On Earth Day 2013, Ann Taylor parent company Ann Inc. (UNKNOWN:ANN.DL) announced that across nearly 400 stores in North America, it had cut its "carbon footprint" by 20% -- twice its objective, and more than two years ahead of schedule.

But this company's not only doing its part to save the Earth -- it's also saving money on energy costs, boosting earnings and and helping to create for itself a very attractive P/E multiple. Fool contributor Rich Smith explains how Ann Inc. is doing well by doing good -- and could be good for your portfolio.