Model home

Laverne Williams – architect
Ten years ago, long before it was fashionable, Bernadell and Stu Thompson built an off-grid ready house in San Antonio, Texas.

Now, everyone wants a tour.

“Even two years ago, we were considered way out there,” Bernadell said. “Now people are coming to us and asking, ‘How did you do this?'”

The 2,200-square-foot energy-efficient home is off-grid ready because solar panels are still too expensive compared to hooking up to the utilities which were already onsite. But that may change next year as costs fall, and the house is among the first in the San Antonio area to be certified by the Leadership in Energy and Environmental Design for Homes program, or LEED for Homes, which is considered the greenest of the nation’s green building programs.

The home, on 4 acres along the Guadalupe River, depends entirely on a rainwater-harvesting system for its water. Rain runs off of the metal roof and into a 10,000-gallon tank and a 5,000-gallon tank for storage.

The walls and roof of the home were built using structural insulated panels, known as SIPs, which essentially turn the house into an ice chest for energy savings thanks to a thick layer of polystyrene sandwiched between two pieces of engineered-wood board.

Deep roof overhangs protect the house from the heat of the sun – a technique that used to be common in Texas in the days before central air and heat.

“I wasn’t totally wanting to save the environment,” Bernadell said. “It’s just that this is a very practical way to build. A number of things on this building are what they used to do. It’s old technology that just makes sense.”

The home recently received a LEED silver rating. LEED uses third-party testing and requires a slew of paperwork to rank homes as certified, silver, gold or platinum.

LEED for Homes is an effort by the U.S. Green Building Council, which previously focused on commercial buildings, to encourage building homes using sustainable practices.

More than 10,150 homes across the U.S. are involved in the LEED for Homes pilot program, and 684 homes already have received LEED certification, according to the USGBC.

Architect LaVerne Williams of Houston’s Environment Associates Architects and Consultants said construction already had started when he learned about the LEED pilot program and asked the couple if they’d like to participate.

“We didn’t know when that program was going to start or what the requirements were going to be,” said Williams, who has been building green homes since 1975. “It was just a natural outgrowth of what they wanted to do.”

Passive sustainability

The biggest design challenge of the couple’s home is its location on a steep hilltop overlooking the Guadalupe River. Taking advantage of the best views of the river and Hill Country meant that big windows would need to face the southwest – the worst possible orientation for hot Texas summer afternoons.

Ideally, homes should be oriented to the south.

“The biggest issue on their house was how to capture that view without having a huge energy gain,” Williams said.

To solve the problem, Williams designed a deep roof overhang to shelter the home. In the winter when the sun is lower on the horizon, light can come into the living room windows and provide passive solar heating. The energy-efficient windows allow little heat transfer, but the house still probably won’t fall below 55 to 60 degrees even if the heating system is turned off.

“The main thing this house is designed on is passive sustainability,” Williams said. “They can live in this house in relative comfort without water or power. Even if they don’t have electricity for some reason, the house will stay cool in the summer, warm in the winter.”


The home’s SIPs, which were manufactured in Fredericksburg, also help prevent heat gain in the summer and heat loss in the winter.

The walls are 6 inches thick and the roof is 8 inches thick. And the insulated, sealed roofline means the attic stays the same temperature as the house.

“There’s no bugs, no dirt, no heat and humidity. The whole attic is a closet.”

Relying on rain

Although the couple moved into the home late last August – just in time for the drought to start – their water supply hasn’t been a problem.

Every inch of rain yields about 2,000 gallons of water for the home.

“We’ve had a really dry year,” Bernadell said. “If we get three-quarters of an inch of rain, we’ll be topped off on both tanks.”

Of course, they don’t leave the faucets running recklessly or take 30-minute showers. The couple bought low-flow toilets and a high-efficiency dishwasher and put aerators on all of their faucets. Their washing machine is a front-loading model that uses around 14 gallons per load, compared with the 45 to 50 that a traditional washing machine uses.

“You become very conscious of your water use,” Bernadell said.

The rainwater is filtered and run through an ultraviolet purification system before pouring out of faucets, and the couple have found the taste is a bit sweeter than typical tap water. The rainwater also doesn’t leave behind marks in the sinks or tubs, and just a fraction of the typical soap is required for washing dishes or clothes.

Because of their site’s rocky terrain, the cost of installing the rainwater-harvesting system was about the same as drilling a well.

“The important thing is we’re not drawing water from the ground,” Bernadell said.

Green costs

Lower monthly utility costs, longer-lasting materials and improved indoor air quality are some of the major goals of green homes. Zero-energy houses are built to be energy-efficient as well as energy-producing, with solar panels, windmills or rainwater-harvesting systems.

There are exceptions, but in general, the greener the home, the more expensive the cost.

Bernadell said they spent about 25 percent more for their home, but that the costs vary by home depending on the design and the sustainable features. “There is an initial cost and that is a hurdle for the public,” she said.

For instance, they wanted to install solar panels. But ultimately, the cost of the panels was too high compared with the cost of hooking up to the utility line already located next to their property.

When solar panel costs fall in a few years, the couple plans to add them. Williams designed the roof so the change would be an easy one.

“I wanted to be off the grid,” Bernadell said. “It wasn’t cost-effective yet.”

Other added costs come from the materials used inside the home, often for quality flooring, cabinetry, countertops and the like that don’t release volatile organic compounds. The couple avoided using any kind of petroleum-based product.

The home also uses a high-efficiency, environmentally friendly heating and air-conditioning system with cleanable metal ducting. Stainless steel mesh in the foundation controls termites and eliminates the need for toxic chemicals for pest control.

Indoors, long-lasting hardwood floors, tile and Marmoleum flooring were chosen, along with wall paints without volatile organic compounds, Energy Star appliances and low-e argon windows.

“It’s the durability and the indoor air quality that adds cost,” Williams said. “Most homes that are being built are throwaway homes, based on a philosophy adopted in the 1950s. They’re like cars. They’re supposed to come and go.”

But green homes are built to last, and to save a homeowner money over time.

Utility costs are $100 a month.

LEED challenges

Going through the LEED certification wasn’t easy, though

Teresa Fransik of Fredericksburg-based Sierra Homes, the couple’s builder, said a LEED home is more work for the builder, homeowner and architect.

“It was definitely a challenge – a lot of bureaucratic paperwork,” Fransik said. “You had to document everything, prove everything.”

Overall, the biggest lesson the Thompsons learned: “Don’t build a house larger than you need. For every square foot, there’s an exponential cost.”

They tried to keep their home under 2,000 square feet, but ended up with 2,200.

One Response

  1. What the heck! Looking for off-grid homes in Texas and find an article about an off-grid “ready” home that is on the grid? Give me an article about an off-grid home that is “OFF-GRID”!!! Geesh

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