I light a fire every night during the winter to help cut down on my utility costs.  Since I dont have a real fireplace this is the next best thing crackling flames and they do heat the room.  I have found that 2 cans are quite sufficient and last almost 3 hours.  There is a slight odor, but I light 2 scented candles to over come this issue.  I live in a rural area and it is not uncommon to lose power in the winter, when this happens I light both of my fireplaces, 2 cans each, and they keep my house warm winter temperatures here range in the mid 20s to high 40s.