As Texans keep a close eye on the state's electrical grid during this record summer heat, one Austin-area neighborhood is staying relatively worry-free about blackouts.
Each home in Whisper Valley — located in Manor, about 8 miles north of the Tesla factory — comes equipped with solar panels on the roof and an underground geothermal heat pump that is more efficient at heating and cooling a home than an above-ground unit, said Greg Wolfson, chief financial officer of EcoSmart Solution, an affiliate of community developer Taurus Investment Holdings LLC. These two factors make Whisper Valley a zero-energy capable community. The development will eventually have more than 7,000 homes that are zero-energy capable.
The zero-energy capable label is not the same as the more commonly heard net-zero energy label, Wolfson said.
A net-zero energy home, over the course of a year, will produce as much renewable energy as it consumes, he said. While the zero-energy capable homes in Whisper Valley might not always meet that requirement, they come pretty close.
Whisper Valley is still connected to the state grid operated by the Electric Reliability Council of Texas. And it's just one community among the dozens under construction across the region, so its environmental impact is limited. But the building techniques employed at Whisper Valley, and the forethought displayed around resource use, foretell what may become standards for residential development amid a warming climate.
EcoSmart Solution uses the Residential Energy Services Network’s Home Energy Rating System Index as a benchmark for energy consumption.
The HERS Index is a measure of a home’s energy efficiency, according to RESNET. A score of 100 indicates that a home is as energy efficient as an ideal model home of the same size and shape, so the score is always relative to the size, shape and type of house.
The typical resale home scores 130 on the HERS Index, indicating that the home is 30% less energy efficient than RESNET’s model home. On the other hand, if a home scores a 70 on the HERS Index, it is 30% more efficient than the model home.
Homes in Whisper Valley target a HERS Index score of just 25, Wolfson said, “but many of our homes are in the teens, and some are actually below 10, which is very close to being a true net-zero energy home.”
Reaching this level of efficiency is accomplished through a combination of a geothermal system and solar panels that come with each home, Wolfson said.
Geothermal heat pumps in Whisper Valley and elsewhere use relatively constant underground temperatures to make the heating and cooling process more efficient.
“What the geothermal system does is it significantly improves the energy efficiency of the heating and the cooling … and also it preheats the domestic hot water,” Wolfson said.
These pumps use water to transfer heat with the earth rather than the air, making them more efficient.
While air temperature can swing to extreme hots and colds, the temperature of the earth is relatively constant, ranging from 45 degrees to 75 degrees, and is cooler than the outside air in the summer and warmer in the winter. That makes the transfer of heat to or from the system less taxing, Wolfson said.
The homes' solar panels are the other side of the zero-energy capable coin. Ideally, Wolfson said, homes will have to draw minimal power from the electrical grid, as the panels should capture enough electricity to power a home through the night.
Slideshow: Check out a 2017 tour of Whisper Valley below.
Homeowners in the development also have the option of installing an energy storage system and more solar panels on the roof. This can lead to a home becoming truly net-zero energy, Wolfson said.
Sustainability a a key area of development focus for Taurus, Managing Director Doug Gilliland said.
"For the consumer, these zero energy capable homes save them a lot of money on monthly energy bills by using the earth's natural energy to heat and cool their homes," he said. "It also provides protection against power outages or grid failures."
Kurt Stogdill, green building and sustainability manager at Austin Energy, said features like geothermal heating and cooling and solar panels helps increase the operational affordability of a home. These systems reduce energy demand at peak times, reducing the chance of outages.
The Whisper Valley system has been tested too, during the February 2021 winter storm that knocked out power across the state and contributed to hundreds of deaths.
“Whisper Valley homes used 54% less energy than other homes during the February 2021 freeze, reducing the strain on the grid,” Gilliland said.
Whisper Valley did lose power during that storm, Wolfson said, but for only three and a half hours on the first day.
While more energy efficient homes can benefit homeowners, they're also a boon for the state's electric grid, Stogdill said.
"Because we are connected to a statewide grid, increased efficiency for new and existing homes throughout the state would increase the efficiency of the state's electrical grid," he said.
Other ways a home could be made more energy efficient include smaller home designs, more insulation, better insulation installation and more efficient windows, Stogdill said.
Overall, Whisper Valley covers 2,063 acres. At full build-out, it is set to include about 7,500 single- and multifamily homes, as well as retail space, office parks, restaurants, entertainment venues and schools.
Whisper Valley is planned to be constructed in six phases.
TAURUS INVESTMENT HOLDINGS LLC
The neighborhood is being constructed in six phases, according to the Whisper Valley master plan.
Phase three and four lots are completed, Gilliland said, with home construction expected to begin by Sept. 1. Phase five is expected to begin in early 2023, and will include Whisper Valley’s first multifamily housing in the form of luxury apartments and build-to-rent homes.
Thus far, 380 homes are occupied in Whispery Valley and 443 have already sold.
The neighborhood will feature 160 acres of village-style retail, Gilliland said. The retail is well into the planning stage, he said, and the company hopes to have brokers market it to retailers and restaurants soon to catch up with the residential growth. There will also be 100 acres of neighborhood parks and a 600-acre Whisper Valley Park with nature trails, an amphitheater and event space.
Builders constructing homes in the neighborhood include Pacesetter Homes, GFO Homes, CastleRock Communities, Thurman Homes, AHA Dream Homes and Terrata Homes, Gilliland said. Avi Homes also built in the neighborhood during phase one.
Taurus is also selling parcels of land in the neighborhood, primarily in the rental market, Gilliland said. Companies that purchase the land will self-develop the property under the Whisper Valley master development plan.