In the pre-crash days, sustainable building materials and low-flow toilets became part of the common real estate conversation: Slap "eco" on a home, the thinking went, and it was more valuable, not just to the earth but to the homeowner.

The most direct path to an officially green building was through third-party certification—if the building could check enough boxes on a list, it was green. LEED, which stands for Leadership in Energy and Environmental Design, is the most prevalent. The checklist includes boxes for everything from air purifiers to locally sourced lumber to low-emission paint.

You’d think that in this era, when the top tier of the luxury market is starting to wobble—and LEED has been lampooned for putting bicycle storage on par with geothermal heating—that third-party certification wouldn’t hold much water. But green still commands a higher price—at least, if the builder or homeowner gets the formula right.

The team at combed through their inventory of active single-family homes over $750,000 and found that individual eco-friendly features such as low-voltage lighting or solar panels result in only a slight uptick in price. Homes with Energy Star appliances command a median 8 percent premium over similar homes that lack them. So do smart thermostats. (Premium calculated the percentage difference as the difference between the median price per square foot of homes with an eco feature and that of all other homes in the same zip code.) Solar panels can knock the price up 12 percent. Bamboo floors and dual pane windows, however, don’t seem to affect the price at all.

But homes with the whole eco kit and caboodle can cost much more. The median premium for LEED homes is a whopping 50 percent. It turns out you’ll need a lot more green to get a green home.

“Affluent buyers do not want eco at the expense of luxury, but if you can put them together, they’ll pay a premium,” said Gregg Lynn, Realtor with Sotheby’s International Realty, who has sold several luxury green homes in San Francisco. The homes he sells are like Teslas: His clients buy them as much for design as for their environmental attributes, he said. They wouldn’t buy a Prius or the real estate equivalent of one.

Neither should you. Here are seven super-green homes across the U.S. that are asking a pretty penny, too.

4443 19th Street — San Francisco

This custom LEED Platinum townhome in San Francisco's Castro District was designed and built for a tech company exec, so it makes sense that it would include green widgets. The most dramatic of these is a wall made of industrial polycarbonate panels that bump up energy efficiency: They both filter heat and let natural light through. This home has no electric bills. It generates all the electricity it needs though photovoltaic panels.

The location gets a green thumbs up, too, with a Walk Score of 94 (another third-party rating, which reveals the walkability of a location) and a Transit Score of 90. The three-bed, three bath, 1,647-square-foot home, designed by DNM Architects, includes a guest house, a two-car garage (hope it's a Tesla), a laundry room, and an outdoor rooftop living room with a fireplace and killer views. Asking price: $3,750,000

1021 McCormick Ranch Rd. — Crested Butte, Colo.
You can build your own eco-haven on McCormick Ranch’s seven 35-acre lots. But for a turnkey option, there’s already one finished property that includes a guesthouse and barn, with a finished space above the garage. That adds up to two bedrooms, three bathrooms, and 2,221 square feet of living space.