Why Do Gas Fireplaces Have A Blue Flame? (Explained)

If you have a gas fireplace, the flames more than likely burn blue. Most people expect their fires to burn orange, so you may wonder, why do gas fireplaces have a blue flame? 

Gas fireplaces have blue flames because their flames burn at a hotter temperature than traditional yellow and orange flames. Blue flames are safe and indicate that your gas fireplace is working properly. You can change the flame color back to orange by adjusting your fireplace’s airflow. 

This article will explain why gas fireplaces have a blue flame and why blue flames are considered safe. We’ll also go over how you can change your fireplace’s flame color back to traditional orange and other colors your gas-powered flames may be.

Why Do Gas Fireplaces Have A Blue Flame?

Gas fireplaces have blue flames because gas fireplaces burn at a higher temperature than traditional orange and yellow flames. When something burns at 3600 degrees Fahrenheit, the flame turns blue. Blue flames are also an indication that the fireplace is burning with complete combustion. 

Blue flames produced by propane or natural gas burn around 3,600 degrees Fahrenheit, while orange and yellow flames burn less hot at around 2,550 degrees Fahrenheit or less. 

The blue flame color indicates that your fireplace is combusting properly. It’ll look like a blue flame that may have a lighter blue triangle in the center and a small yellow tip. 

So, if you have a gas-powered fireplace, you want to see blue flames as this indicates a healthy fire. 

Now that you know the basics of why gas fireplaces have a blue flame, let’s talk about what the blue flames mean. 

Generally speaking, blue flames indicate that:

  • Your fireplace is generating the right amount of heat
  • Your fireplace is combusting as it should
  • Your fireplace is burning the correct amount of fuel – whether that’s natural gas or liquid propane gas (LPG)

Your Gas Fireplace Is Properly Generating Heat 

One reason why gas fireplaces have blue flames is that they’re generating a much hotter flame. As mentioned earlier, a flame turns blue at around 3600 degrees Fahrenheit, so your flame is burning much hotter than your typical fireplace flame.

It depends on the type of gas (liquid propane gas or natural/methane gas) your gas fireplace uses as fuel what temperature the blue flames will efficiently burn at. 

  • Blue flames from natural gas burn around 3,560 degrees Fahrenheit (1,960 degrees Celsius).
  • Blue flames from propane gas burn around 3,600 degrees Fahrenheit (1,980 degrees Celsius).
  • Yellow and orange flames burn between 1,800 – 2,600 degrees Fahrenheit (982 – 1,426 degrees Celsius)

Your Gas Fireplace Is Correctly Combusting

Blue or darkly-colored flames are another indication that a gas fireplace is combusting properly (aka complete combustion). To produce a flame, combustion must occur between the air and the gas fuel source in a gas fireplace.

If you notice that the flame inside your furnace is a different color than blue, this means you’re likely wasting gas (and your money).

Your Gas Fireplace Is Using The Right Amount Of Fuel

A blue flame inside a gas fireplace also indicates that combustion is occurring inside the fireplace using the least amount of fuel possible. 

Does your fireplace have blue flames? Pat yourself on the back for correctly setting up your gas fireplace! 

If the flames are not blue, keep reading – we’ll go over potential flame colors and what they mean below. 

Is A Blue Flame Safe?

Blue flames are safe because they are an indication that your gas fireplace is properly generating heat, using the correct amount of fuel, and is combusting as intended. 

Therefore, if you see blue or violet-colored flames, your gas fireplace is working as it should be. 

If you see a flame that’s lighter in color (red, green, yellow), this could indicate that your gas fireplace has a problem and is producing less heat. 

It’s actually common to see blue flames, even on all your other household appliances!

Does A Blue Flame Mean Carbon Monoxide?

Because blue flames are an indication that your gas-powered appliance is working properly, blue flames do not mean carbon monoxide is occurring. 

Blue flames minimize your risk of being exposed to harmful carbon monoxide since – again – dark flames indicate a healthy fire via complete combustion. 

What Color Should A Gas Flame Be?

Ideally, a gas fireplace should burn with a blue flame. Blue flames mean that complete combustion is taking place – meaning there is the right amount of gas and oxygen being released from the burner. Other colors could indicate incomplete combustion and a lower temperature of flames, leading to a less efficient fire.

A lighter color, such as yellow, red, or even green, indicates there may be a problem, like incomplete combustion (i.e. you’re wasting fuel). 

Why Is My Gas Flame Not Blue?

The flame in your gas fireplace may not be blue if the fuel to air ratio is incorrect. A yellow flame is often an indicator that the burner does not have enough air to use for complete combustion of the gas, whether that’s liquid propane or natural gas. Non-blue flames can also be a symptom of a dirty burner that needs cleaning.  

You can correct this problem by adjusting your fireplace burner’s air shutter to receive more air or by cleaning the burner. To clean the burner, you’ll have to remove the access cover and vacuum (or spray clean with a can of compressed air) out any soot or deposits. You should also check the ignitor and thermocouple for carbon build-up. 

(To note, it’s recommended to clean your gas fireplace monthly to prevent dust and dirt buildup, even when you don’t use it regularly.)

Can You Adjust The Flame Color On A Gas Fireplace?

Though it depends on the type of fireplace model you have, you can change the flames from blue to traditional orange by changing the airflow to your fireplace.

More specifically, you’ll have to reduce the airflow to change the flame color.

How Do You Adjust The Flame Color On A Gas Fireplace?

You can adjust a fireplace’s flame color by altering the airflow to the appliance. In fact, you’ll need to purposefully reduce the amount of air your fireplace receives in order to change the color from blue to orange. 

How you adjust a fireplace’s flame color depends on what fireplace model you have and how the installer originally pre-set the air shutter. 

However, there is a general way to go about doing this: You will need to gain access to the air shutter, find the set screws that control the air mixture, and adjust them until you reach your desired flame color. 

1. Find The Air Shutter On Your Gas Fireplace

You first need to find the air shutter or air mixture area on the outside of your gas fireplace. 

If your fireplace has glass doors, the adjustable shutters are likely underneath the doors. Have an open-front fireplace? The air shutter is usually located on the gas line that’s feeding the burner.

Once you’ve found the correct place, remove the protective plate that covers the area. You may need to unscrew it. 

2. Find The Valve Screw(s)

Now, you need to locate the valve screw or screws. You should see a valve cover with small holes in it (this controls the amount of air that comes into the fireplace). There should also be a screw or a set of screws that are holding the cover in place. 

3. Loosen The Valve Screw(s)

Loosen the screw (or screws). This will help you move the valve and adjust the amount of air your fireplace is taking in. 

4. Light The Fire

Make sure you do a test run to ensure the flame color is where you want it before sealing your gas fireplace back up. Light a fire, and adjust the valve until you’ve reached your desired flame color (yes, you can adjust it as a fire is burning – though it will also briefly increase the intensity of the flame). 

Remember to put the air shutter panel back on! 

What Flame Colors Can A Gas Fireplace Have?

There are other colors besides blue that the flames in your gas fireplace can appear as. Yellow and orange are typical, but you could also see red, purple, and even green flames. 

Flame colors other than blue or deep violet mean airflow or another potential problem may be lurking, though you can also create these colors yourself using common household ingredients. 

Orange / Yellow / Red 

Unless you intentionally altered the airflow in your gas fireplace to change the flame color from blue (as above), flames that are orange, yellow, and red signify that your fireplace is inefficiently burning (incomplete combustion) and that the temperature is likely not as hot as you’d want it to be. 

While we usually think of fiery reds, oranges, and yellows as colors for intense heat (think the sun), that’s not the case with fireplaces. Blue (or white-blue) is the hottest burning flame color, whereas yellow and red shades represent cooler flaming temps. 


Green flames are a result of copper salts being added to the fire, though it also may result from corroded copper parts and copper ions mixing with the flames, too. Furthermore, pure alcohol makes a pure green fire as well.

While green flames are usually not harmful, they can be a visual reminder to check for contaminants. If you’ve recently cleaned your fireplace and liquid is still on the base or burner intake, the liquid vaporizes as the burner gets hot, and that mixture makes a green flame. You could also see streaks of green. 

Either way, make sure you are properly cleaning your fireplace between uses. 


Purple flames are made from gas and burning metal, like metal salts like rubidium and potassium.  

For reference:

Flame Colors And The Approximate Temperatures They Burn At

Red glow 935 degrees Fahrenheit501 degrees Celsius 
Red flames 1,115 – 1,835 degrees Fahrenheit 601 – 1,001 degrees Celsius
Orange flames 1,835 – 2,195 degrees Fahrenheit 1,001 – 1,201 degrees Celsius 
Green flames2,000 degrees Fahrenheit 1,093 degrees Celsius 
Yellow flames 2,195 – 2,552 degrees Fahrenheit1,201 – 1400 degrees Celsius

Dan Westfield

Hi everyone! My name is Dan and I currently have two fireplaces, a wood-burning and a gas one. I cannot live without them and love to share my passion with you all!

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