We study the short and long-term eects of information provision on ecient lighting through an online eld experiment in China. Providing information on monetary and environmental benets of LED light bulbs causes an immediate increase in willingness-to-pay (WTP). This eect decays hyperbolically over time: WTP decreases by half after three months, and only 20 percent of the initial impact is left after ten months. However, when information provision leads to knowledge acquisition, WTP for ecient light bulbs doesn’t drop over time. Monetary and environmental information have similar impacts, though environmental information is less eective if outdoor air pollution is high.