What Causes Black Smoke Coming from Your Patio Heater

Black smoke coming from your patio heater can be caused by a number of different things. It could just be the burner running out of fuel, or it could simply mean that you’re using too much gas and need to adjust your settings. Check for these potential factors before contacting an expert about other solutions.

The “smoke coming out of heater vents in house” is a common problem that many homeowners face. The black smoke can be caused by the air intake system, or from the burner itself.

Related Post: Best Table Saws

Patio heaters may make time spent outside more pleasurable, but learning how to operate and maintain one may need some research. The development of black smoke when using a propane-powered patio heater is a regular problem that customers with these heaters have. 

Black smoke from your patio heater may be caused by three things:

  • The heater’s propane burn is being affected by an incorrect gas combination.
  • The substances on the heater’s exterior are being burnt off.
  • Debris and rust from the inside are being burnt.


There are numerous more particular reasons within each of these three categories, ranging from malfunctioning components to bad maintenance. We’ll go through how patio heaters are meant to operate and how to troubleshoot any problems you may have with yours.


Contents Table of Contents

  • Why Your Patio Heater’s Black Smoke Is Dangerous
  • Propane heaters need a certain oxygen ratio to operate. 
  • Substances Burned Off Your Heater’s Exterior
  • Examine Any Potential Internal Issues With Your Patio Heater
  • The Risk of Black Smoke Is Reduced With Regular Maintenance
  • Proper storage also reduces the risk of black smoke.
  • Conclusion


Why Your Patio Heater’s Black Smoke Is Dangerous

If a propane-powered flame produces black smoke, there’s a problem, as you probably know from starting up a propane grill during a barbeque. Propane is a “clean burning” fuel, which means that when it is burnt, it does not emit any toxic pollutants (aka black smoke).

This is not only excellent for the environment, but it is also beneficial for your health. Other fuels, such as the gasoline in your automobile, emit harmful pollutants that are unsafe for you to breath on a daily basis, either directly or indirectly.

Propane-powered equipment, such as your patio heater, are safe to use on a daily basis because of the precise chemical reaction that occurs when propane is consumed. Combusted propane creates carbon dioxide and water vapor under ideal circumstances, both of which are safe to have in the air surrounding your patio.

Black smoke from your patio heater, on the other hand, indicates that something else is burning alongside the propane or that the propane isn’t being used properly. We’ll go over how the latter might happen in the following part, as well as what you can do to avoid this source of black smoke from your patio heater.


Propane heaters need a certain oxygen ratio to operate. 

Although propane is often referred to be a “clean” fuel, this does not imply it is smoke-free. The ratio of gases delivered to the ignition source in propane-powered appliances is controlled by specialized components. Fuels may burn effectively when the right number of certain gases is available.

In most circumstances, oxygen is the most important gas. Fuels may experience “incomplete combustion” if there isn’t enough oxygen available. When this happens with propane, the ensuing black smoke may be very hazardous to your and your family’s health.

Incomplete propane combustion, on the other hand, creates carbon monoxide instead of water vapor and carbon dioxide at acceptable levels. Inhaling large quantities of this gas, whether all at once or over time, may be dangerous to your health in the short and long run.

Carbon monoxide poisoning symptoms range from the seemingly harmless headache and slight dizziness to the more serious:

  • Vision is hazy
  • Breathing problems
  • Being knocked out 

Although the chances of significant harm are reduced when exposed to carbon monoxide in an open-air setting such as a patio, low to moderate levels of exposure may still have cumulative consequences. Fortunately, the color and look of your patio heater’s flame may help you determine if any black smoke you observe is the result of an inappropriate gas combination. This page has further information about patio heater safety.

How to Tell if Your Heater Is Using the Wrong Gas Mixture

Changes in the look of your patio heater’s flame might be the strongest clue that the propane to oxygen ratio is wrongly managed, apart from the black smoke itself. While too little propane may distort the look of the flame, it’s unlikely to result in black smoke, so we’ll concentrate on the opposite end of the range.

The flame created will be substantially greater than typical if there is too much propane in relation to the quantity of oxygen. Another telltale clue is that the flame will be yellow to golden in color over the most, if not all, of its length. 

Right now, the most popular stories are

How to Hang String Lights in a Backyard Without Trees: 7 Methods

Is a Hot Tub Safe to Use on Gravel? (And Why You Should Use It)

Squirrels in the Backyard: What to Feed Them


Propane-powered flames are expected to have a yellowish-orange inner core with a medium blue outside section when burnt at the correct gas ratio. Consider what you’d see if you turned on a gas stove. If your patio heater’s flame is much more yellow than that, it’s because it’s operating on a low propane-to-oxygen ratio.

Identifying the Problem That Leads to Incorrect Gas Mixtures

The ratio of propane and oxygen in your patio heater might be caused by two primary components:

  • The mixing valve for air
  • regulator of gas

Either (or, more improbably, both) of these components might be faulty, resulting in an inappropriate gas combination and black smoke from your patio heater. There are several solutions depending on which portion is creating the problem.

Obviously, if either part is faulty, it will need to be replaced. However, if the issue is The mixing valve for air, it may not be an issue of the individual part that you put in but rather the model. 

If you ever replaced The mixing valve for air yourself, you may have thought that any model would do, when actually propane-powered appliances often require specific models to get the correct gas ratios. Make sure that any replacement air mixer valve you’ve installed actually meets the specifications outlined in your patio heater’s owners’ manual.

On the other hand, if the improper gas mixture is coming from a malfunctioning regulator of gas, the issue could be caused by an incorrect pressure adjustment. To effectively regulate the amount of propane released into the propane burner, the regulator of gas needs to be calibrated first, a process you can either have done by a profession or reference your owners’ manual to doublecheck yourself.

Substances Burned Off Your Heater’s Exterior

If you’ve ruled out an inappropriate gas mixture as the source of the black smoke, it’s possible that something else is being burnt alongside the propane in your patio heater’s fuel tank. 

We’ll talk about the most probable outside and internal sources of debris that might be causing the black smoke you’re seeing in this part and the following. In any case, the most efficient strategy to address this problem is to keep your patio heater in good working order. 

In certain circumstances, though, seeing black smoke is natural and not symptomatic of any concerns that need to be addressed, as we’ll discuss first.

When using a new heater for the first time, black smoke is common.

When patio heaters are initially utilized, one of the most typical times they emit black smoke is when they are turned on. This may be alarming to new owners who were sold on the gas heater’s clean-burning qualities, but it’s really pretty typical.

Many patio heaters will still have lubricants and oils on them after manufacture and assembly since they were transferred during the manufacturing process. When this occurs, when new owners turn on their patio heaters for the first time, black smoke is created as the residue burns.

The length of time the black smoke continues will tell you if this is a “surface” issue or an ongoing problem. In most cases, the black smoke created by burning off manufacturing-related compounds should only linger for the first thirty minutes after you turn on your heater.

If your problem lasts longer, it’s possible that it’s caused by compounds on the outside of your heater, but not ones that are related to how recently you acquired it.

Make that your burner and ports are in good working order.

Carbon sediment may build up in the propane pilot and burner of your patio heater over time. This is most common when the burner isn’t cleaned on a regular basis, since it’s an issue that becomes worse with time. 

When a little quantity of carbon silt builds up, it makes it more difficult for propane combustion’s gaseous byproducts to escape. Because the carbon dioxide created has nowhere to escape, it condenses and forms black sediment on the burner and ports. 

The more often this occurs, the more difficult it is for carbon dioxide to evaporate, and the more sediment accumulates over time. This issue may be swiftly resolved by wiping down the burner or using the cleaning technique recommended in your owner’s handbook. 

When silt in the ports has solidified and gotten jammed, the most challenging challenges develop. In such circumstances, you may need to break up and remove the silt using something like a paperclip.

If you’re still experiencing problems with black smoke after checking the various causes we’ve discussed so far, you might be dealing with toxins that have built up within your patio heater.

Examine Any Potential Internal Issues With Your Patio Heater

As we’ve previously said, sediment may readily accumulate on the outside of your patio heater, resulting in black smoke. However, if you let this carry on for too long, the sediment may get up within your patio heater’s vital components.

The propane in your patio heater will be housed in its own storage tank. To reach the burner, the propane will have to pass through the regulator of gas. Then, the air allowed in via The mixing valve for air and the propane both enter the burner through a specific tube, which is known as the burner venturi tube.

When insects or spiders climb inside your patio heater and leave detritus, such as spider webs, this tube might get clogged. When you turn on your patio heater, anything is in the burner venturi tube gets burnt with the propane, resulting in the black smoke you observe.

To clean this tube, you’ll need to disassemble your patio heater, and you’ll want to refer to your owner’s handbook for instructions on how to correctly remove and reassemble everything. After removing the tube, clean it well using a pipe cleaner.

Similar debris and/or silt will most likely be found in other internal elements related to the burner venturi tube. In most cases, compressed air canisters may be used to safely clean these components. To be safe, avoid applying compressed air straight from a close range.

The Risk of Black Smoke Is Reduced With Regular Maintenance

Now that you know how your patio heater may emit black smoke in a variety of ways, it should be evident how important it is to maintain it properly and on a regular basis. Identifying and repairing the source of black smoke might be simple in most circumstances, but you can frequently avoid these problems from occurring in the first place.

To begin, be sure to arrange annual maintenance for your patio heater, which includes inspecting, cleaning, repairing, and recalibrating all of its components as needed. While your owner’s handbook will provide more detailed instructions, you should:

  • Check that the regulator of gas is still calibrated for the correct pressure
  • All internal components, such as the burner venturi tube and pilot feed tube, should be thoroughly cleaned or replaced.
  • Replace any burners or pilots that look to be worn out or need to be replaced, as directed by the manufacturer.
  • Check the propane level and do leak checks.

Maintaining your patio heater on a regular basis can help you prevent black smoke and extend its life. It’s a good idea to take care of it immediately before the season when you use the heater the most. However, this is insufficient. You must also be attentive each time you start and stop using your patio heater to be a responsible owner.

When you’re ready to ignite and switch off the heater, double-check the visible connections. Wiping down the burner and its ports before and after each usage is also a good approach to keep dangerous build-up at bay. 

This will not only limit the amount of sediment that gets into the inside of your patio heater, but it will also reduce the amount of time and money you spend cleaning and/or replacing the inner tubing.

Proper storage also reduces the risk of black smoke.

Aside from appropriate maintenance, you need also consider how you keep your patio heater. In addition to reducing the generation of black smoke, careful storage ensures that your patio heater lasts a long time and is used safely.

Built-up silt and debris, whether external or internal to a patio heater, is one of the most common reasons of black smoke, as we’ve discussed. While regular usage of your patio heater may cause carbon sediment, dust that collects on an inactive patio heater can be just as troublesome.

When you’re not using your patio heater, keep it safe by storing it in a secure location with a lockable cover. A properly-secured cover may prevent dirt from building on the burner and ports, as well as reducing the amount of insects and spiders that may find their way into the system’s components.

Storing your heater in this manner will also assist to limit the likelihood of water gathering within it, making it simpler to start a flame even on days when it has rained heavily. Finally, anytime no one is on the patio or within sight of the patio heater, be sure you properly turn off the patio heater and utilize the propane manual shut off. 

Even while patio heaters are simple to use and enjoy, it’s vital to remember that improper usage and storage may have significant implications. Following these guidelines will ensure that you are doing it in a manner that enables you to enjoy your patio heat for as long as possible while being safe.


We’ve gone through a few reasons why your patio heater is emitting black smoke. While the numerous reasons may seem to be a lot to keep track of, preventing these problems is simple if you know what to anticipate and include regular maintenance and correct storage into your daily routine.

When you’re getting ready to utilize your patio heater, keep these things in mind:

  • Using a clean cloth, wipe off the burner and ports.
  • Make sure the gas ratio isn’t wrong by looking for too yellow flames in the burners.
  • After you’ve finished using the patio heater, have another towel on ready to clean it off.
  • Turn off the ignition completely, then turn off the propane tank using the manual shutoff.
  • Cover your patio heater until you’re ready to use it again.

If you make it a habit to follow these procedures, you’ll be able to rule out potential reasons if you notice black smoke again. If this occurs, you’ll have a better understanding of your patio heater and will be prepared to tackle the situation quickly to maintain your heater in excellent working order and you and your family safe. 


The “white smoke from heater vents” is the result of combustion. The combustion process creates a mixture of water vapor, carbon dioxide, and other gases that are given off as a product of the burning fuel. This is what causes black smoke coming from your patio heater.

  • electric heater smoking
  • electric water heater smoking
  • why is there soot on top of my water heater
  • oil furnace black smoke from vents
  • gas water heater smoking
You May Also Like