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Home , Passive house

gNI A certified passive uses about 90% less energy for heating and cooling than the average home.

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22 E MAGAZINE NOVEMBER/DECEMBER 2010 The New Passive Are S ~ -r y- ff'c'- t, T -y Make Heating and Cooling 'r-ct'c- y rr- -v- t

By Christine MacDonald

or Hunter Duplantier, the tuturistic-looking house that iveilt up last winter on the edge of the University of campus in Lafayette stood out among its traditional-looking neighbors. It' built like a loft, tall and boxy, with a tlat roof and oddly placed nar- row windows. Itut the most unusual attributes of the home were the ones he couldn't see. The is the first in the southern U.S. to achieve official certitication as a "." As such, it needs a mere fraction of the elec- tricity it takes to run a consentional home of comparable size. Once it was We Nottlngham completed last spring, Duplantier and two other architecture students enthu- ',H.O.U.S.E, siastically volunteered to rent the and monitor its performance. 'Houfe place They the ., I11oved in during finals week, embarking on an experiment in low-energy liv- Use of Solar .g ing that simultaneously harkens back to the super-insulated-house movement Energy) Is a ., of the '70s and provides a look at how we ati might live in a peak-energy ftiture. modular passive "'IA'e house ttesigned were just in awe, just overwhelmed with information at tirst," . andbulltby Duplantier says. After spending a record-breaking hot summer there, h» from' "held tvell far." R the,UK's reports, the home has up pretty so of

E MAGAZINE NOVEMBER/DECEMBER 2010 a3 '.-'g

A PASSIVE HOME PRIMER Conventional lose inside heat and air- conditioned air via ill-fitting windows and doors and allow outdoor temperatures to seep inside through leaky walls, ceilings and floors. That ratchets up a home's footprint—and the household energy bills. Iiuilders typically use insulation and tighter-fitting windows to cut ~iA'g down on such air leakage, and increasingly employ one or more of the much ballyhooed stars of today's rapidly growing U.S. green build- \ ing marketplace: solar panels, geothermal heating i;P+.t systems, windmills and other so-called "green bling" that reduce a house's carbon footprint by generating homemade . t A passive house offers a different approach- and philosophy—about how to achieve the same 1 ~' ~Qil low-carbon lifestyle. Instead of reducing emissions by generating alternative power, these buildings E simply don't require much . They are so airtight that it takes little more than the inhabi- tants'ody heat to warm them up in cold , while in hot ones like Louisiana, the emphasis is on not letting the sticky outside air permeate the building's "envelope," industry parlance for the four walls, roof and ceiling. Considering that nearly half of U.S. green- O~ M house gas emissions come from our homes (48%, to be exact, according the U.S. Energy / Information Administration), and that roughly half of the nation's electricity comes from dirty coal-tired power plants, the passive house build- ing system is a major step forward in the fight against global warming. A certified passive house uses about 90% less energy for lieating and cool- ing than the average home, reducing total energy i consumption to between 60% and 70% less than a conventional home, accordinb| to the Passive House Institute U.S., an Illinois-based nonprofit group that promotes the building system and The first passive house in the South (top), located in steamy Lafayette, certifies U.S. buildings. Louisiana. Below: An energy-efficient heat-recovery system delivers fresh air "lt's the most aggressive standard in the world for energy efficiency," says California The 1,200-square-foot home is one of a growing number builder Rick Ivlilburn, contrasting it with U.S. initiatives such of passive houses being built around the country in sizes and as the federal program, which requires buildings architectural styles as varied as the climates where they'e sit- to perform just 15% more efficiently than conventional uated. A Maryland developer is putting up a 4,400 square- homes built to the 2004 International Residential Code. foot McMansion designed to perform like a passive house but "It's a serious commitment," agrees University of look like an American foursquare, those faux farmhouses Louisiana Professor Corey Saft, who built the house where popularized a century ago thanks to mail-order construction Duplantier lives."You have to be really clear that it's what you kits sold in the Sears catalogue. In New York City, meanwhile, want." The commitment begins before the foundation is another architect has embarked on the first-ever passive poured, which, for starters, must be sealed off and insulated retrofit of a genuine century-old townhouse. from the ground below. "It was a challenge," says Jeremy Shannon, the vice presi- Saft says he spent about 30% more on insulation than he dent of Prospect Architecture, PC., who convinced a couple would have in a standard construction project but saved on of Brooklyn homeowners to go passive instead of doing a the passive home's heating and cooling system, which is run-of-the-mill retrofit of their Park Slope brownstone. "4'e smaller and less costly than ones used in conventional both agreed he says of the owners, who want to remain homes. These houses are so tightly wrapped that they con- anonymous, "This is going to be a real extreme challenge. serve indoor temperatures much better, which means equip- Let's see if we can do it.'" ment doesn't have to work as hard to maintain a constant,

24 E MAGAZINE NOVEMBER/DECEMBER 2010 A PASSIVE HOUSE OFFERS A DIFFERENT APPROACH. INSTEAD OF REDUCING EMISSIONS BY GENERATING ALTERNATIVE POWER, THESE BUILDINGS SIMPLY DON' REQUIRE MUCH ELECTRICITY. comfortable environment. conventional home of comparable size in that zip code. Insteadofthestandardcentralairor ,thekeycom- Peabody thinks passive houses are better positioned to ponent of a passive house is its heat-recovery system. As the enter the mainstream than those "blingier" green homes name implies, heat from the home's outgoing polluted air is because they repurpose commonly used equipment instead of captured via a inside the home's ventilation requiring builders to learn a whole new skill set like how to units; incoming air is warmed by this exchanger as it enters. install solar panels or radiant heating systems that could saddle The home's heat is preserved, while still allowing a constant homeowners with maintenance nightmares. "There's nothing circulation of fresh outdoor air for improved indoor air qual- unusual about an ERV," he says, noting that the devices are ity. In parts of the U.S. where cooling and dehumidifying are often used in hospitals and office buildings. "What is unusual as much of a challenge as heating, Energy Recovery Ventila- is you are using it for your heating and cooling and to divert tors, or ERVs, are being used. Unlike straight heat-exchangers, that throughout the house. Our whole approach in this house i ERVs also transfer water vapor, which prevents the airmr from drymgdr in out in winter months, and a new passive home in Sonoma, California, has impressed owner Catherine removes indoor during summ p'ttettt with its quiet, warmth and low maintenance. months. ERVs allow for one-third',of the building's air to be replaced with fresh air every hour. ' Passive house proponents rave not only about e, the energy savings but also about the fresh air and «.'g: quietude. "As soon as the windows went in, the house became warm and quiet and peaceFul says &s ~pi 'e

Catherine O'eill, whose new home in Sonoma, c gjei&&gy California, built Milburn, became the first in by '~ v that state to earn passive house certification earli- ia"~/'hat se er this year. She says what really impressed her was „ 'c, iare the entire mechanical system fits into a space / p that she thought would be her linen closet.

LIVING ON THE CHEAP Katrin Klingenberg, executive director of the Pas- sive House Institute U.S., who built the tirst U.S. vtt r~ passive house in 2003 and has lived in it ever since, says her electric bills come to just $25 a month in the summer and $60 to $94 a month in the winter at her 1,000-square-foot home in Urbana, Illinois. Duplantier says that he and his roommates also paid just $25 a month for electricity over the sum- mer to supplement the energy generated by the home's 3.264-kilowatt rooftop thin-film solar pho- tovoltaic system. Solar panels aren't a given in pas- sive homes, but many projects include them since it takes far fewer solar panels to slash a passive house's carbon emissions to zero than would be needed for a conventional home. Duplantier expects to pay little or nothing for electricity dur- ing cooler months when he and his roommates can throw open the windows and turn oif the A/C. In larger homes, the expected savings can be eye-popping. Architect David Peabody, who is building a passive home called "The New Ameri- can Foursquare" in Maryland, has calculated that it will take about $700 a year to heat and cool its 4,400 square feet, compared to about $7,000 for a PERHAPS ONE OF THE REASONS IT HAs TAKEN so LONG FOR PASSIVE HOUSE DESIGN TO ESTABLISH ITSELF IN THE U.S. IS THE WIDE ARRAY OF CLIMATES, EACH REQUIRING SPECIFIC BUILDING MODIFICATIONS.

is to keep things simple, so it's not a lot of maintenance or a lot of unusual gad- gets," he says. "It's not a 'Look at me!'Gee whiz!'ype of house."

PASSIVE IS NOT ONLY FOR HOUSES Pioneered over the last two decades in , a passive house, known there as passiv/raus, doesn't have to be a house at alL In Europe, more than 15,000 homes, schools, hospitals and apartment and office buildings have been built to this standard, and passive design has entered local Enid regional building codes much in the way the U.S. Council's (USGBC's) Leadership in Energy and Environmental Design (LEED) has in this country. And beginning in 2020, the will require new buildings to produce nearly all the energy they consume, a sea change that is expected to fuel even more passive house growth abroad. It's hard to make an even comparison benveen LEED and passive houses. LEED takes a more holistic approach to green building—from how and where raw materials are pro- duced to finishing touches such as bike racks. Builders are allotted points for everything from solar panels to water-sav- ing installments to Fnergy Star kitchen appliances. Accumu- late enough points and your building qualifies for certifica- tion. Passive house certification operates on a pass/fail basis. Before certification, each building must pass a test, in which a is used to suck all the air out of the house to check for air leakages. To gain certification, buildings must be airtight, meet rigid heat recovery standards and use minimal energy. Extra bike racks or energy-efficient appli- ances won't make a difierence. Still, Klingenberg says, "LEED and passive house [stan- dards) are beautifully compatible." Her institute is lobbying Those earlier experiments lirxled out, perhaps due to ": for the USGBC to adopt passive house as its energy standard. problems with water condensation, mold and poor air qual- Such a move, she suggests, could resolve the public relations ity that arose precisely because they were so tightly built. * problems the organization has faced in recent years when Feist addressed those concerns with design improvements „ LEED certified buildings have failed to deliver on their and the addition of heat-recovery devices such as the ERVs. ) promised energy savings. It has taken a while for Feist's inspiration to make it b.ick ~ The building system is the brainchild of a German archi- across the Atlantic. Even after the first passive house went Up z tect named Wolfgang Feist, PhD, who founded the Pas- in 2003, the design was slow to catch on. 13ut that may be a sivhaus Institut in , Germany, in 1996. Feist has changing. Since the Passive House Institute U.S. opened its said that he took his inspiration from Amory Lovins of the doors in 2008, operating on a license granted by the German Rocky Mountain Institute, who was among the builders of institute, it has certified more than a dozen buildings and the first generation of super-insulated houses in the 1970s. several others are under construction, Rlingenherg says.

26 E MAGAZINE NOVEMBER/DECEMBER ZD ID crated by coils linked to the hot water heater, an operation " that requires about as much electricity as a hair dryer. g 11ie weather is just one of the idiosyncrasies oi'lace that " architects must deal with. Shannon, whose business involves (I performing a fair amount of retrofits, wrestled with how to $ insulate the hatch area leading into the basement of a centu- j The Hudson Valley Passive Project (left) resembles a ry-old New York City townhouse. In the end, he installed a 0 modern barn. A passive retrofit is being attempted on a door in the cellar wall and Laid down three inches of closed- g Brooklyn townhouse (above). "The New American cell insulation between the door and hatch. Still, as of Sep- rui Foursquare" in Bethesda, Maryland (top right) is 4,400 tember, the toivnhouse hadn't passed the blosver door test. *o square feet, but built to passive house standards. Nesv buildings minimize such challenges. With the Hudson Valley Passive Project, architect Dennis Wedlick is building a passive house in Claverack, New York, that resembles a mod- a wall of and a pine-beam arch. ADOPTING THE PASSIVE LIFESTYLE ern stone barn, featuring glass Perhaps one of the reasons it has taken so long for passive THE COST OF PASSIVE CONSTRUCTION house design to establish itself in the U.S. is the wide array of climates, each requiring specific building modifications. Like other green buildings, passive houses are more expensive The original German system, in contrast, is concerned to construct than conventional homes. Klingenberg's institute mainly with heating. estimates about a 10% price premium, though builders say Passiiv. house projects in places such as Maine and the the learning curve can raise costs by up to 25%. 13ut they iMidwest largely follow the German approach without much expect that to drop as architects, developers and subcontrac- modiiication, builders say. Skipping the ives tors gain experience. not an option in Louisiana, however. And, in Southwestern "The cheapest solution is clever and thoughtful design," states like New Islexico, a passive house design must take into says l3rian Uher, co-owner ofAmicus Consulting Services in account dramatic daily temperature swings. kensington. Mary(arid, who is one of a growing number of To meet the cooling and dehumidifying needs in construction industry professionals to receive training and Louisiana, Saft installed a one-ton mini split (small, - certification as a passive house consultant. less and easy-to-install) air-conditioning system coupled Milburn, the California developer, says he's "had to go with an ERV, as well as a device called a back-vented rain back to school in a couple of ways" to learn the passive house screen, which serves the dual purpose of shading the build- system, but adds: "Those are good problems to have." As an ing and allowing rainwater and condensation to escape industry, he says, "We'e been asked to build cheaper and outside and evaporate. cheaper anil our workforce has become less detail-oriented. In Bethesda, Maryland, a D.C. suburb with hot, mub»»y We need to relearn how to build buildings." summers and cold winters, Peabody installed an ERV and CONTACTS: I'assive House Institute U.S., www.passive mini splits in the basement and attic. Those units will be house.us; Passive House ventilation, http://www.passiv attached to ducts to pipe cool air or heat throughout his so- haustagung.de/Passive House E/ventilation 06.html; called "New American Foursquare" when needed. But that' Prospect Architecture, www.prospectarchitecture.corn. E just the backup s)stem. 1'he tive-bedroom house will have a "ground loop," a coil of tubing under the foundation that will CHRISTINE MACDONALD is an caviranmen/aljournalist heat incoming air in i»inter and cool it in summer before it arrd auijror ofGreen Inca An Environmental Insider Reveals enters the ERV. During colder months, heat will also be gen- How a Good Cause Has Gone Bad (The Lyons Press).

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