Why Is Kerosene Heater Burning Black Smoke?

Kerosene is a type of fuel that you can use to provide heat. A Kerosene heater is an appliance that heats the space using this fuel type. 

It may produce black smoke when it is in use. But there are ways to make it stop doing so.

Check if the Kerosene has been diluted with water or other liquids by pouring some out onto a white surface and letting it evaporate for about 10 minutes.  

If the liquid disappears, you should pour more in before lighting your heater again.

What Causes Kerosene to Smoke Black?

Kerosene heaters were notoriously smelly and sooty in the past, but modern models should provide consistent heat while operating smoothly and effectively. 

If your kerosene heater is smoking, there might be a problem with one of the following factors.


If you have a heater that needs a wick, you will need to buy the wick made for your heater. If it has a fiberglass top and cotton bottom, do not use an all-cotton wick.

Replace your wick as needed according to the manufacturer’s instructions. You should also consider adjusting your wick, it might be too high.


Kerosene comes in two varieties, 1-K and 2-K. Portable, unvented kerosene heaters are only permitted to use 1-K fuel.

1-K is not as clean-burning as clear kerosene. So if you’re using 1-K, try switching to a different type of fuel.

Kerosene, being extremely inexpensive, leads to carbon build-up, which eventually results in smoke. Only burn high-quality fuel.

Burner Cylinder

Another reason your kerosene heater is producing black smoke might be the burner cylinder. If your burner cylinder is clogged or dented, it needs to be replaced.


Also, check your chimney to ensure it’s well seated. If it’s not well seated, look for a high flame on one side of your heater.

Dry Burn

If all of the above factors have been checked and there is still black smoke coming from your kerosene heater, you may be experiencing a dry burn.

A dry burn happens when the fuel isn’t vaporizing properly, caused by low-quality fuel or an incorrect wick adjustment. 

Stop using your heater until it has been serviced by a professional.

How to Prevent Kerosene Heater from Smoking

If your kerosene heater is emitting a cloud of sooty black smoke, it’s an indication that the fuel-air mix may be incorrect. Make sure the chimney is sitting securely in place. Otherwise, you could observe a very tall flame on one side.

Use the heater in a draft-free area and adjust the wick with the wick adjustment knob to suit.

Here are several reasons why your kerosene heater produces black smoke and how to stop it.

You May Be Using the Wrong Fuel

Kerosene comes in two grades: K1 and K2. The K1 is the only type used for unvented kerosene heaters.

Therefore, kerosene may not be the best choice. Kerosene is indeed is kerosene. However, if your first reaction was to grab K 2 since “kerosene is kerosene,” you should reconsider it. Not all types of kerosene are created equal.

Even if the package reads “K 1 kerosene,” it doesn’t imply that it’s ideal for use. Red-colored K 1 kerosene, for example, includes dyes; thus, the burn will not be as safe as with clear kerosene.

If you’ve been using the red-dye variety for a long time, consider switching to a clear type. 

The quality of the fuel will also influence the amount of smoke and smell emitted by the heater.

Using low-quality kerosene or diesel fuel will cause problems. The heater may start to smoke and smell like kerosene if you use these.

You May Be Burning the Wick 

This isn’t specifically a problem with some kerosene heaters, but some kerosene heaters recommend against burning the wick dry – something directly related to the quality of the wick.

If you burn it too dry when you shouldn’t, there’s a risk of smoke build-up. Ensure you’re burning the wick properly and that the fuel tank is empty.

Your Cylinder Has an Issue

If you’ve had a forced air kerosene heater for a while, but it still seems to be leaking smoke, there may be an issue with the burner cylinder.

Inspect whether it’s damaged or blocked. If it is clogged, you may be able to clear it yourself or have it taken to a professional. 

However, if it is dented, there is nothing else for you to do, and you must take it to a professional

The Chimney May Not Be Well Seated

Placing the chimney correctly is another approach to prevent a kerosene heater from smoking. 

If the burner chimney isn’t positioned correctly, kerosene heaters may create smoke. Check for a very high flame state on the heater’s side.

You Might Be Using the Wrong Wick

Yes, the type of wick you’re using might have an impact on whether your kerosene burner emits smoke.

For instance, if you’re using a generic wick adjuster, it might not work properly on the device.

If your kerosene heater wick is typically made from cotton with a fiberglass top, don’t use one entirely composed of cotton just because “it’s less expensive.”

In most situations, the manufacturer will suggest which kind of kerosene heater wick you should use.

Purchase the recommended wick for your unit. Also, be sure to replace the wick as instructed since an old wick might be a smoking wick.

If the wick adjuster is correctly positioned and new, there’s a chance you installed it too high. Adjust it to the manufacturer’s recommended height.

How To Clean Kerosene Heater Wick

As the wick of a kerosene heater begins to get dirty, it can produce black smoke when in use. This is because the oil that flows through the wick cannot evaporate due to its inability to absorb into the fibers of your wick.

Here is how to clean a kerosene heater wick:

  1. Carefully examine the wick. If the top of the wick is discolored with tar and other remnants of kerosene, it’s time to burn it dry.
  2. Turn off the heater and allow it to cool. Remove all kerosene from the tank. Light the wick to its fullest length and set it aflame. Allow the saturated wick to burn until it goes out, burning off any tar deposits.
  3. Remove the wick if you think your heater’s tank is waterlogged or contaminated with oil. Soak it in wood alcohol for 5 minutes to let the alcohol drive out the water. Let the wick’s air dry before putting it back into your heater.

Another method that some people may prefer is simply buying new wicks altogether, which is an inexpensive way of fixing this issue. 

All you need to do to replace them with the old ones still attached is remove both ends, drop at least half an inch of fuel inside and allow it to sit for a few minutes before placing back onto your heater unit. 

When done correctly, there should not be any black smoke emitting during operation afterward until it needs cleaning once more in about four weeks or so, depending on how frequently it’s used.


It is important to ensure your heater is burning clean and clear. If you notice black smoke, it could be a dirty filter or lack of proper airflow. 

Ensure the fan behind the flames is running smoothly and that there’s no loose wiring in the area, which may cause an electrical fire hazard.

For questions or feedback regarding this topic, feel free to ask them in the comments section below or reach out through email.