Sure, the word "green" doesn't exactly leave you trembling in excitement. Perhaps that's because you haven't been talking to the right people. For anyone considering building an office or just a renovation, we explore four ways to go eco-friendly, each a little more permanent than remembering to unplug the office copier.

1. Meet Legos's Big Brother.

An insulated-concrete form is a long hollow box made of durable plastic, and it works sort of like a giant Lego block. They’re stacked together and then filled with concrete and steel frames.  At the end, the bricks form a super-airtight wall, says Ryan Thewes, an architect based in Nashville, who specializes in green construction.

To test a new wall, Thewes will bring in fans, switch them on, and let the air circulate. He also sets up monitoring equipment to find air leaks. Of course, with ICFs, there aren't likely to be any.

"Theoretically, in some of these buildings, you could heat with a hair dryer," he says. "It's going to be pretty interesting to see what the energy bills are going to be, since this will trap the heat better. And I have seen offices built with this same kind of philosophy."

2. Think Big Roofs and Grand Windows.

A roof that protrudes over a structure can mean a lot for the occupants, Thewes says. The larger the overhang, the greater the shade. When winter comes, having a southwest exposure will make sure the sun hits the windows, causing the place to heat up naturally and reducing heating costs.

As for windows, you should opt for ones as grand as that roof. The bigger the window, the less artificial light you need, driving down electricity costs. Plus, bathing the place in natural light will give the place a comfortable, natural feel. "People tend to work better and be happier with more natural light," Thewes says. And while it's almost an industry standard now, you should make sure you buy UV-coded windows, which allows light in, but helps block heat-producing wavelengths.

3. Before Buying, Salvage What You Can.

Brand-new building materials can cost a small fortune. Plus, all that transportation and the materials' manufacturing carry a hefty eco-print. First, you should look at what's around to salvage, says David Montalba, founder of Montalba Architects. When Montalba's firm handled the design of Washington Square Park Dental in San Francisco, he knew the office needed new dental chairs. New ones were too expensive. So Montalba found some discarded ones from the 70s, had them refurbished, and installed.

"We were like, man these are better than any chairs we could buy," he says. "But the first reaction is to go and buy a new chair."

Better than new? Yes, and eye-catching, earning Montalba a finalist spot in our World's Coolest Offices content.

4. Become a Locavore.

To cut down on transportation costs and further eco-damage, you should investigate locally produced materials and nearby leftovers, says Heather Gayle Holdridge, sustainability coordinator at architecture firm Lake Flato. When Lake Flato was working on building Shangri La Botanical Gardens in Orange, Texas, several hurricanes struck the area. Never one to pass up opportunity, the designers used paving flagstone that came loose during the storms as a building material.

Of course, availability differs by region. In Texas, where Lake Flato is based, concrete comes cheap thanks to the plentiful quarries. So does limestone. "But we have a little more trouble with wood," she says. So Lake Flato often turns to old farms. Barn-wood adds texture, vintage, and a touch of the outdoors. And plenty of owners are looking to get rid of old barn-wood.

Most designers and architects can point you in the direction of locally sourced materials. For the DIY crowd, there are websites like Building Green, which catalogs eco-friendly materials.