LEED-Platinum House in a Warm Climate
General Specs and Team
Location: Weatherford, TX
Living Space : 2038 sqf
Cost (USD/sq. ft.): $117/sqf
Builder: Ferrier Builders, Inc./Ferrier Custom Homes, LP
Architect/designer: Gary Olp, GGO Architects
Energy consultants: Building Science Corp.
Foundation: slab on grade
Walls: 4.5-in. SIP(SIP) Building panel usually made of oriented strand board (OSB) skins surrounding a core of expanded polystyrene (EPS) foam insulation. SIPs can be erected very quickly with a crane to create an energy-efficient, sturdy home. wall (R-24.3)
Windows: double-pane, low-eLow-emissivity coating. Very thin metallic coating on glass or plastic window glazing that permits most of the sun’s short-wave (light) radiation to enter, while blocking up to 90% of the long-wave (heat) radiation. Low-e coatings boost a window’s R-value and reduce its U-factor., gas-filled (SHGCSolar heat gain coefficient. The fraction of solar gain admitted through a window, expressed as a number between 0 and 1. .27, R-3.2)
Roof: 8.25-in. SIPs (R-33.5)
Garage: none (carport)
Cooling: air-source heat pumpHeat pump that relies on outside air as the heat source and heat sink; not as effective in cold climates as ground-source heat pumps. (20 SEER(SEER) The efficiency of central air conditioners is rated by the Seasonal Energy Efficiency Ratio. The higher the SEER rating of a unit, the more energy efficient it is. The SEER rating is Btu of cooling output during a typical hot season divided by the total electric energy in watt-hours to run the unit. For residential air conditioners, the federal minimum is 13 SEER. For an Energy Star unit, 14 SEER. Manufacturers sell 18-20 SEER units, but they are expensive.
Water heating: (2) solar Collectors (Solargenix), 80-gal. hot water heater with internal heat exchangerDevice that transfers heat from one material or medium to another. An air-to-air heat exchanger, or heat-recovery ventilator, transfers heat from one airstream to another. A copper-pipe heat exchanger in a solar water-heater tank transfers heat from the heat-transfer fluid circulating through a solar collector to the potable water in the storage tank. and a supplemental 10-gallon drain-back tank (RHEEM Solaraide)
Annual energy use: 51.4 MMBtu
- Solar hot water collectors with 80-gallon indirect water heaterWater heater that draws heat from a boiler used for space heating; a separate zone from the boiler heats potable water in a separate, insulated tank via a water-to-water heat exchanger. See tankless coil. (cost: $5,600)
- CFLCompact fluorescent lamp. Fluorescent lightbulb in which the tube is folded or twisted into a spiral to concentrate the light output. CFLs are typically three to four times as efficient as incandescent lightbulbs, and last eight to ten times as long. CFLs combine the efficiency of fluorescent light with the convenience of an Edison or screw-in base, and new types have been developed that better mimic the light quality of incandescents. Not all CFLs can be dimmed, and frequent on-off cycling can shorten their life. Concerns have been raised over the mercury content of CFLs, and though they have been deemed safe, proper recycling and disposal is encouraged. lighting fixtures
- Energy StarLabeling system sponsored by the Environmental Protection Agency and the US Department of Energy for labeling the most energy-efficient products on the market; applies to a wide range of products, from computers and office equipment to refrigerators and air conditioners. ceiling fans and appliances
- Windows laid out for optimal daylightingUse of sunlight for daytime lighting needs. Daylighting strategies include solar orientation of windows as well as the use of skylights, clerestory windows, solar tubes, reflective surfaces, and interior glazing to allow light to move through a structure.
- Chimney effect of stairwell and window layout provides natural cooling, ventilation
- Attic fans
- Programmable thermostats
- Translucent roof in exterior storage areas for natural daylighting
- 3,000-gal. rainwater catchment system for flushing toilets and irrigation
- Dual-flush toilets (1.6 GPFGallons per flush. Measurement of water use in toilets. Since 1992, toilets sold in the United States have been restricted to 1.6 gpf or less. The standard for high-efficiency toilets (HETs) is 1.28 gpf. / 0.9 GPF)
- Low-flow faucets and showerheads (Delta)
- XeriscapingType of landscaping that requires little if any irrigation; suited to dry and drought-prone climates; generally relies on regionally adapted native plants. with native plants
- High-efficiency washing machine & dishwasher (Kenmore)
Indoor Air Quality
- Gas burning, direct-vent, sealed-combustion fireplace
- Interior paints and sealers contain no or low VOCsVolatile organic compound. An organic compound that evaporates readily into the atmosphere; as defined by the U.S. Environmental Protection Agency, VOCs are organic compounds that volatize and then become involved in photochemical smog production.
- ERV(ERV). The part of a balanced ventilation system that captures water vapor and heat from one airstream to condition another. In cold climates, water vapor captured from the outgoing airstream by ERVs can humidify incoming air. In hot-humid climates, ERVs can help maintain (but not reduce) the interior relative humidity as outside air is conditioned by the ERV. with HEPA filters
- FormaldehydeChemical found in many building products; most binders used for manufactured wood products are formaldehyde compounds. Reclassified by the United Nations International Agency for Research on Cancer (IARC) in 2004 as a “known human carcinogen."-free cabinetry
Green Materials and Resource Efficiency
- Fiber-cement siding, wood debris, and drywall scraps ground into mulch
- Fiber-cement and stucco siding
- Metal roofing and exterior trim
- Carpet contains 80% recycled-content P.E.T. fibers
- Regionally harvested white oak (a fastest-growing hardwood) for cabinetry
- Bamboo flooring at stairs & landing
- 100% pervious site outside home’s footprint
- Locally harvested stone from retaining walls & walking paths
- FLOR carpet tiles (biodegradable, made of recycled corn husks)
LEED for HomesLeadership in Energy and Environmental Design. LEED for Homes is the residential green building program from the United States Green Building Council (USGBC). While this program is primarily designed for and applicable to new home projects, major gut rehabs can qualify. points (earned/available): 90/108
This striking contemporary home is a model of sustainability on a budget
This north-Texas contemporary home earned the third-ever LEED for HomesLeadership in Energy and Environmental Design. LEED for Homes is the residential green building program from the United States Green Building Council (USGBC). While this program is primarily designed for and applicable to new home projects, major gut rehabs can qualify. Platinum certification — but it could possibly share the award. The design of the LEED-H pilot home was inspired by architect Gary Olp's own energy-efficient house. Heather Ferrier, general manager for Ferrier Custom Homes, fell in love with Gary's place and enlisted him to rework the design into an affordable, comfortable, and sustainable home for her. Heather's father Don, who also built Gary's house, then set out to build his daughter's dream home.
Plan on letting nature work for you
Gary and Don have been building sustainable homes for years, and understand that an integrated plan exploiting the skills and experience of a diverse team will give them the best house for the money. This included tapping into the resources of the Dept. of Energy's Building America program and the expertise of consultants at Building Science Corp.
They worked together to adapt the basic concepts of Gary's home into a more compact and affordable design. The home's low energy demand relies on using as much of nature's resources as possible. Tall open spaces create a chimney effect, drawing natural cooling breezes through thoughtfully placed windows. There is an air conditioner for hotter days, but its variable speed fan and automated controls help keep its power use well below average.
The abundance of windows and bright white walls let sunlight spread to every corner of the house. In winter, when the sun is low, it peeks under the home's awnings and decks, shines directly on the concrete floors and warms the house. The sun also heats most of Heather's hot water through solar panels on the roof.
Where you build affects what you build
The house sits on a south-facing urban infill lot. Ferrier Custom Homes spared every tree - including two large Indian Oaks. During the winter, when they shed their leaves, these trees allow sun in to assist with heating the home; in summer, they entirely shade the west facing windows. But overall the sunny site didn’t offer enough protection from the summer heat, so Gary penned several porches and overhangs into the design for some manmade shade.
The slope of the site and the metal roof set the stage for the installation of an underground rainwater collection system. The 3,000-gallon collection tank irrigates the garden and provides non-potable water to the house.
Materials make a difference
If you want to create a healthy and comfortable home while saving resources and energy, the materials you build with can be as important as how you build. In Heather's home, structural insulated panels (SIPs) create an economical shell that helps keep the place comfortable year round. Reflective metal roofing tempers the hot Texas sun and should give many years of service before it could eventually be recycled. Stained and sealed concrete was used for the floor, not just for its low price and good looks, but also for its valuable thermal massHeavy, high-heat-capacity material that can absorb and store a significant amount of heat; used in passive solar heating to keep the house warm at night. . All interior surfaces, including finishes, adhesives, flooring, laminate countertops, and even draperies were chosen because of their good scores on indoor air quality and sustainable manufacturing.
Good ideas can be contagious
There was enough talk about Heather's home before construction even started to get it into the LEED for Homes pilot program and onto the U.S. Dept. of Energy's Building America list of 2006 prototype homes. During and after completion it was featured in numerous news stories and was even open for public tours. Heather is no stranger to sustainable homebuilding, but reflecting on the overwhelmingly positive response, she mentioned that in her region "you don't see that many projects like this." With her inspiring example, hopefully that will soon change.
Use science and experience
Although Heather's home was inspired by Gary Olp's house, differing site conditions and materials required unique solutions. Because Heather's site is sunnier and her SIPs don't temper heat gains like the ICFInsulated concrete form. Hollow insulated forms, usually made from expanded polystyrene (EPS), used for building walls (foundation and above-ground); after stacking and stabilizing the forms, the aligned cores are filled with concrete, which provides the wall structure. walls in his house, Gary understood that sheltering overhangs and a lower proportion of windows would be necessary to keep Heather's home cool.
Energy modeling by Building Science Corp. helped pinpoint the right amount of glass (about 15% of total square feet) to fine-tune the home's energy efficiency. Jane Talkington at Oklahoma State University used a scale model to study seasonal sun exposure, influencing the placement of windows and awnings. The modeled performance of the initial design was 43% more efficient than the IECC International Energy Conservation Code. Model Energy Code. Slight changes to the plans boosted projected efficiency by another 8%.
People have to know about green homes to like them
Some of the biggest surprises were in people's reactions to the project. After a show of interest from friends and colleagues, Ferrier Custom Homes decided to document the construction of Heather's home and work with a local newspaper to tell the story. Heather had not planned to use the house for public relations, but as curiosity about the project grew, she decided to open it for public tours. Early on, she hosted tours of 100 to 200 people, but on the last open day, about 5,000 visitors showed up to see the house.
People were apparently intrigued by the idea that a young single person on a tight budget could build a green home. The obvious focus on energy efficiency and the more recently popular concern for using local and renewable resources seemed to be the initial sources of public interest. "One of the first comments I heard from many of the visitors was ‘this house feels really happy'," Heather said. Perhaps the bright, airy spaces and warm, natural materials opened people's eyes to the fact that one of the most important qualities of a truly green home is comfort.
- Bjorn Wallander
- Heather Ferrier
- Toshi Woudenberg
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