Why Gas Fireplaces Have a Blue Flame (& Can It Be Changed)?

Many of us are used to seeing yellow and orange fires in campfires and traditional fireplaces. Seeing different colors of flames may give us pause, like the blue flames that come out of gas fireplaces. So why are the gas flames blue?

Gas fireplaces have a blue flame because it’s the color that propane and natural gas flames naturally emit when burned. On the other hand, wood fires burn yellow, orange, and red due to the carbon found in the wood. Because gas fires have more oxygen and complete combustion, their flames are usually hotter.

The blue flames are exactly the color you want to see coming out of your gas fireplace or kitchen stove. Having a blue flame with a gas fireplace or any other gas-burning appliance is a sign that the fire being generated is healthy. Read on to find out more about what exactly that means.

What Do Blue Flames Mean?

You now know that blue flames are good when it comes to any type of gas fireplace.  But what exactly do the blue flames mean? Blue flames generally mean:

• Proper heat is being generated
• Perfect combustion is occurring
• Proper fuel usage is taking place

Proper Heat Is Being Generated

The bluer the color of the fire, the healthier that fire is. This means that all the chemicals are mixing properly, and it is at the proper heat setting. Blue flames generated from liquefied petroleum gas (LPG) tend to burn at around 3,600ºF.

Methane gas (natural gas) burning at the proper temperature with a blue flame is roughly 3,560ºF. In comparison, the heat generated within orange and yellow flames is roughly 2,400 to 2,700ºF. The blue flames are much hotter.

The heat generated by blue flames is preferred when using gas to cook and heat any liquid. That is because it will take time to heat water or cook food than it would with the orange or yellow flames that burn at cooler temperatures. 

Proper Combustion Is Occurring 

For a flame to occur, there must be some type of combustion between the fuel and the air. Darker flames mean the combustion is more efficient and the flames are hotter.

If your flame is any other color than blue, odds are that you are wasting gas and the fire will not be as clean. Guaranteeing that you are completing combustion will ensure that you are not wasting gas (or money).

Proper Fuel Usage Is Taking Place

When you burn anything, you need fuel to get a fire going and to maintain that fire. Regardless of how long you want the fire to burn, you want to be sure that you are not wasting any fuel.

When the flame on the gas fireplace burns blue, as stated above, you can be sure that combustion is happening at the nominal level. That means that you are using the least amount of fuel possible for your gas fire.

Is a Blue Flame Safe on a Gas Fire?

Since blue flames mean that your gas-burning appliance is working properly and efficiently, they are safe. The blue color is indicative that everything is mixing properly and burning hot. Any color other than blue or violet provides less heat. 

You will see blue flames on: 

• Bunsen burners
• Gas stoves
• Kitchen stoves
• Deep fryers
• Furnaces

Please note that the bluish colors will change once you add something to the gas, like wood. Adding wood to the fire will cause the color to change from blue to the colors we are all familiar with, yellow and orange.

Changing Colors

It’s typical for the blue flame to change to orange and yellow once any wood is added. This does not mean that something has interrupted combustion. Rather, it is a result of burning wood.

The flames will switch from blue to yellow and orange as the wood that you are burning begins to heat up. This is because the oxygen level in the fire shifts as the wood heats up and the combustion levels begin to vary.

Your flames switching from blue to yellow is nothing to worry about as long as you are burning something besides gas. If the color of your flame changes when you have not added anything like wood, that means that your air mixture needs adjusting.

Can You Adjust the Flame Color on Gas Fireplaces?

For those of you that prefer the traditional colors of fire as opposed to blue flames, you do have the ability to change flame colors without adding scary chemicals. If you want orange flames, you can get them by intentionally sacrificing proper airflow.

While the method varies depending on the fireplace model you have, you generally need to:

• Access the air mixture area of your gas fireplace
• Locate the set screw(s) that control(s) the fireplace’s air mixture
• Adjust the set screw to change the air mixture until you get the desired color

Access the Air Mixture Area

Again, without knowing the exact model of the gas fireplace you have, it is difficult to tell you exactly where the air mixture control will be. However, follow the gas line to where it enters the actual fireplace.  

Once you have located that area, there may be screws that hold a plate in place to protect the area. If that is the case, remove the plate to access the air mixture area.

Locate the Set Screw(s)

There will be some type of valve cover with holes that controls the amount of air that enters into the gas fireplace. On that valve cover, there will be at least one screw that holds the cover in place.  

Adjust Set Screw

Once you have located the set screw, loosen it until you can move the valve that controls airflow into the gas fireplace. Adjust the valve to adjust the level of air that is entering the fireplace.

Once you have adjusted that, carefully light the fire to determine the new flame color.  Adjust the valve until you have the desired color and then secure the panel over the air mixture control area.

What Other Flame Colors Can Gas Fireplaces Have?

As stated above, the proper flame color for any type of gas fireplace is blue. Other flame colors are possible, though these indicate that there is a problem with your fireplace. Some of the other colors you might see in a gas fireplace are:

• Orange
• Yellow
• Red
• Purple
• Green

Any flame color other than a shade of blue means that combustion is not happening properly. If you are seeing orange, yellow, red, purple, or green flames, the airflow inside your fireplace is not set properly. Unless, of course, you intentionally adjusted the airflow to achieve flames with an orange or yellow color.

If you did not adjust the airflow to your gas fireplace and you are seeing any color other than blue, you either need to adjust the airflow to repair the problem or check for any type of contaminants that have gotten into the fuel line. Contaminants could be anything from dust, dirt, or rust seeping into the airflow.  

Final Thoughts

For those of you less familiar with gas fireplaces, you may have had questions about the blue flames those fireplaces produce. You can rest easy knowing that those flames are totally normal. Beyond just being normal, blue flames mean that your fire is healthy and that you are not wasting gas or fuel.

As stated above, the blue color will change to yellow or orange if you decide to burn something like wood in the gas fireplace. Know that the color change in this instance is normal as the wood presents a change to the combustion occurring within the fireplace.

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