A gas fireplace is considered to be one of the relatively inexpensive fuel types. The exact cost of running a gas fireplace will depend on two factors- the current price of fuel, and the output of the unit, which is measured in BTUs. Also, you need to consider whether the unit is used for decoration or as a heating source.
There are two subtypes of gas fireplaces, which are: propane and natural gas. If you’re opting for natural gas, it will cost you around three times less than propane.
It’s impossible to give an accurate rate card of the entire cost since the price of gas tends to fluctuate over time, and it also varies from region to region.
For an estimate, an hour of operation of a 40,000BTU unit will cost you around 50 to 60 cents. You can use this for heating approximately 1200 to 1500 square feet living area.