Home » Cost To Run A Gas Fireplace: How Cheap Is It

Cost To Run A Gas Fireplace: How Cheap Is It

Winter’s chill is here once more and it is now time to kick up the heat to keep your house warm and cozy.  There’s nothing quite like a toasty fire to bring warmth to a home and I’m sure there are plenty of you enjoying a gas fireplace.  But before you flip that switch to start it up, ask yourself this question.  Do you know what running your gas fireplace is costing you?

Whether you run the fireplace for ambiance or warmth, it’s alway a good idea to see if you’re getting enough heat for your money or if your money is just going up in smoke.  

Not to mention, just about everyone I know who has a gas fireplace claims it saves them money on their heating bill compared to a central forced air gas furnace.  But is that really the truth?  Well, here’s the concise answer.  

Running a gas fireplace costs $0.20 – $0.40 per hour while a standard gas furnace averages $0.95 per hour.  However, an efficient furnace will convert 95% of the natural gas energy into usable heat, compared to 60% efficiency for gas fireplaces.  That means your gas fireplace would need to run 5 times longer than your furnace to produce the same amount of heating power.

Of course the full answer is never that simple.  There are many more variables that can change the answer.  Your climate, gas fireplace model, the efficiency of your furnace and insulation all factor into the calculation. 

Keep reading to find out if your gas fireplace is the best source of heat for the money.

How much does it cost to run a gas fireplace

The actual cost of running a gas fireplace depends on two primary factors.  The first being the BTU output of the fireplace and the second being the cost of your natural gas.  

When it comes to fire, energy output is measured in British Thermal Units or BTU.  Most gas fireplaces burn through 20,000 to 40,000 BTU/hour of natural gas depending on the make and model.  There are also gas fireplaces that have adjustable burn rates.  For the sake of this article, we’ll assume a constant output.  On average, most gas fireplaces, vented or un-vented, burn through 30,000 BTU of natural gas in one hour.

To start calculating actual costs, we also need to know natural gas prices.

Right now, the national average cost for natural gas is about $1.06 per Therm.  One Therm equals 100,000 BTU.  

With those two pieces of information, we can start calculating the average cost to burn a gas fireplace for different durations.

Per hour

The average cost for you to run a 30,000 BTU gas fireplace is $0.32 per hour,  assuming that your natural gas costs around $1.06 per Therm, which again is the national average at this time.  

Per day

Running an average gas fireplace for one whole day (24 hours) will cost approximately $7.68.  If instead you run your gas fireplace for about 8 hours during the day, it will cost you $2.56 per day

Per week

It’s unlikely you will run a gas fire for a full week, 24 hours a day.  So, let’s assume you run it 8 hours a day for a full week instead.  That’s 56 hours over the span of a week at $0.32 per hour.  If you burn your gas fireplace that much, expect to pay $17.92 per week for natural gas.

Per month

Similar to our per week calculation, let’s again assume you don’t run your gas fireplace more than 8 hours each day.  So, in a 30 day period you’ll burn up 240 hours.  At $0.32 per hour of natural gas, it ends up costing you $76.80 for the month.

Calculating the cost to run your gas fireplace

The costs listed above are for the average gas fireplace at an average cost for natural gas.  Obviously, there are dozens of different fireplaces and the cost of natural gas varies across the country and from one time of year to the next.

For those of you who appreciate more precise calculations tailored to your particular scenario, there is a super easy way to calculate the exact cost to run your gas fireplace. 

To find out, start by looking up the BTU input for your particular gas fireplace.  You’ll find this information in the owner’s manual or online by looking up the make and model number.  Sometimes the BTU input is given as a range, in which case the actual gas consumption depends on the input flow of your gas line.  

Generally though, you can assume your fireplace is burning at the maximum input.

The next step in calculating the cost is to consult your energy bill.  Your natural gas provider likely breaks down your gas costs by price per Therm.  That is the number you want.  In some cases, gas providers may further break down the costs into separate delivery costs and gas cost for each Therm.  If so, make sure to add those two values together.

Once you have that information, the rest is simple and only requires some fast, easy math to figure out your actual costs.  The following formula is all you need to calculate the cost of running your gas fireplace for one hour.

As an example, my gas fireplace has a max input of 19,100 BTU.  My gas costs $0.49 per Therm with a $0.48 delivery charge per Therm.  That’s $0.97 per Therm or 100,000 BTU of natural gas which is slightly below the national average.

The calculation looks like this:

Which equals about $0.19 per hour of operation.

I encourage you to figure out the cost of running your fireplace too.  Finding out it won’t cost you an arm and a leg to enjoy a cozy fire every once in awhile is totally worth it.

Can you heat a home with a gas fireplace

As wonderful as a gas fireplace is at making a room feel comfortably warm, they do have their limits.

Unfortunately, a gas fireplace is not very effective for heating the average home.  Even with a blower fan, it is very difficult to circulate heat from the fire efficiently throughout your house.  Most gas fireplaces can effectively heat 500 square feet or less.

Unlike a forced air furnace with ducting that reaches every room, attaining even heating with a gas fire is impractical.  For that reason, gas fireplaces are best used for heating the room where they are located. 

You can get more heating power if using a fireplace equipped with a blower fan.  Plus, with strategically placed ceiling fans, you can circulate heat to adjacent rooms.  Just don’t set your expectations too high.  Gas fireplaces are meant to warm one room not the whole house. 

Can you run a gas fireplace all day

A common question I get asked is whether or not a gas fireplace is safe to run all day.  

Gas fireplaces produce virtually no smoke or creosote build-up.  However, the most dangerous by-product of natural gas combustion is carbon monoxide.  It is an odorless, tasteless gas capable of silently killing unwary victims.  

Vented gas fireplaces exhaust the CO gas out of the house while burning which makes them relatively safe in the home.  Ventless gas inserts, on the other hand, increase the risk of CO poisoning in your home.  Modern ventless gas inserts have catalytic converters similar to your car that scrub CO from the exhaust gas before it enters your home.  Plus, they now come standard with safety shut-off switches that trip when dangerous levels of CO are detected.

Even so, both ventless and vented stoves can have faults that leave you and your loved ones vulnerable to carbon monoxide poisoning.  For that reason, it is never a good idea to run any gas fireplace all day.  Especially, while you are sleeping or away from your home.  

Is a gas fireplace cheaper to run than a gas furnace

This is a tough one.  Comparing the cost of running a gas fireplace to the cost of running a gas furnace requires a little more math and a lot more assumptions.  But alas, it can be done.  

In a basic sense, comparing the costs requires an understanding of the efficiency of a gas fireplace versus a gas furnace and the total BTU output of each.  Plus, we need to think about the amount of energy needed to heat an average home.  Follow along and let’s find out together.

Gas furnaces consume quite a bit more gas.  It varies from home to home but the average usage for a standard gas furnace is 100,000 BTU (1 Therm) per hour.  Using the national average cost of natural gas, it costs $1.06 per hour to run the furnace.  

Here’s the catch though.  A modern furnace is nearly 95% efficient at turning the energy from gas into usable heat.  Therefore, 100,000 BTU of gas input is converted into 95,000 BTU of heating power.  

A typical vented gas fireplace, on the other hand, averages 60% efficiency.  Although, some ventless inserts obtain higher efficiency but for the sake of discussion, let’s assume the more likely scenario of heating with a vented gas fireplace.  

A gas fireplace with 60% efficiency converts a 30,000 BTU input into 18,000 BTU of heating power at a cost of $0.32 per hour.  

In order for your gas fireplace to produce 95,000 BTU of heat, it would need to run for over 5 hours at a cost of $1.69 compared to the $1.06 cost of running the furnace.

Taking it one step further, a 2,000 square foot home located in an average US climate needs about 90,000 BTU of heat to maintain a comfortable 70°F temperature.  Using our gas furnace from the previous example, it would take roughly one hour to efficiently heat the home at a cost of $1.00.  The gas fireplace would need to run for 5 hours at a cost of $1.60.  And that is assuming you can effectively disperse the heat generated from the fireplace around your home.

As you can see, a gas fireplace is not cheaper than a central forced air gas furnace for heating your home.  

How to save money with a gas fireplace

It’s nice to know that the cost of running a gas fireplace won’t break the bank but it’s  not cheaper than a gas furnace for heating a home.  However, that does not mean you can’t save some money by strategically using your gas fireplace.

Conveniently, homes are design with gas fireplaces located in living spaces where you spend most of your time.  Save a little money by running your gas fireplace while you are enjoying that space and simultaneously turn down the thermostat for your furnace.  

More than likely, you don’t spend a great deal of time in your bedroom until it is time for bed.  So why use the furnace to pump heat into an unoccupied space?  

You can save a significant amount of money by keeping your thermostat set lower during the day while running your gas fireplace in the area of your home where you spend most of your time.