How Much Gas and Propane Does a Gas Fireplace Use?

A gas fireplace uses 22 to 75 cubic feet of natural gas per hour based on fireplace capacity from 15,000 to 50,000 BTUs. A propane fireplace burns .25 to .85 cubic feet per hour in the same size range.

See the gas use charts below for both natural gas and propane fireplaces. They show how much gas a gas fireplace uses based on their output capacity.

How Much Gas Does a Gas Fireplace Use?

Natural gas is measured in cubic feet – it is a gas, of course, unlike propane which is stored as a liquid.

Natural gas is the most common fuel used in gas fireplaces. It enters homes through piping from infrastructure running along the streets in most cities and suburban communities.

Natural gas is not available in most rural areas – and it is less common in the Northeastern United States.

How Much Gas Does a Gas Fireplace Use?

Heat OutputGas Usage Per Hour
15000 Btu22 cubic feet
20000 Btu30 cubic feet
26000 Btu38 cubic feet
27500 Btu40 cubic feet
30000 Btu45 cubic feet
32000 Btu48 cubic feet
50000 Btu75 cubic feet

* Natural Gas Efficiency: 65%

The chart shows the amount of natural gas burned per hour.

How much natural gas does a fireplace use per month?

Of course, it all depends on how much you use your fireplace – and the output capacity of the fireplace.

1 hour per day = 660 to 2,250 cubic feet per month based on the size of the fireplace.

3 hours per day = 1,980 to 6,750 cubic feet per month based on fireplace capacity.

A 30000 BTU fireplace is a popular size. It burns 45 cubic feet per hour and around 1,350 cubic feet per month when it is used 1 hour per day.

How Much Propane Does a Fireplace Use?

Propane is more accurately called liquid propane or LP gas. Because it is a liquid, it is denser than a gas in its stored form. That’s why when a natural gas fireplace burns 75 cubic feet of natural gas per hour, a propane fireplace burns .85 cubic feet of propane per hour.

The liquid propane is converted to a gas when it passes through the valve in your fireplace.

How Much Propane Does a Fireplace Use?

Heat OutputPropane Usage Per Hour
15000 Btu0.25 cubic feet
20000 Btu0.35 cubic feet
26000 Btu0.45 cubic feet
27500 Btu0.45 cubic feet
30000 Btu0.50 cubic feet
32000 Btu0.55 cubic feet
50000 Btu0.85 cubic feet

Propane is most commonly used in rural areas. Liquid propane is contained in tanks onsite rather than pumped through an underground infrastructure of pipes. It is delivered by truck and pumped into the tank – popular residential tank sizes range from 250 to 1000 gallons.

Do you have a tank in your yard? Then you probably have propane.

How many hours can you run a gas fireplace?

Experts are divided on the answer to this gas fireplace FAQ. And that’s mainly because each fireplace model has unique specifications.

Some believe that it is OK to run a fireplace non-stop while others suggest running the unit for a maximum of 3-4 hours per day. Another common answer is to be sure to turn it off at night, when nobody is monitoring the fireplace.

  • Fireplace inserts in an existing masonry fireplace can usually be run continuously.
  • Direct vent fireplaces vent through a wall to rid the fireplace of dangerous combustion gasses. Most of these units can also be run continuously.
  • Vent-free fireplaces burn propane or natural gas so efficiently that venting isn’t required. However, most fireplace pros recommend that you run a vent-free fireplace for just a few hours at a time.

The best advice about how long a gas fireplace should run is to consult the owner’s manual. If you don’t have one, check for it online or contact the manufacturer.

Is it cheaper to run a gas fireplace or the furnace?

In most cases, it is cheaper to run the fireplace. This is because gas fireplaces burn less fuel than most gas furnaces.

In the charts above, the fireplace units range from 15,000 to 50,000 BTUs.

Gas furnace sizes start at about 40,000 BTU output and can be as large as 120,000 BTUs. However, gas furnaces are generally more efficient than fireplaces. For example, gas furnace efficiency ranges from 80% to 99% while natural gas fireplaces are around 65% efficient. More of the heat created by burning fuel is lost out the vent when using a fireplace.

To save money when using the fireplace for heat, consider turning down the thermostat for the central furnace by about 5 degrees – especially if everyone in the home at the time is gathered near the fireplace.

Written by

Rene has worked 10 years in the HVAC field and now is the Senior Comfort Specialist for PICKHVAC. He holds an HVAC associate degree and EPA & R-410A Certifications. Protection Status