planning to spend a bunch of money on a heating system, you should instead take most of that money and invest it in the envelope and get the heating load down so low that you can meet the heating load with whatever system you want … A very efficient home can be heated with a few strips of electric baseboard heat or a small pellet stove … instead of a very expensive system. It’s the same argument I have about radiant floor heating systems– it’s a great way to distribute heat for a lousy building … I digress.

The basic argument with ground source heat pumps is take the money and put it into the building envelope. If you want a heat pump, get an air source heat pump …. these can be put in for a lots less money than ground source heat pumps. The performance is now neck and neck, and the performance of air source heat pumps keeps going up … I actually predict that the ground source heat pump industry disappears in the next ten years, it wouldn’t surprise me at all …

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This exchange was followed by a question and answer session with the audience.

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Part 1 is posted here. Part 2 is posted here.

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Water Footprint Calculator


The National Geographic website has a water footprint calculator that walks you through very basic aspects of your lifestyle and give you a sense of how much water you use at home, to produce your diet, to produce the stuff you buy, and to produce the fuel you need to travel. And it compares your use to the American average for each category. Check it out here!

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Assorted Links

In Cleveland, Ohio, recycling bins with microchips will prompt inspections and potential fines if not used properly.

General Electric thinks it can cut home energy use by 70% in pilot projects with the DOE Building America Program.

Ride-sharing programs consider how to use mobile devices to expand to new audiences.

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Houses – Small, Reused, and Prefab


A number of interesting house-related tidbits came my way this week, and I wanted to share a few favorites…

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NPR featured a story (with photos!) about incredibly tiny Japanese houses designed to fit on slivers of land. Every function and element has to be carefully considered.

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Mother Earth News featured a story about how some folks are reusing round, metal grain bins (also called grain silos) as houses. One architect, Mark Clipsham, specializes in putting one bin inside another (with a crane) and then filling the space with foam insulation to improve thermal performance – there are photos of his work here.

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And Treehugger featured a story about Michelle Kaufmann’s new “Zero” series of prefabricated homes. Her company is based in the Bay Area. Her website goes into more detail about the homes, and lists the “lessons learned” from her previous ventures into prefab, which are incorporated into this venture:

  1. Minimize button up work / maximize what is done off-site
  2. Have a system that can offer both efficiencies with repetition in module types, but designed to offer a great variety of overall configurations so each home can be uniquely composed for the specific site conditions and client goals.
  3. Use materials and systems that have been researched and tested for the optimal balance of beauty, longevity, sustainability and cost
  4. Maximize efficiencies in dimensions of materials by designing to construction and shipping “sweet spots” to reduce waste and costs

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Editorial – How Much Space is Enough?


Houses have been getting bigger. Over the past fifty plus years (until 2008), the size of the average new house more than doubled, from 1,000 square feet or less in 1950 to 2,265 in 2000 (values from NAHB). The percentage of new homes smaller than 1,200 square feet has been dropping since 1987, while the percentage of new homes larger than 2,400 grew from 21% to 38% between 1987 and 2001 (values from this study). Interestingly, the size of the average new home dropped in 2008 (data here and an article here).

The general trend of larger and larger houses has a direct impact on the environment. Larger houses require more land to build on, more materials for construction, more energy to heat, cool, and light, and result in more waste, both during construction and demolition. While it is expected that there may be some “economy of scale” as houses get larger, there is a widely held suspicion that larger homes consume proportionally more materials because they often have higher ceilings and more complex geometry. Larger houses also require more materials to furnish and decorate.

It should be noted that larger homes are not only increasing in area (square footage); they are also increasing in volume, which may ultimately have a larger impact on the energy consumption of the house. Larger houses are usually constructed with extra features that are not surface area efficient (such as complicated roofs and dormer windows) and which consume more energy for heating and cooling than a compact house of the same volume.

New houses should be both smaller and more compact.

However, it has been difficult to build smaller homes. Aside from the social cache afforded those with larger homes, zoning rules and mortgage practices have also pushed “bigger is better.” For example, mortgage lenders often required the home to be “three times the value of the land,” which then determined a minimum house size for a certain area.

The recent, slight tilt towards smaller home is likely due to the recession and the constrained finances of those building, financing and buying homes. But it is encouraging. When considering what they could afford financially, people chose smaller houses. If we consider what we can “afford” using metrics of energy, water, and materials, we should prioritize building smaller houses.

Anna’s Links – 5/26/10

A round-up of interesting (and depressing) analysis of the recent oil rig explosion and oil spill…

A “live” feed of the BP oil spill is now posted online (though traffic has been so high that it’s not always possible to view) – U.S. Energy and Commerce Committee.

Experts examining a previous video of the oil leak released by BP estimate that the size of the oil spill is much larger than official estimates – NPR.

Scientists fault the government for “failing to conduct an adequate scientific analysis of the damage and of allowing BP to obscure the spill’s true scope” – New York Times.

Some experts are starting to say that the oil leaks could last for years because “we don’t have any idea how to stop this” – National Geographic.

Aerial photos of the Gulf oil spill show its vast size – NASA Earth Observatory.

A scientist at Lawrence Berkeley National Lab notes that some of the detergents used to clean up spill sites can be more toxic that the oil itself – Lawrence Berkeley National Lab.

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Other interesting tidbits from the web…

Two campuses of the University of California system, Berkeley and Davis, have been given  MacArthur grants to launch a new master’s degree program in sustainable development practice – UC Berkeley and MacArthur Foundation.

Developers in Las Vegas are cranking up their sales pitches for brand new homes again, even though the city has 9,500 empty houses and another 5,600 that were repossessed in the first quarter of 2010 – New York Times.

Las Vegas as a whole has been very dependent on growth and construction – the recent drop in new construction had a major impact on municipal funding – Aguanomics and Bloomberg.

Federal officials want public input on a proposal to revise policies for managing urban water shortages in the Central Valley – meetings will be held in Sacramento on May 26, June 23, July 20, and August 19 – The Sacramento Bee.



This post is part of our definitions series on “eco-lingo” and technical terms.

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I am not (and have never been) a Bay Area homeowner, which is perhaps why I was not very familiar with the term “RECO” until recently.

There are many well-publicized programs aimed at making new buildings as “green” and energy efficient as possible. These efforts are viewed as integral to efforts to reduce future energy use and combat climate change. But in many places, we’re mostly stuck with the buildings that we’ve got. And we’ll likely be stuck with them for many years to come. So how do we influence and improve the energy and water performance of these buildings? One answer is a RECO.

Residential Energy Conservation Ordinance (RECO)

The purpose of a RECO is to improve the energy (and now water) efficiency of housing stock at the point of sale and major renovation.

In Berkeley, CA, the majority of the housing stock was built before the introduction of state building energy codes.  The buildings are often drafty, with no insulation and single-pane windows. Further, more than half of the city’s housing units are occupied by renters. In rental units landlords must approve and often conduct and pay for any major energy retrofits. However, the retrofits primarily benefit the renters, who pay the utility bills. Because of these split incentives, an obvious point of intervention to improve the energy efficiency of the existing building stock over time is at transfer of ownership or major renovation. The Berkeley RECO, which has been in place since the 1980s, applies to all residential homes and units, whether single-family homes, condos, multi-family properties, or live-work spaces, and requires that the home or unit comply with specific energy and water performance measures at the time of sale or major renovation.

The Berkeley RECO has ten prescriptive measures covering toilets, showerheads, faucets, water heaters, hot and cold water piping, exterior door weather-stripping, furnace ducts, fireplace chimneys, ceiling insulation, and lighting in common areas (for multi-family buildings).

It is tempting to say the measures are not enough, that much more drastic intervention (and more quickly) will be needed to achieve dramatic energy savings. This is probably true. But many approaches will be needed, and the gradual but consistent improvement of existing housing stock is a good place to start.

Since 1994, Berkeley has also had a Commercial Energy Conservation Ordinance (CECO).

Participants in Berkeley FIRST (Berkeley’s solar financing program) have to comply with RECO/CECO.

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What exactly does “sustainability” mean? How about “green”, “eco” or “environmentally friendly”? The truth is that these terms are just vague enough to mean many different things to many different people. With the staggering array of “green” products, ‘lifestyles’ and concepts being promoted by marketers and environmentalists alike (as well as the necessary coining of new terms to match new ideas) our definition series aims to make sense of the rising tide of “eco-lingo” and technical terms.