The Orvis Outlet Store, a globally-known retailer of outdoor lifestyle products, has become a showcase for one of Efficiency Vermont's latest energy-conservation experiments: LED lamps for retail stores. Orvis personnel replaced about 300 lamps in the outlet store last summer. According to the company, the store has used 8,400 fewer kilowatt hours a month, which has saved almost $900 a month in electricity. The LED lights are cooler than incandescent lights so the store also saved on air-conditioning costs.