Architecture Classes Farmington NM
Houses That Really Work
Thirty years ago I was teaching physics at Bowdoin College in Brunswick, Maine, and living in an old farmhouse. In winter, the best that could be said of my 1809 farmhouse's uninsulated walls was that they slowed the wind to a moderate breeze. Many were the nights my wife and I couldn't keep a candle lit and took to our bed for survival. Some sympathetic soul lent me a copy of Rex Roberts' Your Engineered House. In it, Roberts, an MIT-trained engineer, dissected the structures we call home into their major components and subjected each to two questions:
1. What do we expect (or need) this thing to do?
2. How would one engineer the thing to best accomplish these goals?
What emerged under the harsh light of Roberts' socio/engineering analysis was disconcerting. Rather than reflecting and satisfying the needs of its occupants, the modern American home was seen to be little more than a Hollywood set, a "house beautiful" with little or no thought to function. I couldn't put the book down. My poor wife recalls my waking her at 1, 2, 3 and 4 a.m. with resounding whoops and poundings of the mattress as I encountered each new revelation. Just as some souls experience religious revelations and go forth to spread the word, I suddenly felt compelled to use my training in physics to make sense of shelter rather than subatomic particles. I created a course at Bowdoin in which the home became a multifaceted physics problem. We examined it with applications of the principles of heat, light, electricity, magnetism and mechanics. The students loved it, but the other faculty members hated it. From their ivory towers, many viewed the course as something more appropriate for a vocational school.
The course was simply too practical for the elite future leaders of the world. But the sympathetic dean wisely suggested I retitle the course "The Art of the House." Under that guise, I taught "hammer and nails" (as the students fondly called it) three times. At the same time, John N. Cole was writing a weekly column in the Maine Times describing the design and construction of his family home. I loved the humanity of the process - the natural activity of building of one's own nest, as Thoreau so eloquently penned. We met for lunch. Cole told me of his frustration in dealing with issues such as site selection, orientation, building codes, digging a well, designing rafters that would support the Maine snow load, acoustic privacy, insulation levels and on and on. I told John about my course. From that three-hour lunch came the idea for Shelter Institute, the nation's first owner-builder school, and the promise to try to write a book based on my course. One minor point: I couldn't write. At least, that had been the opinion of every one of my high school and college English teachers, as well as my MIT thesis committee. Undeterred, John took me in tow to his editor at the Atlantic Monthly Press. The editor, penny loafers propped on manuscript-encumbered desk and pipe tucked in the jacket of his tweed jacket, raised the same issue. "How do I know Wing here can write?" was his simple - and to my mind logical - question. "Oh, anyone can write," Cole said. "In fact, I'm so sure this guy can write that if he can't, I'll do it for him." John was right, anyone can write - as long as they have something to say. I had a lot I wanted to tell the world and so did John. So we co-authored From the Ground Up. I described the physics and John composed the poetry of creating shelter. That was 30 years ago. The words we wrote back then were philosophical and practical truths and, as such, have not changed.
What's changed are the technologies and materials that make the process easier than ever. I feel, more than ever, compelled to spread the word - in John's words, to "provide readers with what they need to know to plan, design, site and build their own shelter for themselves and their family; a sturdy structure that conserves energy, saves money, enhances comfort and allows all who live within it the opportunity to exist in greater harmony with the natural world." This is the first chapter of the new From the Ground Up. I hope it causes at least a few of our readers to pound their mattresses at 3 a.m. Architects have a saying with which I totally agree: "You can't build a good house on a bad site." I would add, as a corollary, that it is difficult to build a truly bad house on a good site. I am sure you also have heard the old real estate saw: What are the three most important factors in real estate? Location, location, location. In other words, the single most important element in the design and construction of a home is its site. By "site" most people mean proximity to shopping, quality of schools, tax rate, crime rate, population density and commuting distance - the factors that make some areas more popular and more expensive than others. Equally important, however, are the factors that dictate how your house should be built and situated. Together, these factors are called "climate." If you have traveled in the United States, you have probably noticed that homes in New England are very different from homes in Florida.
The typical home in New England is a compact Cape (Cape Cod style) with a center chimney and fireplace, full basement and low ceilings. The typical home in Florida is all masonry and stucco with high ceilings and no basement at all. These regional differences in architecture have evolved, largely without input from architects or energy experts, in response to climate. Here's how it works: someone builds a house just a bit different from the norm. If that difference turns out to make the house more comfortable, then it tends to be copied. If, on the other hand, the difference makes the house less comfortable, then it's less likely to be copied. So houses, like animals, naturally evolve through reproduction into forms that are better suited to their environments. Notice that the driving force behind evolution is comfort. What exactly do we mean by comfort? Human comfort is affected by four environmental variables: air temperature, relative humidity, radiation and air movement. Each of these variables has an effect on the heat balance of our bodies.
We feel comfortable when the heat generated inside our bodies just balances the heat loss from our skin. Physiologists have measured the effect of each of these variables and have devised a diagram they call the human comfort zone. This is defined as the range of air temperatures and relative humidity over which the average sedentary person in ordinary indoor clothing feels neither too hot nor too cold. You'll be amused at one of the ways early comfort scientists originally obtained their data. Without informing their factory-worker subjects, they measured productivity while varying the temperature and humidity in the factory. When production fell off, it was assumed the workers were uncomfortable. Can't fault the logic! But married couples know that two people can sit in the same area and one will be comfortable while the other complains of the cold. Obviously, there is a degree of variability between individuals. There are also cultural, regional and seasonal differences; witness Darwin's observation of the natives of Terra del Fuego sweating by a fire Darwin had lit to stay warm. I have witnessed residents of Miami wearing ski parkas when the temperature dropped to 60° and Maine natives wearing shorts on a rare 50° day in February.
We have to take the comfort zone as an indication of relative comfort, but the principle holds true. According to the comfort zone, the average person is comfortable within the temperature range of 72° to 78° F and a relative humidity range of 20 to 70 percent. Beyond these limits we generally turn on the heating system, air conditioner, humidifier or dehumidifier. Temperature and humidity are not the only factors affecting comfort, though. The comfort zone is shifted upward by air movement and downward by radiation (either artificial or solar). A breeze removes heat from our skin and so lowers the apparent temperature by about one degree for each mph of speed up to about 5 mph. On the other hand, radiation adds heat to our skin and lowers the comfort zone by approximately 20° per solar equivalent (full sunshine or its equivalent). Our ancestors were attuned to the effects of wind and sun. Ancestral man chose for his home a wind-sheltering cave facing the sun and supplanted the sun at night with fire. Today, we build homes facing the street instead of the sun and have replaced fire and breeze with central heat and air conditioning. But overcoming nature with brute-force energy systems is unnatural. Sitting next to a radiator doesn't compare to sitting in the sun, nor will a fan ever replace a natural breeze.
In spite of our technical ability to create any set of conditions we desire, our homes will be truly comfortable only to the degree that they work with climate rather than overcome it. Designing a house that works with climate means optimizing its thermal response to the climate. In a cold, cloudy area you would install as much insulation as would pay for itself in fuel savings, but you would not include more energy-leaking glass than required for natural daylighting and view. In a cold, sunny area you would want an area of south-facing glass that would collect just enough solar radiation to heat the house through a cold, clear winter day - yet not overheat it. In an engineering sense, designing for climate implies that we can quantify it, and we can. Climate is measured by the same four variables that define the human comfort zone: temperature, relative humidity, wind and solar radiation. The United States covers an area of roughly 3,500,000 square miles and includes climates ranging from tropic to arctic.
In addition to its 700 official weather stations, the National Weather Service employs 13,000 volunteer observers to collect climate data. This sounds like a lot of data, but it amounts to just one observation site per 270 square miles. Where I live on the coast of Maine, the temperature at noon on a summer day can be 75° at the shore but 90° just 10 miles inland. For this reason and others, climatologists break climate into two distinct categories: macro (large-scale) and micro (small-scale). We'll concentrate first on the big picture - the macroclimate. We'll look at the equally important microclimate in the next chapter. Macroclimate The official repository of weather records, the National Climatic Data Center, maintains a website (www.nndc.noaa.gov/cgi-bin/climaps/climaps.pl) where you can view and download macroclimatic maps in PDF format. I've downloaded the maps most useful for the purpose of selecting a home site. As you look at them, ask yourself two questions:
1. Would I be able to enjoy my favorite outdoor activities under these conditions?
2. What features of a house would allow it to sail effortlessly through these conditions?
Map 1 shows the mean, daily high temperature in the month of July. With the exception of mountainous areas in the southwest, the climates of the entire southern tier of states lie outside the human comfort zone for strenuous outdoor activities due to excessive heat. Were you to build your house there, a primary consideration would be cooling.
Map 2 shows the mean high temperature for January - quite a different picture! We can deduce from the map that there would be extended ice fishing and snowmobiling seasons in the northernmost states, and that homes there require thick insulation, high-R windows, and strong, snow-supporting rafters. We can also see that homes in the two southernmost zones would require only space heaters to get through the winter.
Map 3 is a predictor of your cooling bill. An average daily temperature of one Fahrenheit degree over 65 is counted as one cooling degree day (CDD); a day with an average temperature of 75° F would then count as 10 cooling degree days. The map shows accumulated cooling days for the entire cooling season. Looking at the map you can see that a cooling bill in Key West, Fla., (3,500 CDD) would be approximately seven times as great as it would be in Boston (500 CDD). Unless, of course, the Key West house were designed to reflect the heat of the sun and to have high "thermal inertia" due to masonry construction.
Map 4 shows heating degree days, the annual sum of deficits of average daily temperature below 65°. The analogous theory is that the amount of fuel a house will require is proportional to the heating degree days of its climate. Again, unless you were to design the house to utilize free solar heating and insulate it heavily to minimize heat loss. Maps 5 and 6 are for gardeners.
Map 5 shows the average date of the last killing frost in the spring; Map 6 shows the date of the first frost in fall. The difference between the two dates is the length of the growing season.
Don't forget, however, that we are talking averages, or macroclimate, here. In the next chapter, you will see how the microclimate can effectively shift your site and garden as much as 1,000 miles north or south.
Map 7 shows mean relative humidity for the month of July.
Whether a region is outside the comfort zone depends on both relative humidity and temperature, so you have to consider both Maps 1 and 7. Most of New England, the upper Midwest and the Northwest fall within the comfort zone for both humidity and temperature and so require no mechanical cooling. The Gulf Coast region is both too hot and too humid, so it requires both cooling and dehumidification. Most of the remainder of the country is too hot, but there is a huge difference in relative humidity, roughly east and west of a vertical line dividing the country. East of the line, we must employ air conditioning to cool air, but west of the line the air is dry enough to employ a low-tech device, the evaporative cooler. The "swamp cooler," employs the same trick that cools the atmosphere after a thunderstorm: simple evaporation of water. Hot, dry air blown through a wet fabric emerges more humid but at least 20° cooler. Evaporative coolers will, no doubt, be used increasingly in the Western United States because they consume a third (or less) the electricity of air conditioners. These seven macroclimatic maps should give you enough information to pick a region of the country fitting your idea of a healthy climate. In the next issue's installment we will consider the amazing abilities of topography and vegetation to create a microclimate within the larger climate -effectively moving your site hundreds of miles north or south of its geographic location.