At first glance, the two modular homes on the south end of the Energy Department’s Pacific Northwest National Laboratory (PNNL) campus in Richland, Washington, look like traditional family homes. But on closer inspection, visitors can see they are part of a project to change how Americans use and save energy at home.

Called the PNNL Lab Homes, the two houses serve as a test bed for energy-efficient products, helping a team of PNNL researchers evaluate how new building technologies work and calculate their energy savings for the typical American family.

Even though the two homes look identical, there are slight differences. Researchers test new technologies in the Experimental home, while the Baseline home serves as a control and doesn’t get changed during any of the experiments.

To ensure they could accurately compare energy data, researchers installed 42-circuit commercial lighting panels with half controllable breakers to monitor and control individual energy loads in the homes. They also performed extensive baseline testing to make sure the energy use between the homes is identical before beginning the project, and the same testing is repeated in between every experiment.

The first experiment looked at triple-paned windows with low-emissity (low-e) coating and a special gas fill to limit heat loss — what industry calls highly insulating windows. While the windows performed extremely well in Lab Home, saving 12.2 percent on whole-house energy use, their current price makes their payback period anywhere from 28 to 55 years. That led the team to look at the efficiency and cost-effectiveness of low-e storm windows, and they hope to release the findings in March 2014.

One thing that makes these houses so effective at evaluating technologies is that no one actually lives in them. Incandescent light bulbs and wall heaters were added to replicate the heat given off by a person’s body and home appliances, and researchers automatically control lighting, water heating systems, and heating and cooling equipment to simulate the typical energy use of a family of three based on data collected from the Department’s Building America program.

“One of the things that confounds results when you try to evaluate a piece of energy efficiency technology is that a homeowner might not always do the exact same thing one day to the next or one month to the next,” says Sarah Widder, one of the Lab Homes researchers. “We take away the confounding influence of behavior when we simulate occupancy identically.”

Because the researchers understand the homes so well and control all the energy use, they don’t need to collect data for an entire year. They can typically assess a technology’s energy use by studying it for about a month during the heating season and a month during the cooling season. Researchers evaluate the data they collect and then fit it to different energy models to apply the findings to other climates or building types.

Current experiments in progress include looking at the performance of a heat pump water heater and evaluating a type of smart grid software’s ability to coordinate electric vehicle charging, smart appliances and water heaters. In the future, Widder hopes to expand the smart grid experiment by adding solar panels and energy storage to the house. Researchers will then be able to evaluate how the smart grid software can help optimize the Lab Homes’ energy use by maximizing the use of solar energy from the home’s solar panels and minimizing the size of back-up energy storage.

But future experiments aren’t just limited to Widder’s ideas. Anyone can provide suggestions for what technologies the researchers should test next. Widder says that since the Lab Homes project began in 2011, they have received dozens of suggestions from a wide variety of people including the general public, building technology manufacturers, other researchers and utility companies.

“In order to be doing the most important research in the Lab Homes, we need to be answering the questions that are at the forefront in people’s minds,” Widder said.

Learn more about the National Labs and their work to help consumers and businesses save energy and money.