Gas lamps harken back to the romantic elegance of a bygone era. The industrial period was dirty and full of social hardships, but it witnessed the rise of many mechanical wonders. Gas lamps lighted up the homes and cities of those times, creating new precedents for the way people used lighting in their lives. Today electrical light dominates, but gas lamps survive on the fringe. The machine-stamped patterns of modern lampposts recall the artistry of old, and gaslight itself gives a warm and pleasant flame that livens up the dark hours.
Hours of Operation
A gas lamp's operating cost depends on how much fuel it consumes, how much money that fuel costs, and how often you run the lamp. Some gas lamps run all the time. If you run yours only when it is dark enough for the flame to be useful, you will cut your expenses by more than half. You can achieve even more savings by not running the lamp all night long, or by only running it some nights.
Gas Usage
Your lamp should have a plate or label indicating how much energy it uses, in BTUs per hour. You can also call the manufacturer to get this information. Modern yard and driveway gas lamps typically use between 1,000 and 10,000 BTUs per hour, based on continuous operation. Indoor lamps typically use a little less. However, with such a wide variety of designs available, you may find models that exceed these ranges.
Gas Prices
Gas prices make up the other half of the cost equation. Modern gas lamps usually run on natural gas supplied by your local gas utility. Natural gas is a widely occurring hydrocarbon or "fossil" fuel, extracted and refined into nearly pure methane before being delivered via utility pipelines to consumers' homes. You can find out the gas prices from your local natural gas utility simply by calling them or visiting their website. Gas utilities usually price natural gas by the therm, which is equal to 100,000 BTUs.
Typical Figures
Between the amount of fuel they use and the price of that fuel, gas lamps cost more to operate than comparable electric lights. However, they do not cost so much more as to make them impractical. At a typical price of 60 cents per therm, a typical outdoor gas lamp using 3,500 BTUs per hour would consume about 300 therms in a year, working out to an annual cost of $180, assuming continuous operation. By limiting your lamp use, you could operate it for much less.