A virtual family in Gaithersburg, Maryland, is helping scientists at the National Institute of Standards and Technology (NIST) demonstrate that an ordinary-looking home can more than offset its energy usage.
The home generated a surplus 491 kilowatt hours of energy in its first year of operation, according to a report on the agency’s Net-Zero Energy Residential Test Facility released earlier this month. That savings, which exceeded expectations, amounts to more than half of what the average American household uses in a month.
There are other net-zero projects around the country, says A. Hunter Fanney, chief of NIST’s Energy and Environment Division, but NIST’s house is unique in achieving net-zero energy consumption without skimping on the comforts of a regular home. The home touts a long list of energy-saving technologies and design features, from geothermal heat pumps to smart energy zones that concentrate power only where it’s needed. With the exception of the five solar panels on the roof—a large one which converts solar power into electricity and four smaller panels that convert solar into heat energy—the home looks indistinguishable from what you might find in any comfortable neighborhood in the Gaithersburg area.
“It was important to us that the house looked appealing,” Fanney said. “We’d like to see the general public move towards net-zero energy homes, and we think the way to do that is to show people they can have a house similar to what they’ve always had and yet still have a net-zero energy bill.”
The house may have decent curb appeal, but its extra cost is nothing to scoff at. “The cost difference between a regular home and this one is about $160,000,” Fanney said. Fanney estimates it would take the virtual family 28 years to earn back the extra cost of their zero-energy home through energy savings alone.
That’s a daunting prospect for those in the market for a net-zero home. David Roberts, a senior engineer at the Department of Energy’s National Renewable Energy Laboratory in Golden, Colorado, believes the average homeowner looking for significant savings on their energy bill would do better by reducing the home’s energy requirements instead of producing energy in-house.
The most cost-effective way, he says, is to increase insulation in the walls and roof of a home and to reduce air leakage. Going a step further by implementing energy-efficient appliances will cost a bit more.
“A house can get pretty close to net-zero with better insulation and appliances alone,” Fanney says. But it’s the renewable energy solutions—the last bastions to net-zero—that take the biggest bite out of your wallet.
NIST’s Net-Zero facility cost $2.5 million to build, with much of the expense going to the equipment and monitoring devices needed to make the house a functional laboratory. But price was not a key factor in the experiment, Fanney says. “One of the purposes of the house’s first year is to demonstrate that net-zero is even possible for an ordinary-looking home, and we’ve shown that.”
With the initial success under its belt, NIST plans to turn the home into a testbed to develop performance metrics for companies who manufacture energy-efficient appliances. The energy ratings on current appliances are based on ideal laboratory conditions, Fanney says, far removed from the reality of how an appliance functions in a real house. NIST aims to take technologies from energy-efficient appliances and test them in the more realistic environment of the Net-Zero home.
Homeowners looking for a cost-effective way to lower their energy bill can look to more energy-efficient systems. But Fanney thinks the future lies in full net-zero energy consumption. “It’s good to demonstrate efficiency, but I think net-zero should be the ultimate goal,” he says.