Should I Use Chimney Extension on My Outdoor Wood Furnace?

Should I Use Chimney Extension on My Outdoor Wood Furnace?

Do I really need a chimney extension on my outdoor furnace? Is it worth the extra money?

We know that these questions have been bothering you since you got your outdoor wood boiler. You may have seen that your neighbors who also own outdoor boilers are using chimney extensions, in fact, they are using longer pipes on them!

All of us at have chimney extensions on our outdoor wood-burning boilers - MANY customers do too. The big advantage is that it just gets the smoke away. Outdoor Wood Stoves don't produce too much smoke, but an extension just gets the smoke up and away. Very nice!

So yes! We recommend having a chimney extension! 

Also, taller chimneys help keep some smoke from your windows. And the neighbors!

Chimney extensions are known to extend the life of an outdoor boiler because they enhance draft and hence combustion. Read more HERE

How to Install Chimney Extension?

chimney extension

Extend the chimney in more densely populated locations, to a height that is above the neighboring structures' rooflines. 

Chimney Adapter

To strengthen the extension, we recommend using the twist-lock chimney adapter before putting the chimney extension. The inside diameter of the adapter should correspond to the diameter of your chimney.  Click HERE to purchase a chimney adapter. 

chimney adapter

Insulated Chimney Extension

chimney extension

A good chimney extension will EXTEND the life of your outdoor wood burner and we all love having them on our boilers, but the wrong type of chimney will kill your boiler in 6 months. NEVER use an uninsulated chimney extension. NEVER.

Because the truth is….

The Single FASTEST Way To Destroy Your Outdoor Wood Boiler having an UNINSULATED Chimney Extension on your boiler.

All wood fuel, even the most seasoned hardwood, contains moisture. We want that moisture to exit the furnace harmlessly in the form of steam. 

When you have an uninsulated chimney extension, the exhaust COOLS on its way out, then steam condenses on the inside of the chimney, and forms the most caustic creosote which drips back down into your outdoor wood furnace and eats through the steel. NOT GOOD!

The solution is simple - if you need a chimney extension, make sure you have a Triple Wall Insulated Extension. This prevents the exhaust from cooling as it exits the outdoor wood burner! No condensation, no creosote, NO WORRIES!

Remember that you must use the proper diameter extension - they come in several sizes, but the most common are 6" and 8" diameter. Most extensions are 48" long.

If your outdoor boiler is near or under a roof, you must extend the chimney above the roof using only an INSULATED chimney extension. Learn more about chimney extensions from at this link HERE. 


Chimney Cap

chimney cap

Using Chimney caps on outdoor wood boilers is NOT optional. These chimney caps are a very high-tech designed product that provides three critical functions:

  1. Keep the rain out - This one is obvious. 
  1. Spark arrester - Depending upon the wood you burn and local wind conditions, you do not want sparks leaving your outdoor boiler and igniting your woodpile or anything else nearby. The chimney cap is a spark arrester and knocks down any sparks that get out of the chimney.
  1. Prevent downdraft - If you ever have high winds (and who doesn't!), the special design of the chimney cap will prevent high wind from sucking heat out of your boiler and adding air to the fire, particularly when the furnace is in the idle mode when you don't want the fire to burn. 

This can severely damage your outdoor wood burner steel if the furnace fire continues to burn when it should not.

So please remember that chimney caps are NOT optional equipment for outdoor wood-burning boilers. They are required and provide very important functions that enable you to continue to save money on your heating bills for decades!

Keep in mind that you need to remove the chimney cap once per year. (remove any extensions also to access the inner chimney). You can also order a chimney cap replacement 8" HERE and our 6" HERE. 

If you've never removed a chimney cap before, it's sometimes too late to save the chimney cap and since it has to be removed, it'll be damaged in the process.

If you have any concerns about your installation or you need outdoor boiler chimney parts and other replacement parts, please call us or send us an email and we will help you get your installation in perfect condition before the heating season starts - so you can Keep Your Family Toasty Warm and Comfortable for Decades!

Call Us TODAY at 231-861-8200 M-F 8 am - 6 pm EST, or go online at to browse for more outdoor wood boiler parts!