Christmas lights are a funny thing. Many people hang lights on the outside their homes during the holiday season. The light displays run the gambit from small affairs around a door to enormous light extravaganzas on every surface, tree, and shrub. The quality of a display varies greatly depending on the skill and effort exerted by the homeowner. It is curious though–Since the lights are on the outside of the house where the owner cannot see them, why do they exist?
To begin, I list (some) benefits of Christmas lights. One, to be fair, the owner does see the lights for a brief moment when she comes home at night, providing an aesthetic joy. Two, a religious homeowner can be use a holiday light display to advertise her beliefs. Three, passer-bys and neighbors receive the enjoyment of looking at the display (if it is well done, of course)! This last benefit is a classic positive externality, where non-displayers receive benefits without incurring the cost directly.
Next, I list (some) costs of Christmas lights. One, the displayer holiday lighting increases their electricity bill compare to normal electricity usage. For large displays the electricity cost can be quite high, and I have seen houses that never turn off their Christmas lights from Thanksgiving until Easter! Two, the extra electricity usage requires more production from power plants that likely burn coal, leading more air pollution and greenhouse gases. Three, excess lighting creates a phenomenon called “light pollution” that impedes car driver sight-line at night, disturbs nocturnal animals, and blots out the stars. These last two items are negative externalities.
On net, it is hard to say if Christmas lights are “worth it” for the displayer. It is even harder to determine if they are a net benefit for society when the externalities are added-up. Regardless, Christmas lights are an ingrained tradition in America, and will be around for foreseeable and likely distant future. Hopefully with increasing awareness about the costs of holiday lights, people will consider lower impact decorations such as low-wattage bulbs, or putting existing lights on timers so that they turn off over night. Happy holidays and joyous New Year!