What type of chimney for wood stove

To prevent this from occurring, a chimney should extend at least 3 feet past a flat roof and be at least 2 feet above any roof peak within a 10 - foot radius. Contrary to popular belief, chimneys that exit the home at ground level and run outside along the exterior walls of the home are extremely inefficient.

Since hot air rises, the outside temperatures cool the gases inside the chimney , reducing draft. These cooling gases can also create condensation and a buildup of creosote. Creosote forms when warm gases come into contact with a cold surface, which is what happens when you run a chimney outside. By locating the stove in the center of your home, the wood stove chimney will extend straight up through the living quarters of your home , where the temperature is warm. The warm temperatures surrounding the chimney keep the flue gases warm , which helps create a strong draft.

Plus, the chimney exits near the roof peak. This eliminates the possibility of unwanted problems caused by outside structures. Besides installing an interior chimney, you should also make sure the chimney flue size matches the requirements of your stove.

For example, a flue that is too small can create too much draft , and a flue that is too large will have decreased pressure resulting in a reduction in draft. The stove manufacturer will have a recommendation for which size of chimney flue you should install for optimal performance.

Typically the flue collar on the stove will determine your chimney flue size. Limit the number of bends in the chimney by reducing excessive T's or elbows and try to avoid long horizontal runs in the chimney. Think of a chimney as a dryer vent. The more the dryer vent bends and zigzags, the more lint it collects inside the pipe. A chimney is the same way ; only the lint is actually creosote.

A straight, vertical path without restrictions will create a strong draft. Most wood stove manufacturers rate their equipment to accept only a few venting systems. That makes it less intimidating to choose from the wide variety of options available. However, there are several things to consider, ensuring the best functioning of your unit. Wood stove venting has two main categories:.

Air-cooled chimney systems use air for cooling. They have a space between the chimney walls to allow air from outside to move freely. Since air is not as good in insulation as solid materials, air-cooled chimney systems are usually big. Their design allows for at least 2 inches of airspace between each chimney wall layer. The height of the chimney, the size of the flue, smoke chamber construction, and other components work together to either ensure a strong draft or detract from it.

Contact our chimney professionals when you are ready to have a new and efficient wood-burning fireplace or wood stove installed in your home. You will be able to rest assured that the flue is the right size, the appliance will be safe to use, and it will operate correctly.

We Have Chimney Leaks! All Articles April Showers Bring…. Can Chimneys Get Repaired in the Winter? Do I Need Fireplace Doors? Does your Chimney System Need a Makeover? Wood Fireplaces: Which is best for you? Has My Chimney Had a Fire? How Does a Chimney Work? How Much Firewood is in a Cord? Is Chimney Cleaning Always Necessary? Is Chimney Sealant a Good Idea? The specifications for venting for each appliance will be spelled out in your owner's manual.

Direct vent units may be referred to as "top vent," "rear vent," or "slant-back. Many direct vent appliance manufacturers will offer specific horizontal or vertical venting kits for particular units. When looking into purchasing these kits, be sure to find out how much pipe you would be getting and if that would be enough to complete your system.

Stove pipe, also called a chimney connector, is not the same as a Class A chimney pipe, although these two are often confused with each other. Stove pipe is used for venting wood burning stoves and is only for use inside the home, or more specifically, inside the room where the stove is installed. Once the venting reaches the wall or ceiling, it must be converted to Class A chimney pipe.

Depending on which kind of stove pipe you use — single-wall or double-wall — you must also account for proper clearances from combustibles.

For example, a single wall stove pipe requires 18 inches of clearance from ceilings or walls. Double wall stove pipe, on the other hand, requires only 8 inches of clearance from the ceiling and 6 inches from a wall. Once these clearances are met, you must convert your stove pipe to Class A chimney pipe for proper venting of your stove. Many stove owners from years past may be surprised to know that stove pipe is never permitted to go through a ceiling or a wall, no matter how much clearance you can create.

Therefore, it is never safe to use only stove pipe for venting. This is simply a matter of the way these pipes are engineered.

If used outside, stove pipe will be unable to maintain high flue temperatures, causing potential creosote buildup and increased risk of a chimney fire.

Class A chimney pipe requires only two inches of clearance to combustibles because it is made to handle the highest temperatures for exhaust. This is why you must convert from stove pipe to class A chimney pipe when venting your wood burning stove. There are a couple of different ways to make the conversion from a wood stove pipe to a chimney pipe for proper venting.

These include through-the-ceiling or through-the-wall venting methods. Each installation calls for different components, depending on the transition point between the stove pipe and Class A chimney pipe. Through-the-ceiling — For venting systems that run vertically through a ceiling, you must have a ceiling support box or round ceiling support piece to use as your transition point from the stove pipe to the Class A chimney pipe. The stove pipe will connect to the bottom, and the Class A chimney pipe will attach to the other side, either running through the ceiling support box itself or an attic insulation shield in the case of round ceiling support.

From here, chimney pipe will pass through a pitched roof by use of roof flashing, or it can be built into a framed wooden chase, which must be topped off with a fabricated chase top flashing. Through-the-wall — For venting systems that run horizontally through a wall, you must have a thimble. A thimble is designed to allow Class A chimney pipe to pass through the wall, run into the room where your appliance is installed, and then connect to the stove pipe. Depending on what kind of stove pipe you use, the Class A chimney pipe must come into the room six inches for connecting to double-wall stove pipe or 18 inches for connecting to single-wall stove pipe.

Most wood burning stoves are top-vent models, meaning the flue collar will be on top of the unit. For any horizontal, through-the-wall venting system, you must have at least 12 inches of vertical rise from the top of the stove not including the flue collar itself or any elbows before connecting a degree elbow piece to turn toward the wall.

Some older wood burning stoves are rear vent models. These models require the use of a tee for cleanout purposes at the flue collar. Like top-vent models, they require a minimum of 12 inches of vertical rise before directing the vent pipe horizontally. Please see your owner's manual for more details.

There is one main difference between wood-burning and direct-vent stoves. Some direct-vent stoves are rear-vent models and able to vent horizontally from the flue collar to the wall.

Other direct-vent stoves are "slant-back" models, meaning the flue collar is positioned at a degree angle on the unit, allowing some versatility for vertical or horizontal venting without having to use a degree elbow.

For more information on venting direct-vent stoves, please see the section on direct-vent pipe. Type B gas pipe , also called "B-Vent" or "Natural Vent," is prefabricated, double-wall metal pipe used to vent gas appliances listed for use with Type B gas vent.

Type B pipe is becoming less prevalent for venting hearth products, but many furnaces and water heaters still use it. The biggest reason for the declining use of Type B vent pipes for hearth products is their lack of efficiency, especially compared to direct vent and vent-free units. However, there is still a market for B-Vent piping for fireplaces because of its economic viability, which makes it particularly appealing for contractors and builders.

Another advantage of Type B is that it is not typically susceptible to excessive draft problems, due in part to the draft hood that draws in excess air to moderate strong draft. Most B-Vent pipe has a one-inch clearance to combustibles. Type B pipe is never suitable to be used with wood-burning or coal-burning appliances.

Also, it should never be used as a free-standing exhaust pipe for high-temperature venting. Pellet vent pipe is used to vent pellet-burning or corn-burning stoves. These pipes are smaller in diameter than any other vent pipe, usually with a diameter of 3 or 4 inches. Double wall pellet pipe requires a 1-inch clearance to combustibles. And unlike stove pipe, pellet vent pipe does not require Class A chimney pipe for installation. In other words, you are not required to convert pellet vent pipe to Class A chimney pipe when passing through a wall or a ceiling.

Pellet pipe is used all the way from the pellet-burning or corn-burning appliance to the termination point. Similar to direct-vent systems, pellet venting can be terminated either vertically or horizontally. If terminating horizontally, the cap must be at least 6 inches from the outer wall of your home.

If terminating vertically, the cap must be at least 12 inches above the roof. If you are venting for a pellet-burning insert, however, your appliance will require a flex pipe to bypass the smoke shelf. At this point you would be able to convert to rigid chimney or pellet vent pipe with an adaptor.

Class A chimney pipes have their own specialized caps that fit right on top of the pipe at the point of termination above the roofline, commonly referred to as chimney caps. When terminating a Class A system, you must follow what is known as the "" rule or the "foot, 2-foot" rule. Please note that this code must be met with the foot radius, clear of any obstruction at the top of your pipe before your cap is installed. This rule is in place to ensure proper draft for your unit.

If you have any questions about whether your system meets code with regard to this requirement, feel free to call or email us , and we will be happy to help.

Type B systems can involve a multitude of distinct piping components, and the termination point is no different. B-Vent systems can only be terminated vertically, with several different kinds of caps available depending on your manufacturer's guidelines and requirements. See the chart below for help with measurements. While many stove pipe and direct vent pipe systems use degree and degree elbows, Class A chimney pipe systems do not allow for more than a degree elbow.

In fact, you'll need two elbows if offsetting Class A chimney pipe — an elbow to start the offset and another one to end the offset.

For this reason, most Class A chimney manufacturers only sell elbows in kits that have two elbows and an elbow strap for support. Also, only a limited amount of offset is permitted usually no more than just over 3 feet or less between the two elbows.

Using the two elbows to offset Class A chimney pipes optimizes your chimney's performance and protects against drafting and flow problems. When dealing with offsets with stove pipe and direct vent pipe, you can offset to go around an obstruction for up to nearly 60 inches for stove pipe and nearly 40 inches for the direct vent pipe.

Pellet Vent pipe, however, can be offset for almost 80 inches. These are approximations. Please consult the section pertaining to offsets in the owner's manual for your appliance and the pipe manufacturer's guidelines for offset allowance with each type of pipe.

We hope this guide has been helpful and informative. Remember, it cannot be stressed enough to consult your owner's manual above all else when considering how to vent your hearth appliance. Some local codes require you to use only the kind of pipe listed in your owner's manual for your unit. Always check with your local building code officials when designing a chimney system to ensure proper installation. If you have lost your owner's manual, please call or email us , and a member from our knowledgeable staff will be happy to see if we can locate one for your fireplace, stove, or insert.

He is a Master Hearth Professional, which means he is certified in all three hearth appliance fields — wood, gas and pellet. When not at work, he spends time with his wife, Lindsey, and his sons, Samuel and Eli, on their ranch enjoying their many animals. Completing projects around the ranch and spending quality time with his family are among his greatest joys. This will depend on the specific model. Some direct vent gas fireplaces can utilize a flexible vent pipe, but others cannot.

This information will be stated clearly in the installation manual. Can an existing masonry chimney with a clay flue liner be raised using a metal adapter and triple wall pipe to the required height? I bought the thimble to go thru the wall, but the wall width is much less than the thimble width. Is it acceptable to reduce the width of the thimble using a tin cutter to match the width of the wall? Can I vent a 80, BTU garage furnace flue 4" diameter, lp into an existing 8" wood burning stove flue single wall prior to going through the attic's class-A flue?

We do not recommend changing the diameter on your furnace.