Monday, June 30, 2008
An academic pursuit providing real world results
This luxury house won an NAHB Energy Value Housing Award (Gold) while also complying with several sets of standards including LEED, Environments for Living and ALA HealthHouse. It was designed to be healthy, durable and affordable - as should be the goal of any sustainable building. Every detail was carefully considered, making the home efficient to build as well as live in. Pre-manufactured components sped construction; thoughtful planning minimized site disturbance and preserved existing vegetation; meticulously installed insulation, a tight building envelope and a rainwater collection system minimize energy and resource demands. Methodical preparation and execution are likely responsible for this project’s high marks, but something else also makes it unique - it was built by university students.
At Yavapai College, in Prescott, Arizona, the Residential Building Technology Program immerses students in both the theoretical and practical sides of high performance homebuilding. Director Tony Grahame leads each class through every stage of design and construction to the completion of a marketable home. The students learn not only about the necessary integration of a building’s parts, but also about the cooperation that is necessary to make that building happen.
Although its source of labor may be atypical, this project is a great example of how smart design can facilitate increased sustainability within a typical budget. Some of the methods and materials used might have been new to the RBT students, but the guidance they received gave them an edge over experienced contractors without green building training. This point was clearly made by an NAHB Energy Value House judge’s comment - “if only every house built in the U.S. could have the oversight of this project - all of our houses would be energy efficient and durable.”
Builder: Yavapai College Residential Building Technology Program, Tony Grahhame Director
Architect/Designer: Yapavi College Architectural Design Students and Staff
Location: Chino Valley, Arizona
Cost ($/sf): $90/sq.ft (not including cost of student labor)
Size: 3202 sq.ft.
Foundation type and R-value: Combination - slab on grade xps foam at edge (R-5), crawlspace ICF (R-16), basement integral XPS and blown in cellulose ((R-26.5)
Wall construction and R-value: 2x6 @ 24” o.c., 2” XPS and 5 1/2” unfaced fiberglass batt (R-29)
Windows: Double pane, low-e, argon filled. SHGC = .30 - .59; U- factor = 0.30 -0.35
Roof construction and R-value: Engineered trusses, blown-in cellulose (R-38)
Garage: Thermally and pressure isolated from living space
Conditioning equipment : 14 SEER AC system, 56,672/80,960 BTU dual stage direct venting gas furnace
Water heating equipment: Solar domestic hot water
HERS Rating: 90.5 (5 star +)
Water efficiency measures used in this project
· Low flow toilets, faucets and shower heads
· Water conserving dishwasher
· 1250 gallon rainwater collection system
· Gray water distribution system
· All hot water taps within 30ft. of hot water storage tank
Energy efficiency measures used in this project
· Whole-house Energy Star interior and exterior lighting package with CFL bulbs.
· Extremely tight building envelope (blower door test 0.96 @50 Pascals)
· Roof overhangs optimized for summer window shading and winter solar gain.
· Energy Star appliances including dishwasher, ceiling fans and ventilation fans
· Sealed ductwork, leakage measured at 0cfm @ 25 Pascals
· All ductwork is located within the conditioned space
Green materials and/or resource efficiency used in this project
· Decking, ICFs, wall and ceiling insulation all include recycled content
· Recycled cardboard and metal construction materials
Indoor air quality measures used in this project
· Balanced whole house air exchange system with MERV-10 and HEPA filtration
· All construction materials contain low or no VOC
· Low formaldehyde content in particleboard cabinets
Alternate Energy Utilization
Photovoltaic power: 2 KW
Solar water heating: 40.9 sq.ft. panel, 80gallon storage tank
--Rob Wotzak is Assistant editor at GreenBuildingAdvisor.com. Photos by Tony Grahame
Monday, June 23, 2008
Architect by accident, advocate by design.
When I was about 11 years old, I volunteered at my town’s first, newly opened, recycling center. A couple of years later, I helped clean scores of seabirds that had been fouled with oil from the 1969 spill off the Santa Barbara coast. That summer, I had my first (glorious!) back country experience, in the High Sierra near Lake Tahoe. Many more backpacking trips followed that one, summer after summer. Those early experiences, an innate abhorrence for waste, and parental influence (I was the child of two activist English teachers – my father a far-left radical and my mother a deeply committed social welfare advocate) forged in me a reverence for nature and a powerful drive to protect the natural world that has never been far from the surface.
In college I studied architecture. However, by sometime early in my third year, or maybe sooner, I was pretty sure I didn’t want to be an architect. I had no clue what else to do, though, so – knowing that a B.S. in architecture from Cal Poly would be a good meal ticket – I stuck with the program. My salvation was senior year abroad, in Florence, Italy. There I acquired a deep appreciation for development patterns that worked, in marked contrast to most American cities, and started to become aware of the huge negative impact of the automobile on human settlement.
After my Italian year and graduation in 1978, I found I had little interest in practicing architecture (the only architecture firm at which I interviewed designed gas stations!). And so I stumbled into technical editing and then writing, where I stayed for a number of years. I moonlighted, too, doing occasional remodeling projects, getting jobs by word of mouth. I never interned, never earned an architecture license. Over the years, though, I did learn quite a bit about how houses go together. I also became troubled by the amount of waste in my industry.
In the late 80s I began to hear about healthy building and ecological building, and eventually resolved that was where I belonged. Knowing that without external structure I wouldn’t acquire enough knowledge, quickly enough to suit me, I went back to school, enrolling in the Master of Architecture program at UC Berkeley in 1993. Since then, I’ve been completely immersed in green building (which, back then, really didn’t have a name).
My first job in the field was researching and writing for the Wood Reduction Clearinghouse, a project spun out of the Rainforest Action Network. From there I went to the Natural Resources Defense Council, where I wrote a book, Efficient Wood Use in Residential Construction: A Practical Guide to Saving Wood, Money, and Forests. Shortly thereafter I was tapped to be part of the USGBC’s effort to develop a national standard for residential construction – LEED for Homes. After two years chairing the LEED for Homes Materials & Resources Technical Advisory Subcommittee (MR-TASC) I became the co-chair of the LEED for Homes Committee, a seat I held for four years, until the program went into pilot. At that time I stepped down (while continuing to serve on the committee and chair the MR-TASC) in order to devote more time to implementation efforts. In the two-plus years since the launch of the pilot, I have taught hundreds of people about the LEED for Homes program and consulted to the LEED for Homes Provider in CA and to scores of developers, homeowners, production and custom builders, local governments, private investors, product manufacturers, and others who have wanted to better understand how to tackle the complex field of green building. It has been – and continues to be – a wild, exciting, and vastly rewarding ride, above all because of the amazing caliber of individuals with whom I work, and their remarkable unity of purpose.
By Peter Yost
There are few green building topics that produce more frustration and uncertainty than claims about the environmental footprint of particular building materials. Life Cycle Assessments, such as the ones listed below, seem like the perfect tool for summing it all up, but Life Cycle Assessments fall short for many reasons.
Getting reliable data is difficult at best
A life cycle assessment starts with a life cycle inventory. This means identifying and quantifying the inputs and outputs of a product from “cradle to grave” (mining, manufacturing, moving, installing, service life, and disposing of). This is no small task. And because much of the information comes from product manufacturers, the data can be incomplete -- manufacturers may not have all of the information or they may be unwilling to share it. When all products in a Life Cycle Assessment database are not scrutinized equally, conclusions drawn from the information may be misleading.
You can’t predict how many people will actually get cancer, only that a product could cause it
After the life cycle inventory is put together, it must be translated it into actual environmental impacts: global warming, human toxicity, ozone depletion, rainforest degradation, etc. This is called life cycle impact assessment (LCIA), and it gets pretty hypothetical. Many of these environmental effects require assumptions, such as how many lives will be lost from a particular cancer-causing output. These assumptions are impossible for normal people to evaluate, so we have to rely on someone else’s professional judgment.
They make apples to oranges environmental comparisons
The environmental impacts associated with a product are wide-ranging and measured in many different ways. For example, biodiversity may be gauged by the number of species going extinct and global warming by world-wide temperature rise. But how do we compare the two in relative importance? Again, it’s hard for normal people to evaluate the relative importance, so we must rely on trustworthy experts to weight each impact category in essentially an “apples to oranges” process. Is ozone depletion twice as important as the acidification of lakes? Pick your poison.
Setting boundary conditions is subjective and fuzzy
In any analysis, deciding what is on the table and what is out of bounds or beyond the scope is an essential first step. What does this mean in environmental life cycle assessment of building products? Three vexing examples provide valuable insight:
- Open cell spray foam appears very green -- it insulates and air seals, it has no VOC off-gassing, uses water as the blowing agent, and it has proven to quite durable. But when considered in the greater context of a building, its excellent adhesion makes recycling or reusing the wood to which it is stuck difficult or even impossible. Should the insulation/air sealing properties be evaluated alone or should the effect on other building materials be considered?
- Burning PVC is very bad -- when burned in uncontrolled conditions, PVC creates a serious environmental hazard. But if PVC waste from construction is rarely involved in uncontrolled burning, should this issue be included in the environmental profile of PVC plumbing pipe? Should burning be included in other PVC products, but not those used in construction?
- Environmental regulations in other countries are often more lax that ours: A global manufacturer of paints has a good record of environmental compliance in the US, but a lousy record in countries with lax environmental standards. Do we consider the environmental degradation in other countries if we know the paint we are using is produced in the US?
Life Cycle Assessment is not a waste of time
Does this mean that Life Cycle Assessments and trying to compare the environmental profiles of competing products is a complete waste of time? Does it really matter which products we use from an environmental standpoint? The answer is that the environmental footprint of a product matters, but It should be put in the proper context:
- Product selection should be among the last of the green building priorities. The energy efficiency, water efficiency, durability, and safety to human health of the building should be the top priorities.
- Use building products manufactured and/or assembled locally and optimize the use of all construction materials (use fewer studs, design in 2 ft. modules, etc.).
For the more complex LCA issues, go with product recommendations from a 3rd party, transparent, expert-based system such as TK.
Life Cycle Assessment for Buildings: Seeking the Holy Grail
Environmental Building News, March 2002.
Life Cycle 101
US EPA Life Cycle Assessment Research
Life Cycle Assessment tools:
- A Sampling of LCA Tools (sidebar to the above EBN article)
- BEES -- Building for Environmental and Economic Sustainability tool published by the National Institute of Standards and Technology
- The Athena Institute Environmental Impact Estimator
- Pharos Material Evaluation tool
--Peter Yost is Residential Program Manager at GreenBuildingAdvisor.com
Friday, June 20, 2008
By Michael Chandler
I've been building solar and green for thirty years and have built homes that Energy Star certify at 76% more efficient than code and score gold on our North Carolina Green Building Program as well as NAHB’s green building program but I have never built a house that would qualify for even basic LEED-H certification and it doesn't seem likely that I will unless I get a client who specifically requests the LEED-H program over the alternatives. The reason for this is that my homes use oversized ductwork with air flow controlled by butterfly dampers and the LEED-H program requires that airflow be controlled through implementation of ACCA Manual D duct design.
What's the difference between Manual D and Manual J?
There is some confusion in the market about the difference between Manual D, which sizes ducts to best match the equipment and needs of the rooms served, and Manual J, which sizes the equipment to match the actual projected load of the home (and is a basic minimum requirement of Energy Star and most Green Building Standards including the NAHB/ICC National Green Building Standard.) The Manual D duct design standard forces HVAC installers to use 4" insulated flex for smaller rooms and 6" for medium sized rooms and 8" for larger rooms. In my market it’s calculation and implementation adds significant cost to the HVAC system especially on smaller, one-of-a-kind homes that LEED-h is hoping to encourage (the “top 25% of the most environmentally conscious builders” and all that). It is a good system and certainly worth rewarding but doesn’t really fit with the “mandatory minimum for green” in that it is more oriented towards optimizing comfort than saving energy, enhancing durability, or improving indoor air quality in the types of homes that would be reaching for LEED-h certification. It’s a comfort standard, not a green building standard.
The green home I'm building now won't pass LEED-H
We're building an aging-in-place home with a Hybrid Solar-Propane radiant floor heating & domestic hot water system with 15 SEER heat pump for AC and back-up heat that is better than 30% more efficient than code. The house scores gold in NAHB's Model Green Home Building Guidelines and North Carolina's Healthy Built Homes, but it will not qualify for basic LEED-h due to a "lack of comfort" in the AC design that will be used at most two months out of the year. If not for this requirement I think the house would likely be LEED-h Silver but I'm not going to pay to have the house scored when I know that it will fail because of this single requirement.
Seems like a missed opportunity to me.
NAHB is taking advantage of that opportunity
Last summer as we worked on the new NAHB-ICC National Green Building Standard the group discussed following LEED’s footsteps on this issue and decided that we shouldn't disqualify a house for a green rating because the bathrooms and bedrooms might occasionally be slightly less comfortable than the living room. So we awarded points for Manual D implementation but didn’t make it mandatory. The issue is to step lightly on the planet, not to assure that everybody is optimally comfortable at all times regardless of the additional cost.
--Michael Chandler is a home builder and master plumber in Mebane, North Carolina. His website is www.chandlerdesignbuild.com
Monday, June 16, 2008
I have nothing against water: I make coffee with it, paddle a canoe in it, and I even drink it every day. But it's not always what my empty hand is looking for when I settle down in the back yard and fire up the bar-b-que. Beer sort of hits the spot at these times. To determing whether I should be drinking cold beer in a can or cold beer in a bottle, I called my local recycling coordinator who wasted no time in telling me that tap water was my best choice.
Tap water wasn't what I was after, so I refined my query
Listening to NPR on the way home from work one day I heard that recycling 30 beer cans saved the equivalent of a gallon of gas. How many beer bottles, I wondered, would be equivalent to 30 beer cans. So I asked my local recycling coordinator He did some research and we ran the numbers. It turns out that 385 beer bottles has the equivalent embodied energy of 30 beer cans. He pointed out that there was some minimal adjustment needed to account for the transportation cost of imported beer so this calculation would be most accurate if applied to domestic beer in both bottles and cans. Ah-ha! I said, this gives me an environmental rationalization for buying that nice local microbrew!
Does this mean I get to "invest" in a kegerator?
Actually he replied, the kegorator idea is a no-go due to the carbon footprint of the refrigerator (regardless of the impact of the increased beer consumption). However, if you consider that there are 22 shots of bourbon in a bottle that likely has the embodied energy content of two beer bottles this gives you an environmental justification for drinking bourbon on the rocks (or mint juleps). If a single beer can equals 12.83 beer bottles it is roughly equivalent to six bottles of bourbon in terms of its carbon footprint.
As a dedicated environmentalist I find his logic irrefutable.
--Michael Chandler is a builder near Chapel Hill, North Carolina. His website is http://www.chandlerdesignbuild,com/
[Ed's note: for some fun recycling facts go to http://www.oberlin.edu/recycle/facts.html]
Friday, June 13, 2008
Thirty-five years and many variations of homebuilding, remodeling and carpentry jobs later, I’m still in the building business and consider myself extremely lucky to have found a profession I thoroughly enjoy and that has always provided me with a means to meet the needs of myself and my family.
I first learned about energy efficiency in the late seventies. I was working as an apprentice carpenter and I knew a guy who was starting a business using a new insulation material, polyurethane foam. We were doing retrofits on existing homes and my job was to drill a two inch hole every sixteen inches around the perimeter of the house. He would then fill the stud cavities with foam and I would plug the hole. This was after the oil embargo of the mid seventies when everyone suddenly became energy conscious. After awhile, oil and gas prices dropped and miraculously there was seemingly no more energy problem. I knew in the back of my mind that there was something to this tight construction idea and began employing what are now called “Green Building” techniques on all my projects whenever I could.
Almost twenty years later, again I had the good fortune to go to work for one of the pioneer production green builders in the country. The founders of McStain Neighborhoods had been employing sustainable building and development techniques before they were referred to as green building but always had the environment in mind. This is where I really got the opportunity to research and develop cutting edge building technologies related to highly sustainable, high performance home construction.. I have also realized that much of what those “old school” guys that I worked with all those years ago taught me about framing, flashing and details to make buildings last longer is now a part of what we refer to as Building Science.
Green building has become a passion for me and I am of the opinion that there is simply no other way to build. In order to construct environmentally responsible, healthy, long lasting structures, you must take a holistic, systems approach to design and building.
I live in a house that is almost one hundred years old and it is still a safe, comfortable place to live and promises to be for many years to come. We have the ability to create buildings that people will be saying that about several hundred years from now. That’s exciting to think about and we owe it to our grandkids.
--Jeff Medanich is Vice President of Harvard Communities in Denver, Colo
It's all in the details
That year we decided the only way to really understand home energy performance was to monitor their energy consumption. We tracked the monthly utility bills for every home we built from 1985 to 2000. Along the way, I learned as much as I could from as many sources as I could about energy and resource efficiency, all this long before the terms healthy or green building popped up. And I learned that the buzz words don’t mean that much, especially if they are not backed up by attention to detail. I can build a home of sticks, or SIPs, or ICFs and all three homes will perform about the same, so long as we are all paying attention to details during construction. Picking the strategies, systems, and technologies is the easy part; putting them all together on site in the right way is the hard part.
To me, green building is about “passing it on.”
I have spent a lot of time teaching both builders and high school students how to build well, sharing with anyone who will listen what I have learned about energy and resource efficiency over the years. I worked hard on the adoption of the International Residential Code (IRC) in Texas, when most said it could not be done. It won’t work if just some of us change the way we build; it is going to take all of us working together on this one.
--Jim Sargent is a green custom builder in Dallas, Texas
Friday, June 6, 2008
By Matt Golden
At Sustainable Spaces, when we work with homeowners to develop a roadmap for retrofitting their houses, we emphasize getting the basics, or the infrastructure, done right. It might not be sexy, but it is the core of the house. After looking at the basics, we focus on major systems, such as heating systems, water heating, ventilation, and air-conditioning. Once the house is operating efficiently, with good air quality and comfort, then we look at properly sized renewable energy systems such as solar and wind. These systems will be much smaller (and more affordable) because the house now uses much less energy.
But what can a homeowner do right now that will have an impact on their energy load, without involving a major home remodel? Here's my top five list of improvements anyone can make to get on the path of energy efficiency, at a reasonable cost.
1) Get a home energy audit - Start by evaluating your entire house as a system. It’s not about products; it’s about results. A building science-based audit will help you create a plan to fix your home based on what will have the maximum results. And PG&E will even help underwrite this audit! See EnergyStar.gov for more info
2) Reduce air leakage - Heated or air-conditioned air leaks out through gaps, cracks and holes in your home’s walls and ceilings and means your energy dollars are floating away. Sealing these penetrations is the most cost effective way to save energy. Most leaks are between your house and your attic. Read a Fine Homebuilding article on the topic here.
3) Seal your ducts - In California, the average duct systems (the tubes that move heat from your furnace to your house), has 30% leakage. When you figure that 40% to 50% of your home’s energy goes through this system, you can see that it has a huge impact on your bill. This system is also responsible for your home’s comfort and indoor air quality. Leaky ducts bring in dirty air from all the worse places to replace the air that escapes. Poor design and leaks mean that there is imbalanced distribution that results in cold and hot rooms, and general discomfort. When sealing duct work, use mastic not duct tape.
4) Add insulation - Adding insulation should happen after you air seal (or air sealing becomes very hard to do later). Generally adding insulation to the attic is the easiest and has the fastest return. You should have 10 inches of insulation or R-30+. We recommend using blow-in cellulose (recycled newspapers). If you want to do it yourself and use batts, try to get blue jean batts – but remember that you must install the insulation very carefully, as most insulation only performs at 50% of its rated value due to air gaps, compressions, and other installation defects. When adding a layer of batts to an attic, lay it perpendicular to the first layer to help reduce air gaps.
5) Replace light bulbs / appliances / plug-loads - Compact Florescent Bulbs (CFLs) use 25% the energy for the same amount of light. Replacing a 15 year old refrigerator with an energy star model can cut your bill by 60%. That's a pretty substantial amount in two steps. Plug loads can be negated with a power strip plugged into a switchable wall outlet.
Not everyone can make their home 100% green and zero energy in the ﬁrst-pass, but by creating a comprehensive plan homeowners can begin the path towards sustainability and see real results on almost any budget.
And remember, a green house does not necessarily mean it is full of fancy new technology. There’s usually 30% to 40% waste just in these fundamental issues that don’t need fancy solutions to resolve them!
--Matt Golden is president of Sustainable Spaces, a home energy performance company in San Francisco, Calif