You don't need a flat-topped industrial building to enjoy the benefits of a cooler, more efficient roof and extra garden space. Kevin checks out a new way to install a "green roof"-one covered with thirsty, low-maintenance plants that suck down storm water, prevent heat sinks and insulate the building below. Next, Amy shows how to cut your hot water bills in half with a hybrid heat pump water heater. Then, Kevin's got the latest in LED light bulbs to slash your lighting bills in half, including a web-enabled meter that'll show you if your savings are adding up. And finally, Amy's in Berkeley, California, because the "granny shack" is back. In the tradition of "in-law" or "poutin' shacks," these backyard cottages are super small and super efficient and can be built for under $100K by piggybacking onto existing homes' infrastructure. For homeowners looking for more space or extra income, and for renters in search of a decent deal, this new revival is a win-win.