Tag Archives: Chapter 15 – Creating a Connection

Building Fundamentals: Energy Efficiency Geekout – Anatomy of Windows and Doors Part I

This article by Clarke Snell was originally published in the New Life Journal.

If you ask 10 kids to draw a picture of a house, I can almost guarantee that they’ll all include a door and at least one big window. Ask those same kids 25 years later to describe their dream houses and I predict they will all be crammed full of windows. What I’m saying here is that in my experience, we all love windows. What’s wrong with that? Well, if our goal is to create an energy efficient building, typical glass-filled openings are actually a real pain in the astragal because compared to modern wall systems they perform horribly. In this month’s column, I’ll explain the basics of why this is true. Then next month, I’ll tell you what you can do about it.

Sidebar: R-value vs. U-value

Resistance to heat flow in building materials is usually quantified as R-value. The higher the R, the better the insulation. Just to confuse us, the insulation value of windows is expressed as U-value which is the inverse of R. To find out the R-value of a window, divide 1 by its U-value. For example, U= .4; 1÷.4 = R2.5

Heat Loss

Other than keeping rain and snow out of your bed, perhaps the most pivotal function of your house is its ability to create a different temperature inside than the temperature outside. This is accomplished by wrapping the interior space with insulation, a generic term for a material designed to resist the flow of heat. To oversimplify for our purposes, the better this insulation cocoon functions, the less heating or cooling the building will need. Since heating and cooling both cost money and usually involve global warming creating carbon emissions (our buildings are responsible for about 50% of our collective carbon footprint), improving insulation has been a focus of the green building movement. In recent years, we’ve made incredible strides and now have access to insulation systems that can produce walls systems with R-values (see sidebar) in the 20’s, 30’s, and even 40’s. Typical new windows, however, have R-values of only 2 or 3, 10 or more times worse than the wall itself. This is almost equivalent to a thermal hole in the wall. Therefore, the main performance flop for windows is their inadequate resistance to the flow of heat.

Mean Radiant Temperature

Mean radiant temperature is basically the average temperature of the surfaces of everything in the vicinity of your body. In a house, that means the surface of windows, walls, furniture, dusty knickknacks, and everything else. All of these surfaces radiate heat outward toward your skin, and your skin in turn radiates toward them. Since windows are so bad at slowing heat movement, their surface temperature will tend to be very different than that of other surfaces in your house. If the surface temperature of an object near you is considerably less or more than that of your body, you feel it as cold or warmth. This is why on a cold winter day, the thermostat can read 70F and you’ll still feel cold standing by a window. Low surface temperature, then, is another way windows drag down the overall thermal performance of our wall system.

Air Leakage

Doors and operable windows are basically huge holes that can be opened and closed. By definition, though, that closure is never perfect. The hole always leaks. Gaps and cracks in our wall will allow air to bypass insulation resulting in the movement of heat in or out of our building. Therefore, another strike against windows and doors is their contribution to this air leakage.

Solar Heat Gain

Responsible energy efficient designs incorporate a basically infinite, free source of energy: the sun. In our climate this means letting the sun in during the winter.  We need glass-filled openings to accomplish this. Different glass types and configurations let in more or less of the sunlight that hits them. This is quantified as a number called the solar heat gain coefficient (SHGC) which is basically the percentage of potential solar heat that glass lets into the building. For example, a SHCG of .5 means that 50% of the potential solar heat is making it through the glass. There are situations where we want solar heat gain and others where we don’t, so the wrong glass type in the wrong place can be a major detriment to building performance.


The point I’m making here is that windows and doors are typically VERY weak spots in the performance of a modern building. Next month, I’ll give you the skinny on how to choose the right windows and doors for new construction and remodeling or how to spiff up the performance of your existing underachieving glass units.

Building Fundamentals: Energy Efficiency Geekout – Anatomy of Windows and Doors Part 2

This article by Clarke Snell was first published in the New Life Journal.

Last month I ragged on windows and doors, pointing out that they are generally a very weak spot  in the performance of a modern, environmentally conscious building. To summarize: they don’t insulate very well, are a source of air leakage, can cause perceived discomfort, and can either let in too much solar heat when it’s not wanted or block too much solar heat when it is wanted. The obvious question is, “What can we do about it?”

Luckily, a lot of really smart people have been working on window technology in recent years and they are making big strides. If you are looking to build a new house, there are good choices to be made to improve the energy efficiency of your doors and windows. Similarly, if you want to increase the performance of your existing house, replacing windows and doors is a good place to start.

Sidebar: R-value vs. U-value

Resistance to heat flow in building materials is usually quantified as R-value. The higher the R, the better the insulation. Just to confuse us, the insulation value of windows is expressed as U-value which is the inverse of R. To find out the R-value of a window, divide 1 by its U-value. For example, U= .4; 1÷.4 = R-2.5

If you want to understand the mechanics, there’s a lot to learn. For example, most windows have two glass panes separated by a space filled with air or another gas, but triple pane windows with much lower U-values (see sidebar) are becoming more common. Then there’s the issue of low-e coatings, basically coatings that increase efficiency by reflecting heat energy. Windows can have different numbers and types of coatings configured to reflect heat in or out. Frame type is also important with choices ranging from metal to vinyl to wood to fiberglass. Glazing spacers, thermally broken frames, gas fills, closure mechanisms…the list goes on.

You really don’t need to worry about most of that stuff because all of this technology is synopsized in three quantifiable performance characteristics: U-value, solar heat gain coefficient, and air leakage rate. The National Fenestration Rating Council has created a standardized rating system that requires computer modeling and lab testing for verification of these variables. The results of these tests are prominently displayed on a label you’ll find on any new window or door. If it’s not labeled, don’t buy it. If you are talking with any professional, be sure to reference these numbers and make clear that you want values for the whole window or door unit, not just the glass. Armed with this basic knowledge, I can now offer you some simple rules of thumb summarized in the following chart:

Wind or Door Facing

U-value (BTU/hr-sf-F)


Air Leakage (CFM/sf)







East, West, North1














* My advice is for you not to go below these performance ratings

1East, west, and north facing openings. In terms of winter solar heat gain, these windows will be a net loss. No matter how much sunlight you can let in, the energy gained won’t be enough to offset the energy lost when the sun isn’t shining through the glass. Therefore, choose windows and doors with the lowest SHGC, U-value, and air leakage rates that you can afford.

2South facing openings. For glass that faces south AND gets full sun at least between 10:00am and 2:00pm all winter, choose windows and doors with the lowest U-value and air leakage but highest SHGC. NOTE: There is a new building code in effect setting a maximum SHGC for windows which is well below the desirable SHGC for south-facing windows that get full winter sun. There are ways around this glitch that are too involved to describe in this column. Just be sure to get this worked out with your builder and code officials before ordering windows.

As you start to shop for windows and doors, you may think that some of my chart numbers are wrong. According to NFRC specs, they aren’t. Right now, there are a huge range of performance levels and corresponding prices for windows and doors. Windows made in Europe, such as by the German manufacturer Optiwin, are the best, but they can cost more than $100/square foot. (Compare this to perhaps $15-20/sf for a decent off the shelf window in the US.) Canadian and US manufacturers are catching up in the performance category, so you just have to look around.

On the other hand, if you can’t afford the premium windows, there are other low-budget strategies. Covering glass openings with thick curtains anytime you aren’t in a room will increase window efficiency. If you live in an old drafty house, you can buy shrink wrap plastic to cover your single pane windows in the winter probably for less than $20. You’ll most likely immediately experience an increase in comfort due to higher radiant surface temperature (see last month’s column) and reduced air infiltration.

Regardless of the specifics of your situation, my point is simple. If you want to reduce your heating and cooling bills, improve interior comfort, and reach carbon reduction nirvana, don’t neglect your doors and windows.

A sample NFRC window label

Building Fundamentals: Engineering Fundamentals

This interview by Clarke Snell was originally published in the New Life Journal.

I moved to this region about 15 years ago because I thought it would be a better place to set up a homestead. I was looking for mountain spring water and milder temperatures than my Texas home. I found both, but the longer I’ve been here, the more I’m amazed by the people who live here, especially the ones I meet in my work in the world of “green building”. For my next few columns, I’m going to interview one of these local founts of wisdom on some aspect of all things green. This month, I talked with local mechanical engineer Jeff Buscher:

You and I are old enough to remember that ancient time before “green building” was a household word. How did you first get involved in the field?

I was studying architecture and engineering at Kansas State University when I read the book “Ecotopia” in an elective philosophy class. I remember it as a turning point for me. I started focusing on energy efficient technologies and sustainable practices in whatever way I could. After graduation, I worked for a large commercial engineering firm in Dallas for a number of years. It was frustrating because I kept pushing for sensible energy efficiency measures, putting them into designs only invariably to have them taken out at some point due to shortsighted reasoning, such as short-term construction cost reductions over long-term operating cost savings, let alone considering the additional environmental benefits. I finally decided to put my money where my mouth was and move to a smaller firm identified with green principles.

You and I have been working together for a while and I’ve come to really value your perspective. You’re unique in my experience because you combine an expansive knowledge of complex technology and technical methods with an interest in simple technologies, such as those commonly referred to as “natural building”. Given that novel perspective, what do you see as the important issues for “green building” enthusiasts to focus on?

First of all, we’ve got to face reality. The conventional construction world is in the grip of two dangerous forces: ignorance and inertia. Ignorance because efficiency has only been a concern for one generation.  We’re all still learning the best way to do this, but frankly, many building professionals aren’t educated as to even the most basic, common sense issues of building science. Inertia because to make money and avoid getting sued it makes sense to keep doing the thing that worked the last time. In other words, the construction industry is wary of innovation and slow to change. Real innovations tend to come from small companies that are light on their feet and driven through passion to do interesting things. Even in the “green building” industry most people are content to build to code. Forget codes. Building to code is the bare minimum acceptable to avoid being fined for breaking the law. To get where we need to be, we should be building at least two times in excess of current code mandated insulation levels. By achieving that level of performance we can significantly downsize or eliminate heating and cooling systems and make zero net energy buildings financially feasible. [Note: Zero Energy Design (ZED) can be defined as designing buildings that produce as much or more energy than they use.] ZED has been possible and achieved for decades. It’s not technically all that difficult to do.  It’s rare because it requires more design effort, and with current solar prices it costs a little more up front.  However,  the long-term benefits are huge. The question today is whether we can afford not to do it.

ZED is just barely starting to make it onto the mainstream radar. I think to a lot of people it sounds like something out of a science fiction novel. Can you shed a little light on the steps to move from conventional construction practices to ZED?

Well, it’s true that there is some high-tech involved, but many of the steps are old school. These concepts have been around for millennia.  First, we start with the land. Maximize what you can get from the building site and the surrounding area. Work with the sun for passive solar heating and cooling. Collect water on the site. Use as many materials from as close to the site as possible. Next, we need to stop building these light, expendable, giant boxes that pass for houses, office buildings, malls, what have you. We need more insulation and more mass. Insulation is a common concept for most people, but mass not so much. Adding heavy, dense materials (mass) adds to temperature stability and longevity of a building. This is a common approach in Europe, but we’ve missed the boat here.

In our climate, by creating a highly insulated building, you can drastically reduce the heating load, and by using a lot of mass you can potentially avoid mechanical cooling to keep the building comfortable. When compared to complex mechanical systems, insulation and mass are inexpensive and, once installed, they don’t require any additional input of energy to do their job. Past a certain threshold of load reduction, current “alternatives” such as solar electricity (PV), wind generators, solar hot water, and waste heat recovery start to become the sensible default solution rather than a luxury. This is where engineering becomes pivotal. Through energy modeling and integrating systems design with passive aspects of the building’s performance (insulation, mass, solar heating and cooling), we can create buildings that require only a fraction of the energy and resources to build and run compared to present common practice in this country.

The single variable that has the most effect on a building’s energy and resource efficiency is it’s size, so another major component of this strategy is to build smaller. Finally, we have to stop looking at our buildings as islands and start seeing them in their social context. A small, energy efficient eco-cottage is still missing the point if it’s part of a lifestyle that requires a two hour daily commute. Mixed use. Co-housing. Go local.  Live where you work.  Eat where you live. We should be designing to make driving less convenient and walking, and biking more convenient. I’m a big fan of the New Urbanism movement and recommend that people read up on it.

I’m with you on all of this, but one thing that makes me a bit nervous is our increasing dependence on complex technology. I’ve always been a do-it-yourselfer, but now I find myself spending more and more time in front of a computer whose inner workings are a complete mystery to me. That makes me fundamentally uneasy. What’s your take on the possibility of taking technology too far?

Obviously, that’s a danger. However, my personal feeling is that we need to find a way to solve our environmental problems while maintaining some level of the “comfort zone” that modern humans have become accustomed to. Technology can be a very useful tool in that context.  For example, in our climate, humidity is extreme. Around here, there is no way to create stable indoor humidity levels without some level of mechanical equipment. For me, the fun is in finding ways to limit and simplify the technology required to solve problems like this. I’m working on it, and I know others are too, so stay tuned.

To find out more about what Jeff thinks about, check out his blog at www.thinkorthwim.com and check out these sources of information that he recommends:

  • Walkable towns:  www.ecotownz.co.uk
  • Andrés Duany’s talk about how to avoid suburban sprawl:  www.youtube.com/watch?v=Ysoth-DYs78
  • ZED Architects in the UK:  www.zedfactory.com
  • Passive House Institute:  www.passivehouse.us
  • The Living Building Standard (No credits, just prerequisites.  It’s about what you did good, rather than being about what you did less bad.):  http://www.cascadiagbc.org/lbc

Footloose and Carbon Free: The Passive House Standard

This article by Clarke Snell was originally published in the New Life Journal.

Okay, by now everyone has gotten the “human induced global climate change” memo, right? If not, here’s the executive summary: We burn a lot of fuel for heating, cooling, manufacturing, generating electricity, and driving stuff around. That burning releases carbon dioxide (CO2). As CO2 levels increase, the atmosphere basically traps more solar heat, causing temperatures to rise. The dynamics of all this are pretty complicated and the details are debated, but there is a frighteningly solid majority of climate scientists who agree that we need to drastically reduce emissions of CO2 (and other “greenhouse gases”) if we are to avoid catastrophic climate change.

In the US, our buildings are responsible for about 50% of our carbon footprint. Therefore, if we take this somber warning seriously, we need to do a major overhaul of how we build…and fast. Luckily, since carbon emissions come from energy use, the solution is simply to use less energy, something that saves money, reduces pollution, and makes us more self-reliant. That’s right, it’s patriotic, baby!

The concept is really pretty simple. First, we greatly improve the efficiency of the building itself. We do that by reducing heating and cooling demand by increasing insulation levels and carefully sealing up air leaks. We then install a nifty device called an energy recovery ventilator which allows us to bring in fresh air with only minimum energy loss. Next, we focus on the sun, letting it in the winter for heat and blocking it in the summer for cooling. We also add  interior thermal mass to help store this energy. Finally we choose the most efficient systems, including mechanicals, appliances, lights, and anything else that uses energy.

If we do all of this right, we can reduce heating and cooling loads by 90% over the norm and cut electrical consumption by at least 70%. At this point, we’ve significantly reduced the carbon emissions associated with our building. However, to reach carbon reduction benchmarks based on climate science predictions (translation: to save the world as we know it, yeah!!) we need to go even further. We have to make all of the energy our building needs without releasing carbon, which basically means without burning fossil fuels (coal and petroleum). No big deal. Solar, wind, and hydro electric power are all available options. What’s more, our energy demand is so low now, these systems can be much smaller and therefore more affordable.

To go all the way, we need to make enough surplus renewable, non-carbon emitting energy to offset the carbon emissions produced to build the building, even to make the solar panels and other renewable systems we have installed. If we do all of this, we have reached carbon neutrality. In other words, our building is not involved in carbon emissions and is therefore doing its part to avert “human induced climate change” (see memo…you did get the memo didn’t you?) What’s more, the building will cost almost nothing to run and will have wonderful indoor air quality.

What’s the catch? Well, though the concept is simple, the application isn’t. First of all, when we get to this level of energy efficiency, some of our typical building components are woefully inadequate. For example, conventional windows and doors are just sieves for heat and air loss. Though high performance fenestration is available, it’s very expensive. In addition, the tiny air leakage allowable to make this work is simply outside the experience of US builders. Very careful attention to a variety of construction details is required, often using tapes and gaskets that are hard to find for sale in this country. There are other difficulties, all of which have to do with money. Though these buildings cost considerably less in a lifecycle analysis, the fact is that it simply costs more money upfront to save money, energy, and carbon emissions in the long wrong.

Luckily, if we want to move in the direction of carbon neutral construction, and I feel we have to, there are sensible, proven methodologies already in existence. The one I like the best is a certification program called Passive House. There are many thousands of buildings that have been built to this standard and performance monitored throughout Europe, mostly in Germany, though almost none to date in the US. The Passive House standard is laughably simple to grasp. You are allowed a given amount of heating and cooling energy per square foot of building as well as a defined rate of allowable air leakage. You then have to design a building envelope (basically insulation and air leakage strategy) and mechanical system that will perform at that level regardless of the climate in which you live. In other words, you can’t take a common “out” popular in the US green building movement: build a low efficiency building then attach a huge, expensive solar electric system that provides 25% of a large household energy demand and call it efficient.

The Passive House standard is administered in the US by the Passive House Institute US. These wonderful folks are hard at work training consultants, certifying buildings, helping to import or develop requisite materials, and educating the public. For more information, visit their web site at  www.passivehouse.us . If you want to see the process up close, we are hoping to build a Passive House certified building in West Asheville starting later this spring. To find out more, go to our project website at www.thenauhaus.com.

Building Fundamentals: Building "Green" Beyond the Home

This article by Clarke Snell was originally published in the New Life Journal.

If you think about it, the “green” in green building refers to plants. Our health and survival depends on the color green in the form of a vibrant plant committee with which we coexist. That’s why it’s surprising to me how often a “green building” project doesn’t include a focus on the area around the building, the place for interaction with plants and the rest of the natural world. This month I sat down with permaculture and edible landscaping expert Chuck Marsh to discuss how we can reconnect with the area around our houses.

I went to my first permaculture event, a design course in Texas, about 20 years ago. Since then, it seems that permaculture has gained almost mainstream status as a design system. Still, I don’t often see it defined. From your point of view, what is permaculture?

Permaculture is an ecological design system for the creation of regenerative human habitats. “Regenerative” is a key word here. Sustainability means “to hold up”, to maintain. I think we’ve reached a point where that’s not enough. We have a higher calling than to maintain what is. We now need to build up, to reweave the web of life, to restore abundance and diversity to the landscapes and spaces that we inhabit. So, while many people think that permaculture is a gardening system, it is in fact a complete ecological design approach to craft how humans inhabit landscapes whether built, planted, or natural.

As I look at houses, whether they’re in the city or the country, new construction or older in a historic neighborhood, I’m struck by how little the area around the building is actually used. Few people grow food anymore or craft outdoor space that allows them to spend productive time outside. Can permaculture help us connect again with the world outside our front doors?

Everything we build, plant, or just leave alone is an element of our landscape. A central goal of permaculture is to foster relationships so that the yields of one element meet the needs of another. We want to create interdependence.

The house, then, is one piece of a whole system. It has all kinds of companions. Driveways, pathways, gardens, existing habitats, outbuildings, etc. Let’s take a central tenet of green building: energy efficiency. If we consider only the house, we’ll add insulation and energy efficient appliances, then consider the job done. But if we see the house in relationship to the landscape, we can find many more opportunities to conserve. For example, we can place trees for cooling, either through redirecting wind, establishing natural vortexes of air movement, or creating shade. We can also introduce plantings to block winter winds, therefore preventing heat loss in the building.

These same plants can provide food and be a natural habitat, in other words they are multifunctional and therefore can be part of a complex interplay between elements. This multi-functionality is also central to permaculture. So, for example, in addition to being a lane of passage, pavement or pathway surfaces can be chosen to add heating or cooling to the area around a house. In combination with plantings, they can provide both. A bird bath or garden pool can be placed at the right angle in the right spot to bring light and passive solar energy into the house while adding color variation and the magic visual combination of light reflected from water. These are just examples of ways that multifunctional landscape elements can work together to simultaneously create food, thermal efficiency, natural habitat, visual beauty and many other positive effects on the livability of both the interior and exterior environment.

Of course, we used to do this. Nobody had lawns until the beginning of the 20th Century. Instead, people had what were called “door yards”. This was an outdoor space whose center was the kitchen door. It was swept, not vegetated, and was the space where clothes were washed, meals cooked, and beans shucked. Chickens were kept here and fed recycled food scraps in exchange for eggs. Today’s patios are a poor representation, a non-functional replica, of these yards. I think there’s a desire to move back in the direction of useable outdoor space. You see it in high-end outdoor kitchens being included in large custom homes. We can do the same thing and much more at the lower end of the budget scale too.

What can people do to start the process toward reengaging with the area around their houses?

The first step is to throw out the idea of a “maintenance free yard”. Maintenance has gotten a bad rap, but essentially it means “to care for”. Maintenance is love. We need to be creating landscapes that draw us outside, that pull us into interaction. We need to lure kids away from computer generated magical landscapes to the real magic of the sights, smells, sounds, feelings, and tastes of the changing seasons.

How can we trigger this reengagement? The best way is through our mouths. That’s how we discovered the world as toddlers. Therefore, we start with edible plants. We place them along paths and in front of doors, places where people will naturally pass by and take a taste. Next, we intermingle plants and other elements that have different colors, different textures. We create an environment that engages all the senses as it changes through the seasons.

Fundamentally, I see the house as a place for refuge, safety, and nurturing, not for all human activities.  We are fortunate to live in a climate in which we can live comfortably outside for seven months of the year. By seeing the house as a single element of a larger landscape, we can shift many activities outside. Why, for example, heat up the indoors in the summer by cooking when an outdoor kitchen is both more enjoyable and comfortable during those months? Remember, too, that useable outdoor spaces are much cheaper to build than their interior counterparts.

The bottom line is that we need to transform our conception of outdoor environments from eye candy viewed through picture windows to functional spaces in symbiotic relationship with interior spaces. The result will be more efficient buildings, a more enjoyable lifestyle, and a reconnection with our true home, the earth.

Sidebar: Tips from Chuck

  1. Don’t place your house on your favorite spot. Doing so turns the sacred into the vulgar or common.
  2. Place your house consciously in the microclimate. For example, when building on a hill, site the building mid-slope. Ridge tops are windy and cold and basins are frost pockets.
  3. Avoid north, northwest exposure. Winter winds create convective heat loss in buildings. If there is no existing natural barrier, place outbuildings or windbreaks to block these winds.
  4. Start at your kitchen door and work outward. Gardens needing the most care should be near the kitchen. Once you’ve managed these, move outward.
  5. Make enjoyment easy. Place berry bushes and small fruited plants along paths and driveways so that you’ll pass by and graze.

CHUCK MARSH is a permaculture and edible landscaping/ecological land use teacher, designer, and consultant.  He is the founder of Useful Plants Nursery and a co-founder of Earthaven Ecovillage, south of Black Mountain, NC, where he lives and grows.  He can be contacted by phone at 828.669.1759 or by email at marsh2246@bellsouth.net.

Outdoor Rooms: Save the World With a Smile on Your Face

This article by Clarke Snell was originally published in the New Life Journal.

Given a choice, most of us would rather be outside. I mean, most people imagine vacations on the beach or walking through the woods, not sitting in a room with a TV on, an air conditioner humming, and the shades drawn. That’s not surprising because if you get down to basics, our home is the earth. Sure, you live in a house, but everything inside originated outside. Air, water, food, fuel, fabrics, even all of that plastic crap and junk mail. Origin: outside.

In fact, the whole concept of a place called “inside” is really an abstraction. We are a part of the outdoors, of the self-sustaining ecosystem of the earth, and as such we need a constant and intimate connection to the outside in order to survive and flourish. The only question is how we go about making that connection. The trend over the last 50 years or so has been to focus on creating indoor environments that can dial in specific variables (air temperature, water temperature, light intensities, etc.) with fine levels of control. A building with a mechanical heating and cooling system and electric lights, for example, can theoretically create a consistent indoor environment regardless of what is going on outside. That can be a good thing. However, if applied mindlessly, this paradigm leads to exorbitant energy consumption with its consequent pollution and pillaging of finite natural resources. (Since about 40% of the energy we use as a country is consumed by our buildings, that’s quite a bit of pillaging.) This approach also sets the stage for the cubicle, bad air fresheners masking poor indoor air quality, the video-game/TV-addict-couch-potato-geek and a variety of other side effects of extreme separation from the outdoors.

Don’t get me wrong. I’m not suggesting a return to the cave. Campfires are an extremely inefficient and polluting technology. A couple billion of them would be an environmental nightmare. All I’m proffering is that we expand the concept of where it is that we live. For example, we need to stop thinking of our houses as ending at the front door. For me, a house has three basic parts: indoor rooms, outdoor rooms, and the transitions between them. Outdoor rooms can be designed to be just as functional as indoor rooms. In fact, generally they mirror the uses of indoor rooms, allowing us to choose the best locale for a particular activity based on the weather. This layout can take a load off interior space while adding inexpensive outdoor space.

For example, a home office that combines an interior room with a private covered patio can allow the indoor portion to be much smaller. The same is true of kitchens, bedrooms, living rooms, even bathrooms in the right situation. The end result can be a smaller house with lower upfront cost, lower utility bills, and happier inhabitants who are spending more time outdoors while still going about their busy modern lives. Smaller buildings using less electricity and fuels also mean less pollution, fewer greenhouse gas emissions, and less dependence on foreign oil. As for existing buildings, adding outdoor rooms won’t make them smaller, but they’ll still benefit from considerably lower utility bills…you don’t need to heat or cool a building or run lighting when you’re outside.

Some of the hardships you might have to endure to reach these frugal and lofty goals are (1) sleeping outside under a ceiling fan on a screened porch off your bedroom; (2) cooking outdoors (five feet from your herb and greens garden) whenever you feel like it rather than waiting for that elusive “cookout”; (3) taking a private solar shower outdoors under an open sky (note to reader: don’t die without experiencing this!); and (4) typing those emails with the smell of flowers as a backdrop… It’s a hard job, but I say someone has to do it and it might as well be you.

Though many of us have experienced outdoor spaces that have elements of what I’m describing, most don’t. The reason usually is that they are being short-changed. Successful indoor rooms share basic components. They all have a floor, walls, and a roof, for example. They also all have a clear intended use that has been served through thoughtful design and careful follow-through in construction. Outdoor rooms are no different. The floor could be stones, the walls may include a bush, and the roof may prominently feature the sky, but the idea is the same: a collection of elements brought together to create a mood and support an activity. Outdoor rooms can be private, grandiose, playful, or solemn. They can be designed to maximize work productivity, encourage social interaction, or be a room of one’s own. In short, they can do anything an indoor room can do…just not in a blizzard.

Okay, so here’s my radical suggestion. Let’s enjoy ourselves immensely by spending more time outside; slash construction, maintenance and energy bills while doing it; AND cut pollution, carbon emissions, and consequently “save the world” in the bargain. All that’s standing in our way is the powerful aerosol air freshener lobby and some crazed X-Box geeks. Fight the power!

Next month: floors for outdoor rooms.

Is Wood Good? A Look at Burning Wood for Heat

This article by Clarke Snell originally appeared in the New Life Journal.

It’s winter, so I’m thinking a lot about wood. That’s because it’s a major strand in my life-line this time of year. I’m lucky enough to live in a house that is heated by a combination of direct sunlight and wood collected basically from my back yard. In a world that I am increasingly unable to grasp, it’s always a centering, empowering experience to warm myself with wood that I’ve cut, split, and hauled with my own hands.

A sensible question, though, is whether it’s environmentally responsible to burn wood for heat. The preamble to an answer to this question is that the “green” approach to heating has to start with a very well-insulated, weatherized building that maximizes the heating potential of the sun through passive and active solar design (see last month’s column for more info). These strategies will greatly reduce the amount of extra heat we’ll need in the building.

With that said, there are two basic environmental issues to consider: management of natural resources and pollution. As a resource, wood is both locally available and renewable. When you compare fighting wars over dwindling oil reserves to taking a chainsaw into your back yard, wood seems the clear winner. To my mind, IF (and this is a big IF) the wood is harvested in a sustainable fashion, then burning wood is a smart choice from the point of view of natural resource management.

That leaves the question of pollution. Is wood a clean burning fuel? The answer depends on how you burn it. To understand what I mean, we need a quick science lesson. (Full disclosure: I am not a combustion scientist, nor have I played one on TV.)

Combustion or “burning” is the chemical reaction between a heated substance (fuel) and oxygen. In the case of wood, there are three stages of combustion. In the first stage, wood heats up to the point that interior moisture turns to steam. This process actually consumes heat, so we are no closer to warming our feet at this point. With the water gone, though, the wood can get hotter and begins to vaporize releasing gases, better known as “smoke” to us laypeople. If the temperature is hot enough, this smoke will burn releasing heat in the process. After the gases have been released, what’s left is called “char” which is basically a pile of almost pure carbon. In the presence of enough heat and oxygen this carbon will combine with oxygen to produce carbon dioxide and release more heat.

Carbon dioxide?! Isn’t that a greenhouse gas that contributes to global warming? Yes, it is. The fact is that all types of combustion (whether coal, oil, gas, etc.) produce carbon dioxide. However, there is a difference. Trees take in carbon dioxide as they grow. When they die, fall, and decompose in the forest, they expel this carbon dioxide. If you burn wood, that same carbon dioxide is released, so theoretically there’s no global warming difference between letting wood decay and burning it. (The reality is, as usual, a bit more complicated, but, hey, remember I’m no combustion scientist.) On the other hand, the CO2 released from burning petroleum is CO2 that plants took in millions of years ago and has been sequestered all that time in the ground. Therefore, burning petroleum brings additional CO2 into the picture, and consequently contributes to human induced global warming.

If we accept this carbon dioxide argument, then how clean wood burns and how much of it’s potential energy is converted to heat is simply a function of how completely it combusts. If smoke is allowed to float away without combusting, the result is creosote and a bunch of nasty particulates that can pollute indoor and outdoor air. If the “char” doesn’t completely combust, the result is unburnt char and by-product carbon monoxide which as we all know is a poisonous gas. To avoid these environmental pitfalls, we need to (1) create enough heat and (2) contain the fuel.

Wet wood is the enemy of creating heat. A lot of energy is wasted burning off water which keeps temperatures low and therefore allows smoke to escape without burning.  The first step, then, regardless of stove type is to use well seasoned (dry) wood. Next, we need enough oxygen. Campfires burn well because they have access to plenty of oxygen. The problem is that the fire is on the bottom while vaporizing gases quickly rise away from the flames, therefore a lot of fuel just floats away unburned. We need to contain those gases in a heated environment so that they ignite after they rise away from the flames. Next, after the gases have burnt off, we need to keep burning the char hot enough to make sure minimal carbon monoxide is created. Finally, we have to find a way to store most of the heat off of this now incredibly hot, efficiently burning fire. If not we’ll quickly overheat our house.

Since we are geniuses, humans have created stove designs that solve these problems. In my opinion, the best of these are generically called “masonry wood heaters”. Though there are a number of variations, the basic idea is to burn wood hot and fast in a stove made of dense masonry materials (brick and stone) that then can absorb the heat and slowly release it into the house over many hours.

My favorite design is the “contraflow heater”. In this stove, wood is stacked log cabin style in a tall firebox made of firebrick with ample air intake basically creating an enclosed campfire. As smoke rises off the fire, it is confined and therefore compressed in a secondary combustion chamber where it ignites. Hot air from this combustion leaves the chamber at both ends and then travels back down the sides of the stove in channels created by another layer of brick that surrounds the stove. The air then enters the bottom of the chimney and moves out of the house. The brick soaks up much of the heat from the air as it travels up and then back down through the stove. Meanwhile back in the firebox, the char continues to combust in an environment of ample air and heat. After a couple of hours when combustion is complete, the stove damper and air intake is closed to prevent air movement out the chimney and the stove then slowly radiates its stored heat into the house for up to 24 hours. The result is an extremely efficient burn with very low particulates and a comfortable, even radiant heat.

As with all things, there are downsides. For one, masonry heaters are expensive and heavy, requiring a solid foundation to sit on. They also require a lifestyle adjustment over conventional heating sources. They heat up slowly, so you have to plan ahead if the stove has cooled down. In other words, no cranking up the thermostat when you get home from work.

Luckily, other wood stove technologies approximate the advantages of a masonry heater. New metal stoves have advanced catalytic combusters and/or ingenious air intake and injection strategies. Some metal stoves incorporate soapstone or other mass to allow for some amount of heat storage.

On the other hand, as I said earlier, there’s a bad way to burn wood. Metal stoves that are two large for the space or poorly designed require that you starve the fire to prevent overheating. Smoldering a log in an old damped down cast iron stove creates massive amounts of particulates and only turns about 25% of the wood into useful heat compared to 75% or more for a masonry stove. A roaring fire in an old-school fireplace is even worse, turning an estimated 0% (yes, you read that right) to 15% of the wood fuel into useful heat. If you’ve got an old metal stove, either modify it to include an air to air heat exchanger (here’s a link to show you how: http://www.aprovecho.org/), or get rid of it. Sell it for scrap or use it for yard art, but don’t pass it on to another user. If you are buying a metal wood stove, make sure that it is EPA approved (labeled EPA II).

To learn more about masonry wood stoves, check out the Masonry Heaters Association of North America. Their website is http://mha-net.org/html/library.htm. To further research metal wood stoves, first peruse this government website (http://www.epa.gov/woodstoves/index.html) so that you can impress your local wood stove dealer with some intelligent questions.

Building Fundamentals: Renewable Energy, a Discussion with Ole Sorensen

This article by Clarke Snell was originally printed in the New Life Journal.

When we meet with clients in our office for the first time to discuss their desires for a “green” house design, they seldom talk about pivotal but boring things like insulation levels or conscientious weatherization detailing. In fact they very often know very little about what might make the house itself “green”.  Invariably, though, they do discuss alternatives to conventional energy production. Solar electricity, hydronic in-floor heating, and solar hot water are almost always mentioned. That’s a good thing because our buildings are responsible for the lion’s share of our societal energy use and consequently play a huge role in our present pollution and environmental degradation problems. To help us all get a bead on our energy use options,  I sat down recently with Ole Sorensen of Solar Dynamics, a renewable energy system design and installation company based in Asheville.

Most of our clients say they want to take advantage of alternative energy technologies, but in my experience few know what that really means. What is “alternative energy”?

I try to stay away from the word “alternative”. To me “alternative energy” is coal and propane. In the final analysis, the only energy sources that make sense, the ones that need to be our primary sources, are those that can be part of a sustainable lifestyle. My ultimate goal is sustainability. A sustainable energy source is one that can be continually renewed. In other words, things that we don’t have to worry about running out of. As it turns out, almost all renewable energy on this planet comes from the sun. Every ½ hour enough energy from the sun hits the earth’s surface to power human civilization for a year. In other words, we don’t even need to be efficient, we just need to commit to tapping this basically infinite resource in it’s various forms.

The most basic solar energy is direct sunlight which can be used to heat buildings through passive solar design. Direct sunlight can also be used to heat water or some other liquid to create domestic hot water and energy for in-floor hydronic heating. We can also turn that same sunlight into electricity using photovoltaics. Wind-power and hydro-power are also forms of electricity whose power source is the sun. The sun heats air to, in combination with the rotation of the earth, create wind. The sun also evaporates water to create rain and other precipitation, the force that creates a constant cycle of falling water on the planet. We use both wind and falling water to turn turbines that create electricity. The energy held within ocean waves is another largely untapped source of solar energy that is starting to be commercialized for electricity production.

There is constant and exciting innovation in the world of renewable energy technology. However the tech stuff is only half of the equation to creating a sustainable approach to energy. The other part is lifestyle adjustment. Billy Jonas has an environmental song that my kids and I love that repeats the line, “It all comes from the groun-duh.” It’s a basic and profound point. All we have is this one earth. Duh. We simply have to find a balance between what we take and what we leave behind. I’ve seen statistics claiming that if everyone lived like we do in the US, we’d need five planets. Talk about unsustainable!

This is a point that really scares me. I know that we in the US are out of control in terms of our energy consumption and then it seems like the rest of the world is frantically trying to catch up with us. There just isn’t enough planet to go around. How do you see us getting out of this mess?

To illustrate let me tell you a story from my own life. I’m from Denmark and started out in a highly academic environment. I then decided to move into boat building. I couldn’t get my fellow classmates to approach the process academically. We had a hard time communicating. My teacher pointed out to me that my classmates and I were talking two different languages and asked me the question, “Who would have the easier time changing their language, you or them?” I realized that it was up to me to bridge the gap because my background gave me the skills.

I see our present energy and environmental problems in the same way. The rich industrialized countries are the ones using the most energy and creating the most pollution. We’re also the ones with the technology and resources to find sustainable solutions. It’s up to us to solve this problem, to change our language so to speak. Rather than having poorer countries struggling to catch up to us in our present consumption patterns, which is simply impossible, we can show the way for them to utilize renewable energy to prosper sustainably. The concept is not that hard to grasp. We are the ones who have the knowledge and are using the excess. It’s up to us to create enough for others. The wonderful thing is that we actually have the know-how to make this happen if we have the will.

As someone who has lived in this country almost all my life, that’s a little hard to imagine. Our whole paradigm is based on trying to get ahead, seemingly at any cost. How do we go about changing the paradigm. How do we go from being the problem to solving it?

We are already in the middle of the paradigm shift. It’s you and I and all our fellow citizens who create change and most people today want sustainable energy. There is a demand for it. The problem is that in many cases the solutions are not available to everyone because they are too expensive. Since I got into this business, PV (solar electric) panels have gone from 12 to 20% efficiency. In other words, panels now transform into electricity 20% of the solar energy that hits them. That’s an amazing technological improvement in a short time, but clearly there is a lot more energy there for us to capture. We simply need more research and development money to reap even greater improvements in efficiency that will allow prices to come down even further. If we really got behind renewables, put our money where our mouth is so to speak, we could be getting a lot more and paying a lot less.

Another problem is one of scale. As with most things, the smaller the system, the more you pay per unit. PV is just too expensive for most people to put on their houses right now, that’s why most PV installations are commercial. It’s the same with wind power. Commercial wind companies won’t even consider a project unless it’s in the 10 to 20 million dollar range. Smaller and the economics just don’t add up. I think we need more options than simply residential and large commercial. We need community and neighborhood renewable power plants, large enough so that they are affordable but not so large that we necessarily have to wait for the large power companies to get on board.

Countries with high percentages of renewable energy, Denmark for example produces about 20% of its electricity demand from wind, are doing things like this. They have some residential and apartment buildings, but also a lot of larger commercial projects. Germany has a single PV array covering the equivalent of 11 soccer fields. Another array stretches more than ½ mile along the highway to the Munich airport. Germany made a very conscious decision in the 1990’s to go solar. To put it simply, people there were willing to pay more to move toward sustainability and that created the political will to get the government involved. That’s what we need in this county. We need to step up to the plate in support of renewables and then hold our government accountable to make a meaningful transition to renewable energy.

Okay, so far you’ve been talking about the big picture which is of course very important, but it can also be a formula for inaction because we tend to feel overwhelmed with the scale of the problem. It seems that thinking globally and acting locally really fits in this context. You started your business to be part of the solution and your solution is making renewable energy available to residential customers. How does someone go about making renewable energy a part of their daily life, in other words a part of their present or planned house?

When someone comes to me, the first thing we do is discuss their dream. Every situation is unique and depends on a client’s energy consumption, square footage, sun or wind exposure, budget, and current tax credits. Honestly, people almost always begin with dreams of a lot of technology, then we start talking price and many people back off. We then look in their budget for the thing that will make the biggest difference. I like to look at it in terms of a “sustainability budget”. You budget for other things, why not sustainability. Let’s say you have $15,000 in your sustainability budget. In other words, you want to invest $15,000 now in moving toward energy sustainability. You’ll get this money back in utility bill savings over time, but it’s an upfront expenditure. What’s the best way to spend that money?

Well, energy production isn’t the first thing to consider. That’s my dilemma as a renewable energy installer. I need to keep in business, but I also have a responsibility to the planet and society. So when someone comes to me with limited funds, I tell them first to reduce their energy needs by building smaller and by creating an efficient building envelope, in other words installing more insulation and paying attention to weatherization. Next, I tell them to choose construction methods that will create a long-lasting durable building that won’t require a lot  of maintenance. Then we talk about reducing energy usage because the less energy you use, the more affordable your renewable energy system will be.

At this point we’re ready to talk about energy. Let’s go back to the original example of a modest $15,000 sustainability budget. My suggestion would be to spend $8,000 for additional insulation and $7,000 for a quality solar hot water system. You’ll get more bang for your buck this way than spending the $15,000 on a solar electric system. Don’t get me wrong. I applaud and support clients who make a commitment to PV. I’m just realistic that for the majority of people right now there are more cost effective ways to get the same positive environmental effects. If a client can’t afford PV, then my “best of both worlds” solution here is to install solar hot water and plan for an eventual PV system by putting in conduit and other inexpensive infrastructure as part of the initial construction process. If the budget just really can’t support even solar hot water, we can also install transmission lines in the wall and take other steps to make the eventual installation easy, efficient, and more cost effective. In my opinion, a solar hot water rough-in should be as important as a front door in new construction.

What about hydronic in-floor heating. Why do you install these systems?

Hydronic heating can use either radiators or can be set in a slab or under a floor. These systems, especially the in-floor variety, are sustainable because they are incredibly efficient. The boilers I use are 97% efficient and don’t require energy hog fans as with air source systems. In addition, hydronics can easily utilize direct solar radiation as a heat input. The same solar hot water heating system we’ve been discussing can do double duty as a heat source for your radiant heating system. In my opinion, hydronic heating has the lowest environmental impact of any heating system available, including burning wood. Of course, a big selling point for hydronics is comfort. In-floor hydronic heat creates a wonderful, mellow heat that doesn’t dry the air or make noise while it’s running.

One of the common complaints I hear about renewable energy systems is that the exposed machinery is “ugly”. What’s your response to that criticism?

Personally, I can get ruthless when it comes to aesthetics. If the most efficient car in the world looked like a piece of cheese, I’d drive a piece of cheese. Of course, as a company we are sensitive to and try to accommodate the aesthetic needs of our clients. To give solar panels as an example, at our latitude and with most roof pitches, it is going to be more efficient to raise roof-mounted panels at an angle to the roof. However, sometimes customers want their panels to lie flat on the roof because they feel it looks better. If our analysis tells us that this will result in only an insignificant reduction in system efficiency, we’re happy to do it. If, on the other hand, that isn’t the case, then we feel the need to stand our ground and install the panels at an angle to the roof. In the end, this always results in a much happier customer. We have to hold on to the big picture: our goal of sustainability. If it means getting over a perception of what you consider to be ugly, then so be it.

Here’s another example. One of our wind power customers had a hard time convincing his neighbors and the press that the wind turbine he planned to install wouldn’t be an eye sore. It wasn’t until we finished the installation that they realized what a simple, eloquent machine this was and not as huge as they imagined in their minds. One journalist even apologized and wrote a second positive article about it. Education is the key. When people complain about how ridge-top wind-power systems will adversely effect their “view shed”, I tell them that there won’t be a view shed without wind-power. In the last few years, there has been a marked deterioration in air quality even in our rural area. That’s not haze, people, that’s smog.

I like to say that sustainability and denial are archenemies. They just can’t work together. We have to decide to let go of our denial and embrace sustainability. To contact Ole and for more information on Solar Dynamics:

Phone: 828-665-8507 or 828-231-9106

Email: ole@solardynamicsnc.com

Web: http://solardynamicsnc.com

EcoDrain Wastewater Heat Exchanger

We have received City approval to install vertical GFX heat exchangers like the Power-pipe. They will recover 50% of the heat in the hot water used for a shower. The only problem is that they are 5 or 6 feet tall (there are shorter ones but they aren’t very efficient), and they have to be installed vertically. That means we can’t recover heat from a shower located on grade without pumping the drain water.

Today, my horizontal wastewater heat exchanger prayers seem to have been answered. EcoDrain claims their 30″ long horizontal heat exchanger will recover up to 40% of the energy in a shower. My first thought was “well, that’s going to clog immediately,” but EcoDrain thinks I should relax:

The contact area of the horizontal EcoDrain drain is coated with a very slippery environmentally friendly non-stick coating. This prevents anything from sticking to the device and makes it self cleaning. For further assurance, it is possible to purchase a hair cover for the drain which dramatically reduces the amount of hair that ends up in the drain.

A 4″ diameter vertical GFX heat exchanger can be installed on the main gray water drain leaving a house to recover heat from all showers, the washing machine, and dishwasher, but the EcoDrain is sized for a single shower at a time:

A single EcoDrain can be used for multiple showers provided the showers are rarely used simultaneously. There is a limit to the maximum flow on the supply side and also an optimal flow on the drain side. If multiple showers drain at the same time, there will be diminishing returns in terms of savings because the heat exchanger capacity may be exceeded resulting in some water just passing through the heat exchanger without transferring any heat.

That’s fine with me. Our clients should be washing clothes with cold water anyway, and the dishwasher doesn’t use a lot of hot water. The clothes washer and dishwasher are also non-coincident loads. They fill with hot water. They do their thing, and they drain later. You wouldn’t be recovering heat unless you happened to be running some water while one of them was draining. Showers are what we need to recover every time. The other fixtures are good to pick up if it’s not any trouble.

The horizontal EcoDrain fits in a box 30” long by 6” high by 2” wide. It is designed to fit between a p-trap and a main drain line under the floor of the shower.

The vertical EcoDrain is a tube of diameter 3” and length 30”.

Pressure drop is about 5 psi.

The larger GFX heat exchangers are probably the way to go if we have a basement because they’re more efficient, but EcoDrain will come in handy when we have a shower located in the basement.


:: Inhabitat

How Fiberglass Window Frames Are Made

The best windows in Europe are made with thermally broken wood frames, but the best windows in North America have fiberglass frames. The European wood windows have my vote for the best made windows in the world. I consider them art. However, I have to admit that fiberglass is a pretty ideal material for window frames.

As wood takes on water and dries it can warp. If it takes on enough water it can rot. Fiberglass, on the other hand is impervious.

Expansion and contraction are another problem. Aluminum frames expand about 3 times as much as glass when they are heated and vinyl expands 7 times as much as glass. Wood does not expand when heated. It expands with humidity. The varying expansion rates can result in stressed frames, broken seals, and inoperable hardware, but fiberglass frames have nearly the same coefficient of expansion that plate glass does.

Fiberglass frames are made by a process called pultrusion, a combination of the words ‘pull’ and ‘extrusion’. Vinyl and aluminum frames are extruded, meaning the material is melted and forced thru a die. With pultrusion, continuous glass fibers are pulled thru a resin impregnation bath and then a heated die where the resin sets into the desired shape. Here’s a pultrusion machine in action: