Hybrid Power for Your Home

You have access to an inexhaustible nuclear fusion reactor 93 million miles away that generates no waste or pollution. If you can picture your entire yard covered by tightly-spaced barrels of oil, that's a pretty good approximation of the amount of solar energy that falls on your property free of charge each year. How much of that heavenly gift are you grabbing?


The Futureproof Dream Home will be a hybrid powered home that taps this resource in multiple ways for 100% of its power needs (including charging the family plug-in hybrid cars). You don't need to be designing a dream home to take advantage of the power of the sun, however. The principles and the technology can be applied to any home.


Think Passive Design First


My first dream home, The House on the Hill in the Woods, built in 1985, was a passive solar design with a very well-insulated building envelope with high-performance windows. It had a shallow two-story, south-facing solarium with floor-to-ceiling glazing and a black slate floor. The rear brick wall of this space housed two special heat-storage masonry fireplaces, which provided back-up heat, if needed. In the summer time, this space was shaded by the roof overhang and deciduous trees and it was ventilated at night with gravity displacement or stack-effect ventilation augmented by a high monitor with eight large awning windows at the peak of the roof. This nighttime ventilation cooled down all those tons of masonry and kept the house comfortable without air conditioning, thanks in part to its location among tall oaks. In the winter, the sun blasted the atrium space and heated the slate and the brick as the low winter sun angle and the leafless trees turned on the seasonal solar switch automatically. The high performance windows made electric lighting unnecessary during the day while also blocking heat gain, heat loss and UV radiation. They also allowed for effective cross ventilation and great views of the wooded hillside surroundings.

Any energy productive hybrid home should first take into consideration the site, (site selection and orientation be a future post) and a high performance building envelope that uses solar orientation and passive design features to harvest free energy the old-fashioned way; the way we had been doing it for thousands of years before we invented electricity and air conditioning. The more you spend on the passive features, the less you have to spend on expensive technology like solar collectors. This is the number one secret to designing high-performance buildings for about the same cost as regular energy hogs. If you optimize the building envelope, you can downsize the systems and save money up front and for the life of the building. Forget the minimums written in your local building code in terms of recommended insulation values for walls and roofs. If you build to code, you have built the worst building you can legally build and you will pay for that mistake every month for the life of the building. In Indiana, for example, our residential energy code is based on 1992 Model Energy Code and our current commercial code is the worst in the nation (doesn't quite meet 1989 Model Energy Code), which helps explain why Hoosiers are number two on the list of states in terms of coal consumption per capita (96% of the electricity generated in Indiana comes from coal-fired power plants). For every dollar you spend on making your building more energy productive passively, you will save about three to five dollars on alternative energy systems cost. Today we have good energy modeling software to do what-ifs to make intelligent decisions about the optimal combination of insulation and glazing investment verses system costs that results in the most cost productive, energy productive investment.


Optimization also applies to things like energy productive lighting, appliances and other things you plug in. The big three in this regard are refrigeration, water heating and lighting. By choosing an Energy Star refrigerator, by installing the new and improved low-flow shower heads, Energy Star dishwasher and clothes washer, and high-performance water heater (augmented with solar and geothermal in the Futureproof Dream Home), controlling phantom loads (all those things that are turned off, but still drawing juice), and upgrading lighting (to compact florescents or light emitting diodes) you can reduce the system load by more than 60%. This makes alternative energy systems much more practical and affordable.

Let's look at some potential components of a Futureproof Hybrid Home power system beyond the passive systems described above.

Solar Hot Water

If you are looking to upgrade your current home, before you run out and buy a new solar water heater, there are some things you can do with conventional systems that will save big bucks if you don't have the cash to spend on a new system. On average, we use 60 gallons of water per person per day. Water-saving shower heads have a checkered past, but new technology, such as the Oxygenics Skin Care Shower supercharges the water stream to achieve the same wetting effect and feel as regular shower heads, with a 70% water savings. Laminar-flow aerators achieve the same effect on kitchen and bathroom faucets. Install water-saving shower heads, insulate your water heater, insulate your hot water pipes, set the water temperature at a less deadly temperature and watch your electric bill go down.

If you are building from scratch or looking for something to do with your tax rebate check, look at solar hot water. When I specified solar hot water for a new library in Newburg, Indiana, I was amazed at the production of the system in terms of heat and volume and it got me started thinking about other uses for all that free heat. More about that in a moment. For a homeowner trying to hedge against dramatic energy cost increases, solar hot water is a no-brainer. EERE Consumer's Guide to Solar Water Heating is a great resource and they will show you how a solar hot water heater can pay for itself in as little as a 18 months. If you are a heavy user of hot water, for example, if you have a large population of teenagers at home, then this could be an even faster payback. Today's high-tech solar hot water heaters perform reliably with little maintenance and they can be integrated with the architecture less conspicuously than the models from the 70s and 80s.

Geothermal Heat Pumps

A properly designed passive solar home requires little artificial heating or cooling, but if you want to have reliable back-up system, the most efficient option may be a geothermal heat pump or GHP (not to be confused with the systems that make steam from hot rocks beneath the earth in certain parts of the world). Relying on the fact that the temperature of the earth a few feet below ground remains in the mid-50-degree range all year, this system borrows heat from the earth in winter and uses the earth as a heat sink in summer.

This system can save 50 to 70 percent on your heating bill and 20 to 40 percent on your air-conditioning bill and 20 to 50 percent on total energy consumption, especially if you use a GHP that also produces hot water in summer as a byproduct of the cooling cycle. These systems can work elegantly with a radiant floor hydronic heating system or a more typical forced-air system. Initial cost is a major hump to get over, mostly for the installation of the ground loop, which requires vertical wells or horizontal trenches or, ideally, a lake or pond. There are closed-loop and open loop forms, with a close loop being the most common here. Typical payback on a GHP system is five to ten years. Federal and state and utility incentives are available for GHP systems to help get you over that hump as soon as possible and special home financing may be available. Another advantage of this system is that you move from a fossil fuel that is rapidly escalating in price to electricity, which you can make in your own back yard!

Solar Photovoltaic Power

A simple way to make your own electricity is with solar photovoltaic (or PV) panels installed on your home or on a separate structure. As this technology has improved, power output has gone up and cost per watt has gone down. New thin film solar cell technologies now entering the market promise to make PV power ever more popular as fossil-fuel power continues it's rapid rise. PVs convert sunlight directly into electricity that then typically goes to an inverter that makes that energy compatible with your house wiring. If you are powering a remote cabin or want to assure access to power during a grid power failure or have enough solar juice to refuel your plug-in hybrid car at night, you will have a battery pack that is trickle-charged by the PV system. For most applications, however, it makes sense to keep your house tied to the utility grid. If you produce excess power, you can sell it back to the utility through a process known as net metering. In 35 states, net metering laws require investor-owned utilities to provide net metering, but the actual implementation varies widely from state to state and from utility to utility and those on rural electric cooperatives may be out of luck in many areas. In Indiana, where we are bidding two net-zero-energy PV-powered library branches, net metering is only available up to a 10-kilowatt system limit and that only applies to residences and schools up to 1% of the utilities load. For businesses in Indiana, there is no net metering. In neighboring Illinois, that limit is 40 kilowatts and in Ohio, no limit is specified on either the amount or the type of user, other than no more than 1% of the utilities total load may be enrolled. A Federal net metering law is needed that would make more sense of this hodgepodge and open up the floodgates on clean technology distributed power systems development. This floodgate would really open up if a National Renewable Energy Standard is passed. Twenty-five states have renewable energy standards in place (not including Indiana). PV systems work best in bright summer sun, which is exactly the same time our national energy grid is groping for peak power. For a Futureproof Hybrid Home of reasonable size with excellent passive design, the 10 kilowatt system limit would not be a stopper, but it would be good public policy to put clean tech on a level playing field with highly subsidized brown tech, particularly in those states that lack a diverse energy portfolio, such as Indiana. Clean tech industries, a booming sector creating thousands of new jobs, are attracted to states with strong renewable energy standards, generous net metering laws and comparable incentives for clean tech development verses brown tech development.

Wind Power

Some of that energy from the sun that strikes our atmosphere is converted into the kinetic energy of wind. Wind power in Indiana is best during fall, winter and spring, while solar power is best during summer. If you can swing a hybrid wind power/PV system, you can size the solar for one quarter of the load and the wind for three quarters of the load and save on downsizing both. Wind in combination with solar also gives you more around the clock energy generation. Wind power, at least in Indiana, is a very underrated resource, especially in the flatter northern half of the state (see wind resource map). The installed cost of wind is $2 to $3 per watt, which is 1/3 to 1/2 half the cost of PV installed cost.

Because Indiana has significant wind resources located convenient to major transmission lines and major markets like Chicago, it has attracted recent investment from the wind industry and over 2000 megawatts of wind power will be put in place here in the next three years. A future drive along Interstate 65 between Lafayette and Crown Point will provide a view of hundreds of the $3 million turbines covering over 100,000 acres of Indiana farmland, which will remain farmland.

This same rich resource is available to homeowners. The drawback to small residential wind power is that the wind turbines currently available work best when they have high, steady winds free of turbulence and that requires some altitude. The rule of thumb is that the bottom of the turbine rotor should be at least 30 feet above any obstruction within 500 feet. A typical tower height for a whole-house power system is 120 feet. That could be an issue in many neighborhoods. You also need room to assemble and erect the tower. As a result, wind power is most popular in rural areas with lots of room and few obstructions. Another drawback is that wind power systems have moving parts that require service on a regular basis. This service typically occurs once or twice a year and can be done by traveling "windsmiths." If you are mechanically inclined and change your own oil, you are well-suited to do your own service (some climbing involved, unless you get a tilt-up tower).

The power of a wind turbine is proportional to the cubed velocity of the wind. In other words, a small difference in wind speed makes a tremendous difference in power output. If you put up a popular Skystream model in an 8 mile-per-hour annual average wind speed, it will generate 1200 kilowatt hours per year. The same unit in a 12 mile-per-hour average wind will provide 4560 kilowatt hours per year. Often, homeowners try to get by with a shorter tower, but wind speed increases with tower height (the commercial units are typically at 300 feet). The top three things homeowners wish they had done was 1) taller tower, 2) taller tower, 3) taller tower. The difference between an 80-foot tower and a 120-foot tower could be four times as much power with the same unit.

As a general rule, the least expensive systems are those that run at high RPM and have relatively short rotors and are light in weight. These smaller systems also tend to be the least efficient, least reliable, and make the most noise. For long-term reliability, power output and quiet, look for relatively low-speed, heavy-duty wind turbines with long rotors. To estimate the size of your wind power system you would add up 12 months of electric bills to get annual consumption, determine the portion of that annual need you wish to provide through wind power, determine your local wind speed at a given tower height suitable for your location and select a turbine based on annual output based on your average wind speed. To pinpoint wind speed in your location, you can get help from an expert or use a combination of state GIS wind maps, local airport wind data, or ideally, measure the wind resource directly with an anemometer from a local tower. The following are good resources for small wind power systems:

American Wind Energy Association

Department of Energy - Energy Efficiency and Renewable Energy - Small Wind

Wind Powering America

Midwest Renewable Energy Association

Home Power Magazine

That's all I will cover in this post, but stay tuned for information on other hybrid system components that make sense for some sites, such as microhydropower, biomass, combined heat and power and fuel cell systems.

No matter what power system you are considering, don't forget the cheapest, most productive energy is that which you don't use in the first place. If you are starting with bad passive building design, you will be wasting energy and money, no matter how exotic your power source. We'll spend another post on passive design basics. Refer also to an earlier post on Futureproof Buildings.

Can Existing Brown Buildings Turn Green?

A new study by Bethesda, Md.-based CoStar Group, which analyzed more than 1,300 LEED and Energy Star buildings representing roughly 351 million sq. ft. in the company's commercial property database, shows that not only are rents and occupancy rates higher in green buildings but sales prices are substantially higher.

LEED buildings (Leadership in Energy and Environmental Design - a building rating system administered by the US Green Building Council) are achieving rent premiums of $11.33 per sq. ft. over traditional peers and enjoy 4.1% higher occupancy rates. Energy Star buildings are commanding rent premiums of $2.40 per sq. ft. with occupancy rates of 3.6% over peers, according to the CoStar study.

One of the most persistent misconceptions about green buildings is the notion that these strategies only work for new buildings. Another is that historic buildings can't be green buildings because the effort to modernize their systems would destroy their historic value.

In reality, retrofitting existing buildings for higher performance is not only one of the most sustainable strategies, but often the most cost effective choice and certainly the fastest path to obtain the "Green to Gold" benefits of a LEED certified building.

An existing building has infrastructure in place and is more likely to be located in an established neighborhood and relate to that neighborhood's history and culture. It has an established meaning, identity, presence, sense of place and people can locate it by its name. An existing building may be old enough that it was designed in an era before air-conditioning and electric lighting, which probably means all the spaces within it have access to natural daylight and ventilation. An existing building is composed of thousands of tons of materials that have already been mined, harvested, smelted, rolled, stamped, forged, woven, baked, painted and transported to the site, then erected over many months. In other words, an existing building is a stockpile of embodied energy. A new building requires the process to start over from scratch. Existing buildings, especially historic ones, tend to be built with a level of craft and detailing in high-quality materials which is difficult to afford in a new building project budget. Their context and memory is often priceless.

For historic buildings, the greatest threat is the bulldozer driven by perceived irrelevance. Those bulldozers will be out in force as energy prices rise and older buildings that aren't upgraded and are viewed as energy hogs. Many historic buildings bit the dust for this reason during the last energy crisis. The energy crisis of the seventies was nothing compared to the one we will face in the next few decades (starting now due to declining supply, growing demand, rising population, climate change, inflation due to devalued dollar, pollution, regulation . . . but check back in a week for that post). We will all soon wax nostalgic about the current cost of fuel and electricity. We need not be nostalgic about our old buildings. We can take them with us into the carbon-constrained future and they will serve us well.

It was my good fortune to work on the Greening of the White House in 1993, which encompassed not only the White House, but the adjoining Old Executive Office Building, which is the largest solid granite building in the world (which was festooned with several hundred window air conditioners at the time). This comprehensive effort brought together six federal agencies and 100 volunteer experts to look at eight areas of potential improvement ranging from building envelope to building systems to indoor air quality to irrigation and pesticides. The resulting improvements have saved taxpayers about $380,000 per year in energy savings alone and it would a challenge any of the millions of annual visitors to point out the differences (except that the window air conditioners are gone). The OEOB was originally designed to cool itself using its own honeycombed granite mass, which took advantage of natural daylight and natural stack-effect ventilation. This design serves it well today.

The Greening of the White House led to the Greening of the Pentagon and eventually led to 12 federal agencies adopting green building standards for all of their major facilities projects, including hundreds of existing building renovations, many on the National Register of Historic Places. Two federal building renovation projects here in Indianapolis, for example, are pointing toward Leadership in Energy and Environmental Design (LEED) Silver Certification. It is the fiscally-responsible thing to do, it improves our energy security, reduces pollution, increases building valuation, improves employee health and productivity, etc,. But what about other, less famous old buildings?

When considering a green upgrade to an existing building, there are at least two options to look at to achieve a green building certification. I will briefly describe three case studies here and point you to their more in-depth case studies and other related resources.


Adobe Headquarters

Can you turn relatively new office towers, built in 1998 and 2003, green and still save money? Beginning in 2001, Adobe began to green their headquarters and they eventually certified at the highest Platinum level of LEED for Existing Buildings.

Was that a good investment for them in their relatively new building or was it all hype? Consider the numbers: $1.4 million invested in 64 projects; $384,000 in utility rebates; and here's the cool part - $1.2 million in annual operating cost savings! If you subtract the rebates, that's less than a one-year payback and a 148% return on investment. See anything wrong with that as an Adobe stockholder? If you were an Adobe employee, you would certainly notice the difference in terms of better indoor air quality, greater comfort and probably a little bump in your paycheck, or perhaps a few more employees hired because of the extra cash. Chances are they can compete for the best employees because of their state-of-the-art Platinum facility and their existing employees are more likely to show up for work, less like to use the health insurance and more likely to stick around. Workers in certified green buildings are as much as 15% more productive than workers in brown buildings. How much more do green buildings cost? Wrong question! How much more is your brown building costing you?



Gerding Theater at the Armory, Portland, Oregon - 1891 building listed on the National Register.

Photo credit: Brian Libby

This 1891 55,000-square-foot Romanesque Revival Gerding Theater Building was originally constructed to house the Oregon National Guard. A major renovation project completed in 2006, which achieved the highest LEED for New Construction rating of Platinum (53 points out of a possible 69). Among the unique features of this building is its 100' by 200' clear space spanned by Douglas fir arched trusses.

Photo credit: Brian Libby

Cambridge City Hall Annex

Even an 1871 City Hall Annex in Cambridge, Massachusetts was able to go for LEED Gold. This was a special accomplishment in light of the fact that the Planning Board and the Conservation Commission have their public meetings here. Obviously, it had to meet historic standards as well as LEED criteria.

In fact, this project won the coveted Massachusetts Historical Commission Award in 2006, the same year it won the Sustainable Buildings Industry Council's First Place Exemplary Sustainable Building Award. As a major renovation, they pursued LEED for New Construction rather than LEED for Existing Buildings.

This is one of the most energy efficient buildings in the city, due to its solar photovoltaic panels on the roof, eight geothermal heat pumps, heat recovery ventilation, low-e glazing and intelligent lighting controls. Like many 19th century buildings, this one had a head start on daylighting and natural ventilation.

So, what are you waiting for? Every business day, $464 million worth of building projects register for LEED. Your old brown building is a potential green goldmine. Don't be the last one on the block to cash in.

Meet John Picard at G Living

One of the many colorful, passionate and gifted people I met while serving on the Greening of the White House National Task Force, in 1993, was John Picard. He's aged a bit in this interview with San Francisco's G-Living TV host Sarah Backhouse, but he is still leading America's corporations down the path of green as the new black. That's black as in profit. Among his clients are Interface, GAP, Sony and now, BP. His message is timely. Why just do green or sustainable when you can go restorative?

Check out this interview, but stick around a while to enjoy many of the other videos archived at this elegant, fun and informative web site. While you are there, check out Zero House.

Gardening On High

The heirloom tomato seeds have sprouted in the peat pods in our kitchen and soon it will be time to plant them in the garden. Last year I had great success with my side yard plot which was constructed according to the book, Square Foot Gardening, by Mel Bartholomew. You construct raised 4’x4’ beds constructed from 2” x 6” lumber, throw some landscape fabric over the lawn to keep the weeds from growing through, and fill the squares with a special mix of lightweight soils and organic soil amendments (composted kitchen waste is ideal). The soil mix is designed to hold water, cutting down on irrigation requirements.

This experience has led me to speculate that a similar vegetable garden would work very well on a flat roof. If my house had a flat roof, I could have a garden roof with a view that the rabbits wouldn’t eat and I could make a productive, pleasant place to read the paper and sip coffee in my PJs while watching the dewy tomatoes grow at sunrise. I’ll put this on my list of design strategies for my next green dream home (more on that in future articles). The money view from most buildings is from the roof. That's why penthouses are so expensive.

I know what you are thinking. Conventional wisdom says that flat roofs leak and putting wet soil on a roof is insane. Conventional wisdom is a good starting point for design, because it is usually informed by past failures. History has also shown repeatedly, however, that when innovators overcome conventional wisdom with new techniques, civilization makes progress. Let’s look at some unconventional wisdom for a moment.

The technology to plant stuff on the roof is now well proven and growing quickly in popularity across the country, thanks to groups like Green Roofs for Healthy Cities spreading the word about how to do it correctly. An example of the state of the art can be found at Oaklyn Public Library in Evansville, Indiana, which supports an 18-inch deep native mesic (wet) meadow with ponding elements and a subterranean trickle irrigation system for dry spells. That must have been one dimwitted architect!

Uh, as the architect for this project (when I worked for another firm, Veazey Parrot & Shoulders, in Evansville), I can attest we did learn how to put a wet natural meadow on a library roof in 2002 and it is still dry. The meadow extends over much of the seven-acre site in which this earth-sheltered 18,500 square foot building is integrated, such that it is difficult to tell where the building ends and the site begins. In case you were wondering, it cost no more to build this earth-sheltered library. The roof is expensive but three of the walls are just buried cast concrete with no expensive exterior finishes, which allowed it to be constructed for less than the established budget and less than a typical gabled-roof library building. Oaklyn also saves many thousands of taxpayer dollars each year through reduced energy and maintenance costs. For a typical above-ground building, garden roofs do add costs and those costs escalate with the thickness, complexity and amenities. Garden roofs do have paybacks, however, that will eventually recover the initial costs in most cases. Those costs and paybacks vary with each site, garden roof type and building type. The biggest payback is often reclaimed usable space and design schools now refer to the roofscape design as the “fifth facade.”

Oaklyn inside lets in sunlight through a "Lightbridge" clerestory.

When approaching new technology, it is important to examine precedents, research best practices and find the best experts. It didn’t take long for us to find the complex garden roof of Chicago City Hall and the designer of its complex garden roof, Charlie Miller, president of Roofscapes, who is one of the world’s premier experts on garden roofs (also known as green roofs or vegetated roofs). Working with Charlie and the rest of the design team, we figured out a way to pull that off. This “particularly robust” national-award-winning garden roof is designed to last for 50-75 years before replacement. It also makes the building more energy efficient, helps with stormwater mitigation, and the earth-sheltered strategy makes good use of an otherwise almost unbuildable hillside site. I would consider a similar, but less complex system for my dream home edible roof garden design. But Oaklyn is a good example of some of the technology available for less ambitious projects. Let’s go through some of the basics.

A growing medium that will support vegetables will need to be at least five inches deep to emulate the Square Foot Garden that occupies my side yard. The weight of five inches of wet soil needs to be added to the normal structural calculations. This would be known in garden roof language as an intensive system, as opposed to an extensive system, which typically are 3 to 4 inches thick and can go where you may already have a gravel ballasted roof. Ford Motor Company has a very large example of an extensive system at their River Rouge Plant. The Indianapolis Museum of Art (by BDMD Architects) has a new parking garage covered by a very intensive system that supports an allee with large trees. Other commercial garden roofs feature pools and fountains or even a full golf course hole. It is a way to reclaim expensive urban space. Chicago is bullish on green roofs because they cool the city and reduce combined sewer overflow issues. They now have 300 garden roofs throughout the city.

Eleven-foot tall windows help daylight earth-sheltered Oaklyn Library.

Oaklyn Library used a composite concrete deck (where the poured concrete locks into a specially-designed corrugated metal deck and both are strengthened) to support a very deep garden roof. A concrete deck would probably not be necessary on a residential garden roof, but it may be a good choice if you are using cast concrete walls, which would be a great way to go on a home for other reasons (more on this in a future article). Larry Crane at Crane Builders uses this type of system to build floors in his multi-level insulated concrete form (ICF) walled homes. With typical wood-framed construction, garden roof capacity could be achieved with deeper joists, parallel chord trusses or engineered wood microlam or glulam beams or with I-joists. On existing homes, it would probably mean sister joists, but be sure to check with a licensed architect or structural engineer before doing anything on your own. There are other considerations, like lateral loads in earthquakes, to consider, depending on your location and loading capacity of your walls and foundation.

Corporate roof golfing!

Many existing buildings, including the building I work in, already have the structural capacity for garden roofs as they were constructed in such a way as to be added to later and the roof was actually designed to be a heavily-loaded industrial floor. Reclaiming such space for use by people, instead of leaving it to the pigeons and the rooftop compressors, has become a hot niche market for many firms.

When you have the structure confirmed, the key decision is what type of membrane to use to keep the elements out of the building. For Oaklyn, the choice came down to two systems; a liquid-applied membrane by American Hydrotech and a heat-welded reinforced PVC sheet membrane system by Sarnafil. Both systems had been proven in very high profile projects around the world and either probably would have worked. Sarnafil allowed for the incorporation of ponding elements (plastic pipe dams heat-welded into a secondary protective cover sheet), which was also heat welded. Oaklyn’s roof system is “robust” in that is has two layers of heat-welded, reinforced PVC membranes, the primary layer and a protective layer. This type of membrane has been used in underwater tunnels and has a thirty-year history in Germany. This membrane is also impervious to root growth, while most organic materials require some type of additional root growth barrier. To prevent excessive ponding of water that would kill the meadow, Oaklyn’s roof has a slight slope and a subterranean drainage system consisting of low-profile rectangular perforated drain pipe. The overburden of soil protects these premium membranes from ultraviolet light, extreme temperatures and physical damage. Welds are tested prior to adding soil mix by flooding the roof for 24 hours. Another advantage of a heat-welded sheet membrane is that the same system can be used to flash penetrations, parapet walls, and other interruptions where leaks are most likely to occur in any roof system. Sarnafil also has certified installers, which means you get experienced crews who know what they are doing. It is also a good idea to compartmentalize sections of the roof and embed electronic leak detection so that any eventual problems can be discovered before any damage is done and repairs can be made without removing large sections of overburden. Consider this cheap insurance.

Garden roof technology continues to improve rapidly, with new developments like pre-planted trays for rapid starting of the living part of the system. Live Roof seems to be leading this trend.

Sixteen species made up the initial meadow planting at Oaklyn Library

Oaklyn used plugs of living meadow plants in 16 species. The key consideration for roof gardens is whether they will be accessible and frequently maintained, like a vegetable roof garden, or if they will have to fend for themselves without much maintenance and without irrigation. In the latter category are plantings of sedums and mosses that can survive extreme conditions normally seen on rooftops without irrigation.

Getting back to a garden on your home roof; some of the advantages, other than more usable outdoor space, include: increased energy efficiency, sound isolation, disaster resistance (fire, hail, high winds), significantly longer roof life, less stormwater runoff and a supply of very fresh food. Aesthetically speaking, this will work best when the building is already designed in an architectural style that features a low-slope roof. My guess is your subdivision's covenant would prevent you from lopping off your massive neo-French hyper-hip roof that matches those of all your neighbors. This would be great in an urban setting, however, when you don't have much of a yard or garden space on the ground plane or on a contemporary-style custom home. For a design from scratch, you would have the option of raising the garden to the roof, or, if you have a nice south-facing slope with a view, put the house under the garden. Since you have all that new flat landscape, you may also want to put some solar hot water panels and solar photovoltaic panels up there to wipe out your electric bill and charge your electric car. More on that later as we continue to explore the green dream home.

What To Do When Your Left Brain Shuts Down?

Indiana native and IU School of Medicine neuroanatomist Dr. Jill Bolte Taylor recently made the big time as a speaker at the TED conference in Monterey, California. This is no ordinary professional conference and Dr. Jill Bolte Taylor is no ordinary brain scientist. Imagine you are a Harvard-trained expert on brain function and your own brain suddenly experiences a massive stroke that essentially shuts down the left side of your brain. Her story is one that transcends biology. Watch her dramatic 18-minute presentation that received a rousing standing ovation and that has been widely recognized as one of the most powerful of the many earthshaking presentations in the remarkable history of the TED conference. Hang around and view more of the presentations. Prepare your own $100,000 idea worth spreading for the next TED Prize.

Dynamic Virtual Design

A well-designed and constructed building should last for a century or longer. Design decisions last for generations, but they are often made with little more than guesswork. Experienced architects eventually learn from their mistakes, but those mistakes tend to outlast the architect. A better approach is to model the building in detail during early design and tweak the design to optimize the building's performance. When you optimize a design, you make it work better for less money - for a very, very long time.

Sun Path Diagram for a net zero energy public library (analysis by Nick Worden and Daniel Overbey, BDMD Architects - Green Dream Team)

With the advent of sophisticated computer modelling software, it is possible to get an accurate idea of how a building design will perform long before the building is constructed. A good suite of modelling software can tell you:

• How much ambient light will be provided by natural daylight on December 21 on a cloudy day?
• What is the effect of adding wall or attic insulation on the size of the heating and cooling system?
• How many photovoltaic panels will I need to balance the energy needs of this building on an annual basis? What if I changed from fluorescent to LED lighting?
• What size of clerestory windows will allow the best natural ventilation and will all parts of the building be adequately ventilated?
• Will the building next door shade the solar panels on my building?
• If I put a white roof on this building instead of a black roof, how does that effect my heat gain and heat loss for the year? What if I put on a vegetated roof?
• How much energy will this building use and what will it's carbon footprint be?

Many architects today still use pencil and paper and build physical models (if any), but a growing number are moving to 3D software that allows a design to be "built" in the computer before it is built in the real world. One 3D modelling software program that anyone can learn to use is SketchUp, which provides some rudimentary evaluation tools, such as simple shading analysis. There are also add-ons to export these simple models as green building extensible markup language (gbXML) files which can then provide the basis for detailed energy and building performance analysis with energy, ventilation and daylight modelling software.

Daylighting analysis for a net zero energy public library showing daylight levels on a cloudy day in the middle of winter in Cass County, Indiana. (analysis by Nick Worden and Dan Overbey, BDMD Architects - Green Dream Team)

To get more accurate modelling data, however, sophisticated building information modelling (BIM) programs like AutoDesk's Revit Architecture are typically used. This software helps architects visualize the design but it also can help determine how well its systems will function. When the whole design team utilizes these tools during early design, little effort is wasted on guesswork. The computer model removes the guesswork and informs a more dynamic and accurate design process, which leads toward a more successful end.

I've been impressed with a relatively inexpensive analysis tool called ECOTECT from Square One Research, which generated the images in this post. Another interesting analysis tool is Green Building Studio, which is about to be acquired by Autodesk, which means it will probably cease to be free. GBS can do a whole building energy analysis of your model when you export it and upload it in gbXML format. GBS can also export to popular engineering energy analysis tools like DOE-2, eQuest, EnergyPlus and Trane Trace700, which can provide energy performance data for any hour of the day any day of the year.

We are finally entering a time when architecture is no longer just a fashion show. We want our buildings to look great and we want the experience of the architecture to be elevating, but we also want them to PERFORM! Green buildings perform by delivering delightful, healthful, daylit, comfortable spaces that are energy and resource productive. The best way to get there is by means of a dynamic collaborative design process assisted by state-of-the-art design tools that can tell us how well the building will perform before the shovels hit the ground and before you open your first utility bill.

In Defense of Michael Pollan

When my wife and I saw that author Michael Pollan would be speaking at Butler University near our home, we immediately marked it on our calendar. He has had my attention since The Botany of Desire (2001 Random House), but his The Omnivore’s Dilemma (2006, Penguin Press) began to change our eating habits. We just finished his latest book, In Defense of Food (2008 Penguin Press), and that was the basis for most of his talk this past week. We weren’t the only ones in Indianapolis who are apparently avid Pollan readers. Atherton Hall was filled a half hour before his talk and university officials quickly opened another lecture hall linked via closed circuit broadcast.

Pollan began his lecture with the words that opened his latest book, with the advice to “Eat food. Not too much. Mostly plants.” Then he developed his convincing case for that recommendation. He described the irony that we live in a country where millions of people are suffering from obesity and malnutrition at the same time. Food-related diseases like Type II diabetes and obesity have become so common as to create new “lifestyles” with their own magazines and supportive industries. These “Western Diet” diseases have similar effects in other countries as the impoverished increase their incomes to the point where they can afford to consume American-style processed food. Wherever our food goes, so goes our lethal food-related diseases.

"Eat food." The test for this is to eat only that which your grandmother would recognize as food. That would probably not include spray imitation “cheese” in a can, for example. The shorter the ingredient list the better. One unprocessed ingredient is ideal. Much of what we eat is so highly processed that most of the nutritional value is missing and we are left with little more than the calories and chemicals. Pollan recommends staying out of the center of the store and sticking to the whole foods on the outside of the store. The best food has no health claims or even labels. Think vegetables and fruits and other real whole foods. Better yet, get your food from the local farmer’s market or your own garden. Yes, that means you may need to relearn how to raise a garden and cook, but the rewards of unadulterated fresh food are worth the effort.

"Not too much." This is pretty obvious, but he notes that we eat more than our healthier counterparts in other countries, such as Italy, where eating is a slow, social process with smaller servings that are more mindfully consumed over a much longer period of time. In our fast food nation we tend to eat so much so fast that we overshoot our signals of satiation and miss a lot of food appreciation along the way, not the mention the loss of the family sit-down meal. Pollan cited an unbelievable statistic that 20% of American meals are consumed in cars.

"Mostly plants." Numerous studies, notably The China Study, by Collin Campbell, have shown that consuming a diet that includes a significant portion of animal products, especially red meat, can lead to health problems ranging from heart disease to cancer to premature puberty in girls. In those populations where the diet is all or mostly plants, these diseases are virtually nonexistent and people enjoy longer, healthier lives. Pollan recommends consuming free range or wild animal protein, if any, to avoid the health problems associated with meat produced in confined industrial farm operations with unnatural diets that require massive doses of antibiotics augmented with growth hormones.

The bonus of an organic, local, plant-based whole food diet, other than better eating and personal health and longevity, is significantly reduced environmental impact. A 408-page report by U.N scientists, Livestock’s Long Shadow, indicated that raising animals for food is responsible for more greenhouse gases than all vehicles in the world combined. More than 260 million acres of U.S. forest have been cleared to create cropland to grow grain to feed farmed animals; farmed animals are fed more than 70 percent of the corn, wheat, and other grains grown in the U.S.; and almost half of the water and 80 percent of the agricultural land in the U.S. are used to raise animals for food.

So what is it like to really veg out? We have been learning to prepare whole plant foods from our garden, from the local farmers’ markets, from our local whole foods stores (and the mainstream stores increasing their whole foods selections) and from our local farm delivery service for the past six months and it has been a journey from the artificial and the bland to the real and the delicious. We have learned how to cook again and we have learned to appreciate our food and our experience of food more. We can enthusiastically report that it has been a very pleasant adventure in better foraging, tastier food and a more relaxing dining experience. The fact that we have also significantly reduced our carbon footprint is a huge bonus.

It was no surprise that we had trouble finding a seat at Butler’s Atherton Hall to hear Michael Pollan and it is no surprise that In Defense of Food is #2 on the New York Times Bestseller List.