This house looks ordinary, but it boasts a superpower: its solar panels produce all the energy the homeowners use.

Innovative lighting, rain gardens, mini-split heat pumps, electric vehicles, and high-tech appliances—what do these have to do with solar panels? They will all be featured at homes and businesses opening their doors to the public on Saturday and Sunday, October 6 and 7, as part of the National Solar Tour.

You can find open houses and tours near you using this map or the listing on this site. For those in Northern Virginia, a downloadable booklet describes more than 40 solar and green homes participating in the Metro DC tour. The website also tells you where you can buy a hard copy if you prefer. Some homes didn’t make it into the booklet, which went to press over the summer.

The American Solar Energy Society (ASES) started the National tour more than two decades ago, but the Washington metro area tour is now in its 28^thyear. This is pretty astonishing if you think about where solar technology was in 1990.

As a “tourist” during the early days, I remember the gee-whiz feeling I got exploring the handiwork of early solar adopters. It is the tragedy of my life that I live in the woods and can’t have my own solar panels. Fortunately, the tours have always been about more than just generating electricity. Back then, they had to be, because not many people could afford solar PV. Good design and energy efficiency took center stage.

Through the tours I learned about passive solar houses, solar hot water, insulation made from old blue jeans, natural light via “daylighting,” the incorporation of recycled materials into beautiful tile and countertops, eco-friendly siding materials, and how to live with nature using native plants and rain gardens. More recently the tours have branched out to include electric vehicles and green roofs.

This year’s Metro DC tour booklet includes new homes built to Passive House standards and loaded with cool features, but to my mind the more interesting entries are ordinary homes that have undergone a thoughtful retrofit. Here is a description of one of the latter:

This 1950s ranch house has solar PV, solar hot water, solar space heating, a cupola/solar chimney, solar daylight tubes, solar attic fan, solar sidewalk lights, south facing energy efficient windows, 2 highly efficient energy star minisplit heat pumps (26-SEER), a fireplace insert wood stove, exterior insulation finishing system (EIFS), CFL/LED lighting, kitchen counter tops made from recycled glass, and recycled floor tiles in the foyer and basement. The yard has a 1000-gallon cistern, food forest, 2 rain gardens, permeable walkways, 2 rain barrels, and 2 compost piles. There is also an aquaponics system, a Chevy Volt and a plug-in Prius. Installation by Greenspring Energy.

These renovations suggest an important point: reducing energy use doesn’t require us to tear down our homes and start over. And thank heavens for that, since most of us aren’t going to do that anyway.

Besides which, existing homes make up so much of our housing stock that making big efficiency gains depends on how well we retrofit and weatherize old homes. So if a house built in the 50s can be turned into a solar energy showcase, the rest of us should be taking notes.