Green building’s surprising energy savings
“Usecommon sense to make sense.”
It soundslike Ben Franklin, but the speaker in this case is David Johnston, agreen-building consultant in Boulder, Colo. His Ben Franklin-sounding aphorism,he said in a recent interview, has proved to be a useful, shorthand way ofexplaining sustainable green-building principles and practices.
Althoughthese have been embraced by more and more home builders, there is still muchconfusion among the general public as to what exactly makes a house green. Oneway to keep things straight, Johnston said, is simply to remember to “usecommon sense to make sense.”
Forexample, Johnston is regularly asked if a green house is one that ispetroleum-product-free. His common sense answer: “If you eliminateeverything that contains petroleum, you can’t enjoy the accoutrements of a 21stcentury lifestyle.” All the heating and cooling equipment and standardappliances contain plastic, he pointed out, adding that “even something asbasic as a toilet has plastic parts.”
Themake-sense part of green building, Johnston went on to say, has to make senseboth environmentally and economically. For example, building materials thathave recycled content are generally considered to be a plus because recyclingcan significantly reduce both the volume of the waste stream and pressure onoverflowing landfills.
But,speaking like the hard-headed home builder that he once was, Johnston said youshouldn’t select a product solely on this basis. A product with recycledcontent may be much more costly than the conventional product it is intended toreplace, and it may not perform any better.
Materialshave to make sense from a health perspective as well, Johnston said. Manybuilding materials are made with unstable, volatile organic compounds, calledVOCs. They can off gas into the air for weeks and sometimes years after theyare installed in your house. Of the hundreds of VOCs that have been identified,the one that concerns most people is formaldehyde, a potent eye and noseirritant that can cause respiratory problems. It has been classified by theWorld Health Organization as a confirmed human carcinogen. You can easily avoidit by using one of the many building products now available with low or no VOCcontent, Johnston said. Though the non-VOC products often cost more, this isone instance where a higher cost is worth it, he added.
Segueingfrom materials to other aspects of green-home builders Johnston talked abouthousehold energy use. His common sense rule: Use as little as possible. Hiscommon sense reason: to save money and the planet. If you use less energy,you’ll save money on your utility bills. You’ll save even more as the price ofnatural gas, fuel oil and electricity inevitably goes up.
If you useless energy you’ll help save the planet because you will be reducing thegreenhouse gas emissions associated with your house. Unbeknownst to mosthomeowners, buildings are the largest source of the greenhouse gas emissionsthat are causing global warming. In the United States, half of building-relatedemissions are from houses.
Johnstonfeels that energy issues are so important, he urges homeowners to put themfront and center in the design of any new house — “from the first sketchof a floor plan to the final dotting your I’s and crossing your T’s.”
But,Johnston hastened to say, energy savings should not come at the cost of havinga great-looking house with lots of windows and great views. The trick is to getall this and save energy.
Johnston’scommon sense strategy for supplying household energy needs: Use what’s freebefore using what you have to pay for. That is, tap as much free solar energyas you can for your heating and lighting needs before turning to conventionalsolutions.
To dothis, you really do have to think about energy from the start because thefeasibility of passive solar solutions depends on how you place your house onyour building site, the first step in any building project. To capture thesun’s rays for heating your house during the winter, your living areas must beoriented to the south. You can keep the same spaces cool in the summer by addingoverhangs. With some additional refinements to the overhangs, the sun can alsosupply your lighting needs during the day.
Tomaximize the benefit of passive solar heating and cooling, you need tocarefully tailor your building envelope to reduce heat loss or heat gainthrough the walls and roof. This generally requires adding insulation to thewalls, attic and basement in amounts far above code requirements and upgradingwindows to get ones with a low-emission coating that helps to keep the heatinside during winter and outside in summer.
Unless youlive in Hawaii or Santa Barbara, Calif., where passive solar strategies cansupply all your heating and cooling needs, you’ll still need a furnace forthose cold days when the sun’s heat is not enough to keep you comfortable. Butwith your upgraded building envelope, you can use a smaller furnace and airconditioning condenser, and that is a cost savings, Johnston said.
You’llalso need electric lights for nighttime use and cloudy days. Surprisingly,lighting accounts for about 12 percent of household energy use in the averagehousehold. Solar daylighting shaves part of this, but you can shave it furtherwith compact fluorescent bulbs, commonly called CFLs, Johnston said. They useabout 75 percent less energy to produce the same amount of light as anincandescent bulb, and they last six to eight times as long. CFLs can bescrewed into almost any conventional light socket and their color correctionhas vastly improved in recent years.
The otherpart of the home energy puzzle that green building can affect is the sizeableenergy draw for hot water. The luxury of having 40 to 50 gallons available 24/7consumes another 12 percent of household energy use. But, Johnston said, it’sanother instance where you can tap free solar energy by installing a solarcollector on your roof. For those cloudy days, though, you’ll need a backuphot-water heater.
The other35 percent of the energy that the average household consumes is out of abuilder’s hands, because it is the “plug loads” that homeowners bringinto the house when they move in — appliances, computers, home-entertainmentequipment, and all the other doodads that most households accumulate. The mosteffective way to reduce this load is to purchase Energy Star products, nowavailable in more than 40 categories.
How doesJohnston’s “common sense to make sense” work in real time on a realhouse?
To findout I contacted McStain Neighborhoods, a small production-home-building firm inBoulder that has built sustainable, green houses for more than 40 years. Thefirm builds about 350 houses a year in the Denver and Boulder markets.
Like allhome builders, McStain evaluates everything from a cost-benefit perspective.But, unlike almost all the others in the United States, McStain has a researchand development department that carries out in-depth reviews of about 50 newproducts and building techniques a year. Periodically, the firm builds a testhouse that incorporates the most promising of these innovations. The test housesare eventually sold, but the firm continues to monitor them for several yearsafterwards, said McStain marketing head Barr Hall.
JeffMedanich, who heads up McStain’s research efforts, said that much of his workis a balancing act, spending more here but saving more there so that in sum,the cost of an innovation is relatively small.
Medanichoffered as an example McStain’s current exterior wall construction. Instead ofthe dimensional wood studs that are used by most home builders (a single pieceof wood sawn from a tree log), McStain uses finger jointed studs, which aremade up of several smaller pieces of recycled scrap lumber that are gluedtogether. These cost more but their superior quality means that fewer aretossed as unusable — only about 4 percent compared with 20 percent of thedimensional studs. The cost difference is a wash, but the finger-jointed studshave the added benefit of lowering costs down the line. Because they arestraighter, the walls are plumb, and this makes the work of subsequent tradesgo more smoothly and faster.
Questionsor queries? Katherine Salant can be contacted at www.katherinesalant.com.
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Copyright 2007 Katherine Salant
