How Do Geothermal Heat Pump Systems Work?
Tuesday, December 8th, 2009

The parade home built by Durrett Interests at 4229 Camacho Street in Mueller was recently featured by EcoHome Magazine as one of their online case studies. Designed by Barley & Pfeiffer Architects and verified by Contects Consultants, the home earned LEED-Platinum, NAHB-Gold, and Austin Energy Green Building 5-Star Certification, plus Energy Star Qualification. Click here to view a PDF of the EcoHome case study or click here to view a slideshow of our parade home photos.
What is Indoor airPLUS?
EPA created Indoor airPLUS to help builders meet the growing consumer preference for homes with improved indoor air quality. EPA developed additional construction specifications to help improve indoor air quality in new homes. Construction specifications include the careful selection of and installation of moisture control systems; heating, ventilating, and air-conditioning systems; combustion-venting systems; radon resistant construction; and low-emitting building materials. Ask about the Indoor airPLUS qualification for your next new home.
How Does a New Home Become Indoor airPLUS Qualified?
A builder must first design a home to earn the ENERGY STAR label — the government-backed symbol for energy efficiency. The result is a home that is significantly more energy efficient than a home built to minimum code, helping reduce greenhouse gas emissions. To earn the Indoor airPLUS label, the builder then adds up to 30 home design and construction features to help protect qualified homes from moisture and mold, pests, combustion gases, and other airborne pollutants. Before the home officially earns the Indoor airPLUS label, it is inspected by an independent third-party to ensure compliance with EPA’s rigorous guidelines and specifications.
Durrett Interests recently obtained Gold ratings from the NAHB Green Building Program for all four condominium residences built at Wooldridge + 29th in Pemberton Heights, Austin. The homes feature between 1,951 and 2,682 square feet of living area and are priced between $774,575 and $874,575.
"We are thrilled this project achieved Gold ratings with the NAHB’s new green building program," said Marshall Durrett, president of Durrett Interests. "This has been a very challenging project to execute, for a number of reasons, but it’s very rewarding to have such great results. We will display our certificates with much pride in our office."
Notable green building features of Wooldridge + 29th include indirect daylighting, light colored roofing, spray foam insulation, high efficiency air conditioning, low-VOC interior finishes, tankless hot water heaters, dual flush toilets, and compact fluorescent light fixtures.
Chip Henderson and Elton Chessman with Contects Consultants of San Antonio performed the green building rating services for this project, which consisted of verification of construction durability measures and inclusion of prescribed green building features. Services provided by Contects also included testing of the home’s performance upon completion to verify that it was indeed built to the level of energy efficiency required by each green building rating program.
ABOUT NAHB GREEN: Through the National Green Building Program, the National Association of Home Builders is helping its members move the practice of green building into the mainstream. Energy efficiency, water and resource conservation, sustainable or recycled products, and indoor air quality are increasingly incorporated into the everyday process of home building. The National Green Building Program offers several resources and tools to help builders, remodelers, home building associations, and homeowners learn how to build green, and the benefits of doing so.
I took these three product photos at our parade home in Mueller. This house boasts a 5-star green building rating from Austin Energy, gold rating from NAHB’s new green building program, and certification by LEED. Mueller is a sustainable, transit-oriented Central Austin community that includes a broad range of homes plus places to shop, dine, jog, bike and play.
The first photo displays a recessed can light fixture that is specifically designed for use with compact fluorescent light bulbs (CFL’s). This specific fixture only allows for CFL’s with a pin-type connection versus a screw-in connection, thereby preventing the end user from swapping out the CFL’s for incandescent light bulbs. Just one CFL will save about $30 over its lifetime and pay for itself in about 6 months. It uses 75 percent less energy and lasts about 10 times longer than an incandescent bulb.
CFL’s produce light differently than incandescent bulbs. In an incandescent, electric current runs through a wire filament and heats the filament until it starts to glow. In a CFL, an electric current is driven through a tube containing argon and a small amount of mercury vapor. This generates invisible ultraviolet light that excites a fluorescent coating (called phosphor) on the inside of the tube, which then emits visible light.
CFL’s need a little more energy when they are first turned on, but once the electricity starts moving, use about 75 percent less energy than incandescent bulbs. A CFL’s ballast helps "kick start" the CFL and then regulates the current once the electricity starts flowing. Older CFL’s used large and heavy magnetic ballasts that caused a buzzing noise in some bulbs. Most CFL’s today use electronic ballasts, which do not buzz or hum.
This next photo displays a low-profile smoke alarm on the left and a low-profile carbon monoxide alarm on the right, both from the Silhouette line by Kidde. Silhouette smoke and carbon monoxide alarms blend in effortlessly with their surroundings. Their unique, square shape protrudes less than half an inch from the ceiling, allowing them to virtually disappear.
Both alarms run off the home’s electricity, and contain rechargeable batteries for backup power during power outages. The alarms will also link with other alarms to create an interconnected system so that when one alarm sounds, all of the alarms sound, offering an earlier warning throughout the home. Today’s building codes usually require that newly constructed homes have hardwired, interconnected smoke alarms with battery backup.
Silhouette alarms contain a sealed, rechargeable battery that lasts the life of the alarm, meaning homeowners never have to replace a battery. While homeowners will enjoy the low maintenance and look of Silhouette, the builder will benefit from an easy installation and fewer callbacks. These UL-approved, hardwired alarms are a distinctive home feature that will serve as an exceptional upgrade option for remodels and new construction.
This last photo displays a curved blade metal supply register for heating and air conditioning. Curved blade ceiling registers are recommended by most green building programs because of their ability to better distribute heating and air conditioning throughout the home than their more traditional counterparts. Because of their more exaggerated metal fins, much like the rear spoiler on a race car, curved blade registers more effectively force the heating and air conditioning where needed in the home.
This is important because common practice in Austin is for ceiling supply registers to be mounted closer to a room’s interior walls so that the supply air may be "thrown" along the ceiling and toward the outside wall with windows. This practice is common because windows are where most of the heat gain in a home is realized in our climate. Throwing air conditioning onto windows "washes" them in cooler air and helps to keep their surface temperatures lower, thereby reducing heat gain into the home.
A contemporary home in Tarrytown that was designed by Hugh Jefferson Randolph, AIA and built by Durrett Interests, LLC is now featured on NanaWall’s website in their project library. NanaWall is a unique solution that provides constant options for open air living or weather-tight comfort in today’s elegant homes. The secure shelter of the closed NanaWall transforms to breathtaking, unobstructed wide open space in moments. Indoor-outdoor boundaries vanish, living space expands, and broad vistas or quiet gardens become an integrated part of the home. NanaWall embraces the values of today’s cutting edge architecture. The NanaWall is engineered for energy efficiency from environmentally friendly materials. A NanaWall incorporates sustainable design features such as natural lighting and ventilation into every project in which it is featured. In addition, concealed hardware, maximized glass area, and a single floor track create clean, unobstructed architectural lines. View our project library listing.