Alex Williams and Nealie McBean want to build an energy efficient home in Superior Township, and that's why they spent the morning at the Mission Zero Fest in Ann Arbor.

"This festival is a great resource about what's available," said Williams. "We want to build a LEED certified house with geothermal heating and cooling." Williams was referring to the Leadership in Energy & Environmental Design green building certification system.

"We want a green roof and solar cells," McBean said.

The festival is taking place this weekend in the Water Hill neighborhood of Northwest Ann Arbor, centered in the 700 block of Fountain Street. Dozens of exhibitors are on hand showing examples of green building and sustainable living.

Visitors can attend free workshops both Saturday and Sunday. Saturday, Matt Grocoff, one of the event's organizers, talked about his net-zero house (one that produces at least as much energy as it uses.)

"It's not about perfection but about performance," he told the audience.

At the Architectural Resources booth, visitors learned about the cost savings of repurposed materials. Srimivas Julakanti of Canton said he wants to make his home more efficient."

Joe Palms and Sara Vogler walked to Fountain Street from their home, just a block away, to take advantage of all the available information.

"I'm curious about how to maintain a lawn without having to mow it," said Palms, who was hoping to attend a workshop on the subject.

There are also six energy efficient homes in the Water Hill neighborhood open for tours this weekend. Bob Simons and Susan Theut own one of those homes, which is located at 215 West Summit Street.

"This is a great way for people to see how improving energy efficiency can be done," said Simons. "Meadowlark Building started a year ago on what was a totally gutted house, and put in new electrical, plumbing, heating and cooling. To me it's like a new house."

Lisa Rousseau, who works for Meadowlark Builders, brought her daughters to the Mission Zero Fest to help set up.

"It's important to educate people about how easy some of these things are to do," said Rousseau.

Her daughter Rebecca Rousseau is a graduate student in energy systems engineering at the University of Michigan. "I'm here because I want to make a difference," she said. "This is all about educating people about what we can do to be more green."

The Mission Zero Fest runs until 6 p.m. Saturday and from 11 a.m.-4 p.m. Sunday and also includes music and food stands. Admission is free. For more information, go to the organization's website.