How to Properly Vent a Pellet Stove

Pellet stoves, designed for supplemental heat, run on wood pellets, which means they require good ventilation and regular maintenance in order to keep homes safe, the air inside clean and ensure the stove is functioning properly.

The installation and venting process of your pellet stove requires consideration of many details. For instance, it’s good to remember that warm air rises, which means your stove will be of best use to you on the ground floor unless you’re using it to heat a specific room. Also, beneath the stove, you must have non-combustible floor protection like stone or tile that extends six inches beyond the front of the stove. This detail might dictate where you place your pellet stove and how you choose to vent it.

The good news is that pellet stove manufacturers often provide the proper venting requirements and guidelines to make sure that everything is working up to par, allowing you to keep your home at just the right temperature as well as keeping your family safe, the air clean and your wallet happy. There are many professionals and experts whom you can call to get the job done. WE STRONGLY recommend professional installation. Don’t try to be the handyman hero. It will only lead to future problems.

What is Pellet Stove Venting?

Pellet stove venting is part of the installation process as the stove has to be routed and vented to the outdoors, directly through the wall into the open air. In this installation, there is no visible pipe inside your home got a clean and polished look. The venting expels combustion gasses and smoke–produced by the pellets–outside of the home and into the open air.

There are two crucial aspects to consider during this process. First, you must follow local codes and regulations, ensuring that the fresh air intake—the supply of fresh air coming into the pellet stove and the room—is available. Secondly, since pellet stoves produce a fire that burns pellet fuel and creates heat, you must take into consideration the flue–a part of the stove involved in filtering and expelling unnecessary pellet stove air from the home. Prior to the installation, decide where you’re venting the flue. There are multiple choices depending on your home and the intended use of your stove.

Why Is Proper Wood Pellet Stove Venting Important?

If your pellet stove is not properly vented it won't burn efficiently and safely. It will also create emissions, which impact the environment. Improper venting also prevents your stove from giving off an optimal amount of heat, causing you to use more pellets. Lastly, proper venting is critical to operating a pellet stove safely. 

How to Properly Vent a Pellet Stove

Venting diagram through a roof or wall

When venting your pellet stove there are a few options from which you’ll choose. Commonly, pellet stoves need a type ‘L’ vent pipe. Usually, a 4" vent pipe requirement is standard. The L-vent uses a small air space between a stainless steel inner pipe and a galvanized outer pipe. Since pellet equipment exhaust is pressurized, all the joints between the pipes need to be siliconed or have a tight, sealed or gasketed connection.

However, whichever method you decide upon, we can’t stress how important it is that you call a professional to help you with the procedure.

A Closer Look at Pellet Stove Installation Methods

Vertically (through the roof)

Pellet Fuel Institute (PFI), Vertical venting through the ceiling and roof has the advantages of keeping vent gasses warm and of providing natural draft to prevent problems in an unexpected shutdown.” The stove is able to remain in a central location, inside your home, while the exhaust is discharged safely and efficiently through the flue. In order to vent, you’ll usually need a four-inch vent pipe, but in some cases, a three-inch pipe is used. It all depends on the pipe’s run length and the number of bends. Should your stove’s manufacturer declare it requires a four-inch pipe, this is the way the manufacturer designed the product. Any other pipe will throttle the stove.

While most pellet stoves can be fitted with a flue system, designed to direct the exhaust gasses away from the house, if a flue already exists from an old fireplace or wood-burning stove, the existing flue is typically used. But usually, a vertical section of the flue is installed, extends out of the roof, and features a vented top cap. A vertical flue provides better protection against cold weather conditions as there is less chance for condensation inside your home.

It's important to ensure that this outlet (the pipe extending outside the house) is at least three feet away from the stove's air inlet pipe. The last thing you want is to have exhaust traveling back into the house and discoloring both the exterior and interior walls. A great way to protect your walls is with heat-resistant paint made specifically for fireplaces and heating stoves. According to a blog post on the Rawlins Paints website, “[There’s] heat-proof paint for fireplaces and firewalls exposed to higher-than-normal temperatures. Muuri ensures a breathable surface that is heat resistant up to 300°C [572°F] (in standard white) and 180°C [356°F] (in its 8 tinted colors), protecting the walls surrounding your fireplace or stove with a striking finish.” Rawlins Paints explains that the paint works with “fireplaces and surrounds” including those that are:

Horizontally (through a side wall) with a Small Rise

Horizontal venting is an easy and less expensive approach. All you need to do is connect your vent pipe to an adapter behind the stove, running it through the wall adapter plate to the outside of the house, ensuring it’s at least six inches from your home’s exterior. Additionally, you’ll want it to be over three feet above any air inlet pipes within ten feet of the area. We urge you to check your local building regulations and find out how far the outlet should be from any windows, doors or inlets that bring air in from outside.

 

If venting your pellet stove horizontally, get a vertical rise with the L vent pipe before going through the side wall. First, it prevents smoke from entering the home if there is a power failure. That is a safety hazard. Second, it removes excess air from inside the stove when you start using it, again after an interruption in power. If you don't have enough vertical rise, the air stays trapped inside the stove and causes problems with your fire.

There are two ways to carry out this type of venting. The riser can come directly from the stove and reside inside the room or outside of the house. If the riser is inside, there’s an efficiency boost as the warm pipe gives off extra heat. Either way, include a wall protector plate on the outside.

Using an Existing Chimney to Vent your Pellet Stove (when replacing a wood-burning stove with a pellet stove)

Pellet stoves can also vent through an existing masonry chimney. According to Hunker, a home and design website, in an article entitled, How to Install a Pellet Stove Through the Chimney, “Installing a pellet stove pipe in an existing chimney requires a chimney liner. This is a metal pipe that attaches to the pellet stove at one end—typically with a pellet stove pipe chimney adapter—and extends all the way through the chimney and above the roof at a suitable clearance. A half-inch layer of insulating material will also be wrapped around the chimney liner to keep the air hot as it travels up the chimney, thus reducing creosote buildup.”

If you don’t possess the proper permits yet still install and vent your wood pellet heating stove, liability issues will arise when you’re looking to sell your home or with your homeowners’ insurance. If you are experienced and obtain the necessary building and mechanical permits from your local building department, everything should go smoothly. However, we highly recommend leaving the pellet stove venting to a licensed stove installer. There are many qualified people and companies. If you can’t find one through your purchasing dealer, feel free to check out Harman’s directory.

Step-by-Step Directions on Installing Your Pellet Stove

We know we’re starting to sound like a broken record. Call a professional when it comes to installing or modifying pellet stove venting. It’s not safe to take a chance with potentially hazardous outcomes. Most likely, you can purchase your stove with installation included. However, if you’re one of those curiously handy types and need to understand the process, we’ve included a list of websites below where you can learn the steps to venting your pellet heating stove.

Maintaining Your Pellet Stove Vents

How do I clean/maintain my vents?

Although pellet stoves are clean-burning heating appliances, they still produce some waste in the form of ash. You’ll have to clean it out of the exhaust vent.

Before cleaning, turn off your stove and give it time to cool down. It’s safest to wait 24 hours after last using your stove before cleaning it. Then, unplug the stove and put on gloves and a mask for safety. Next, remove the vent pipe from the stove and clean it from the outside opening with a three- or four-inch plastic or flexible steel-bristled brush. Be sure to avoid stiff-bristled brushes. They can potentially damage the pipe. You can also clean the chimney vent pipe using a Gardus Soot Eater. It’s a tool that cleans the pellet stove vent or chimney in under two minutes.

We’ve included a video tutorial from YouTube by 5 Minute Fix It, in which they show their followers how to clean a pellet stove exhaust vent using the Gardus Soot Eater. The video features a Harman Pellet Stove and demonstrates cleaning the vent.

Most likely, your pellet stove dealer can provide this service regularly. Be sure to ask about it during your purchase.

How often do I check my vents?

While every pellet stove is different, you should check your manual for the precise answer. According to Energex, a North American wood pellet manufacturer, in an article on their website entitled, Pellet Stove Maintenance Tips, they state, “On average, a deep clean once a week could be useful. However, every pellet stove is different, and it’s hard to say a specific time frame of how often you should clean your pellet stove. Check your stove’s manual to see if there are any cleaning recommendations. If your manual doesn’t specify or if you feel like you use your stove frequently, clean once a week. You may also clean the different components of your stove at different rates depending on your use and preference.”

The goal is that the buildup in your vent pipe doesn’t get thicker than a quarter of an inch. Upon first getting and installing your stove, a good rule of thumb is to check it every so often and inspect the situation. That way, you’ll know how much time can lapse between cleanings.

How often do I clean the other parts of my pellet stove?

 

Routine maintenance of your stove includes more than the vents. Let’s look at each stove part and how to ensure it stays clean. 

Pellet Stove Maintenance Tips, an article we referenced above and found on the Energex website, goes over all of the parts of your pellet stove that need to be regularly maintained. Below is a listing with brief directions. 

  • The cleanout tee: A T-shaped vent pipe behind the stove.
  • The opening of the vent pipe: Clean to where the vent ends, which could take you to your roof or somewhere outside.
  • The remainder of the vent pipe: You must invest in a specific brush that gets all the hard-to-reach areas.
  • The inside of the firebox: You must sweep away the ash inside your stove. Make sure to sweep toward the bottom.
  • The glass: Once it’s reattached and clean, brush away any ash on your stove’s glass.
  • The outside: Wipe down the outside and place your firebox ash into a metal container. If you have a garden, by all means, use it as fertilizer.

Last Words of Advice

While the benefits of using a pellet stove to heat your home tip the scales, it’s important to remember that it comes with some extra decisions, labor and care. From purchase to maintenance, your pellet stove process will run smoother if you research and answer your questions beforehand. Discuss where you’ll install it; the type of venting that’s best for your home; if you’ll have time to carry out regular maintenance yourself; or if you plan on hiring a professional. With more knowledge comes wiser decisions.

Contact Harman for additional information, use our website’s locator tool or call your local dealer.

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