Pellet Stove Glass Gets Black—What To Do?

Sitting in front of your pellet stove on a cold, wintry night watching the flames is a relaxing activity, but this can be ruined if the glass doors of the stove are continuously turning black. So how can you fix this problem and get back to enjoying the fire? We've done the research to help you.

Here is a checklist to help keep your pellet stove glass clean:

Be sure that you are burning high-quality pellets.
Be sure that your settings match what is recommended in the appliance manual.
Check for leaks in your intake and exhaust.
Routinely and properly clean the stove, including the intake valve.
Have a professional regularly service and clean your stove.

So now we've given you a quick overview of what you can do to make sure your stove is working at top efficiency so that the glass will stay clean and clear. But perhaps you would like more details and instructions. Keep reading to learn more.

Why Does The Window On My Pellet Stove Turn Black?

If the window on your pellet stove turns black, this indicates an issue with either the fuel or ventilation. To understand this a bit better, we should take a look at the design of pellet stoves.

The Creation Of Pellet Stoves

The pellet stove was invented in the 1970s. This was at the height of an energy crisis and oil shortage, and this stove was meant to efficiently heat a home by burning recycled materials. They are also doing so without filling the home with smoke and unclean air. Coincidentally, you need very little electricity for a pellet stove.

So how is this different than the stoves that came before? The pellet stove is different because it came with a ventilation system - including an exhaust fan, an air intake, and an air outtake valve. They don't require a chimney, which allows much of the heat from wood stoves to leave the home.

Burning Cleanly

Many materials that we burn for heat, including coal, produce creosote, but this chemical isn't in high-quality pellets. These pellets burn cleanly as an eco-friendly heat source. However, if you use fuel for your pellet stove that does produce creosote, this could cause black, tarry soot to appear inside of the stove.

On the other hand, if there is an issue with your stove's ventilation system, this also could prevent the stove from burning cleanly and thus will leave an unsightly film on its glass window. Whatever the cause for soot on your pellet stove glass, you'll want to follow this checklist to ensure that your pellet stove is clean.

High-Quality Pellets

Because of the reason above, purchasing high-quality pellets that are specifically for use in pellet stoves is essential to having a clean-burning stove and clear window glass.

You can discern whether pellets are high-quality by visually checking them for production failures and burning one bag at a time to see how cleanly and efficiently they burn.

When checking pellets visually, you will want to pay attention to the outside of the pellets. Are they smooth? If so, this means that they have been compressed correctly. If not, that the manufacturer did not use a correct "compression ratio."

You will also want to be sure that there are no frequent cracks or crumbling in the pellets. This indicates that the pellets had too much moisture during compression, and that means that they will not burn efficiently. This is best done when the weather isn't bitterly cold but in early fall. You may try a few different brands one bag at a time to see how the pellets burn.

This test is especially important because if the flames are blue or green, this indicates that the pellets have additives. These additives mean that the pellets will not burn cleanly and could leave behind unwanted materials. Among these materials is the creosote that will leave tarry, black soot on the window glass.

Stove Settings

Although all pellet stoves follow the same basic blueprint, each has its own signature differences in design. Because of this, you should be sure to keep your specific pellet stove's manual on hand.

Each part of the pellet is stove works in conjunction with the others, to create clean, efficient heat. However, if one of the settings is off, this could prevent the ventilation system from working properly and thus cause an unclean burn.

If that happens, you will most likely experience some issues with the pellet stove becoming dirty, including the window glass. Take a look at your manual and be sure that all the settings are where they should be.

Checking For Leaks

You should know that checking for and fixing leaks on a pellet stove may be best left to a professional as fixing the leak incorrectly could compromise other areas of the pellet stove's system.

If you'd just like to rule this out as a potential issue, there are a couple of rather simple ways to check for leaks on your pellet stove. Firstly, look around the outside of your pellet stove. Because this system should ventilate the soot, if you find a build-up in a certain area, this is most likely where you have a leak.

Another way to check is to shine a flashlight inside of the stove when it's otherwise dark in the area. If the stove is completely sealed, you will see no light exiting the stove. However, if there is a hole, you will see the light shining through.

Cleaning The Stove

Even though a pellet stove burns much cleaner than others, it still needs regular cleaning to both work at its highest efficiency and have the most beautiful, comforting look.

Cleaning the exterior of the stove is quite easy. You can use a spray bottle filled with vinegar and water at a 1:2 ratio and a few drops of dish soap. Using this solution, spray the exterior of the stove and wipe it clean.

The innards of the pellet stove are the most important to clean, as this prevents issues with the ventilation system. The inside of a pellet stove may have rust. This is normal, especially for older stoves. If it occurs, you may use a wire brush to remove the rust.

Check out these wire brushes on Amazon.

The brazier is the most important area to clean to prevent issues with the air intake and outtake. You can use a home vacuum or a shop vac for this task, removing all visible ash. If you see any scaling, you may have to remove the brazier and clean the grate more thoroughly with a wire brush.

In addition to these areas, you will also want to clean the burning pot and the trash door or ash pan. You can do this can easily by sucking up the ashes with a vacuum.

How Do You Clean Black Pellet Stove Glass?

When a pellet stove is working correctly, the stove glass will only have a thin layer of ash that you can remove easily with a dry paintbrush or duster.

However, if the glass is very dirty or has a thick layer of creosote on it, you may have to use a cleaner. Only use a neutral glass cleaner with no abrasives, and be sure to only have the cleaning solution in contact with the glass. Wipe it clean with a lint-free rag.

Take a look at this glass cleaner on Amazon.

How Often Does A Pellet Stove Need To Be Cleaned?

On average, you should clean a pellet stove every two weeks when it is consistently burning, but you could stretch the time between cleanings a bit if you are using high-quality pellets or if your stove is a high-efficiency model. On the other hand, if your stove is on the older side or if you must use pellets of lesser quality, you may have to clean it once per week.

What Happens If You Don't Clean A Pellet Stove?

If you do not clean a pellet stove, there will most likely be many issues with the system and could cause the appliance to fail altogether. The ventilation system is key to both removing excess ash, preventing clogs, and kindling the fire.

Having Your Pellet Stove Serviced

Having your pellet stove regularly serviced is essential to keeping the system working properly as well as keeping it clean! Ideally, you should do this before the winter season, and you can obtain a technician by contacting your stove's manufacturer.

The technician will check for, and fix, leaks. They may also deep clean the stove, including the intake and outtake ventilation system.

In Closing

Pellet stoves are an eco-friendly and comforting heat source. But if issues arise with a consistently black window, you may be missing out on one or both of these benefits. Keep in mind that this issue is often due to a problem with the type of fuel or with the ventilation system.

You can attempt to remedy this by purchasing quality fuel, adjusting settings, checking for leaks, cleaning the stove, and having a professional regularly service the stove. Whatever the reason, we hope that you can resolve this issue quickly so that you can get back to enjoying your pellet stove.

Want to learn more about home heating? Check out these related posts:

How Much Electricity Does A Pellet Stove Use?

Do Vented Gas Fireplaces Need A Chimney? [Or How Else To Vent Them]