Halogen lamps became increasingly popular through the ’90s. Their high-wattage bulbs gave off a clear, pleasant light and — at $15 to $25 — even a student could afford them. Unfortunately, the lamps also gobbled electricity and their bulbs burned hot enough to be blamed for several fires and two fatalities. As part of her senior thesis, Harvard College undergraduate Linsey Marr, Class of 1996, designed an energy-saving floor lamp to replace the hot-burning halogen torchiere lamps. Now a lamp based on Marr’s design is being used at Harvard and sold commercially by Energy Federation Inc., which produced a commercially viable version of the lamp. In the fall of 1998, 620 of Marr’s lamps, which use fluorescent instead of halogen bulbs, were distributed in Harvard freshman dormitories as part of a multi-year plan to put one in each student room on campus.