Chimney Liner BTU Calculator

Chimney Liner Size (Inches)	Estimated BTU Capacity
3-inch	20,000 – 30,000
4-inch	30,000 – 40,000
5-inch	50,000 – 60,000
6-inch	70,000 – 100,000
7-inch	100,000 – 150,000
8-inch	150,000 – 200,000

FAQs

How many Btus can a 5-inch chimney liner handle? A 5-inch chimney liner can typically handle around 50,000 to 60,000 Btus.

How do you calculate what size chimney liner you need? Chimney liner size is calculated based on the appliance’s Btu output. A common rule is to have a liner that can handle 1 inch of diameter for every 7,000 to 10,000 Btus.

What is the heat rating of a chimney liner? Chimney liner heat ratings vary, but they’re generally rated for the temperatures produced by the specific appliances they serve. Stainless steel liners are often rated between 1,200 to 2,100°F.

What size flue liner for gas fire? For gas fires, a common guideline is to use a flue liner that’s at least the same size as the flue outlet of the appliance.

How many Btus can a 4-inch liner handle? A 4-inch chimney liner can typically handle around 30,000 to 40,000 Btus.

What is the 321 rule for chimneys? The 321 rule suggests that a chimney liner should have three walls: an inner wall to protect against corrosion, a middle layer for insulation, and an outer wall for additional protection.

Does chimney liner size matter? Yes, chimney liner size matters as it ensures proper drafting, safety, and efficient operation of the appliance.

How far should a chimney liner stick out? A chimney liner should extend a few inches above the top of the chimney stack for optimal performance and draft.

What is the difference between a 316 and 904 chimney liner? 316 and 904 refer to different grades of stainless steel. 316 is suitable for most applications, while 904 is more corrosion-resistant and appropriate for aggressive flue gases.

What is the best flue liner for a chimney? The best flue liner depends on your specific needs and the type of fuel being burned. 316 stainless steel is commonly used and versatile.

How many years does a chimney liner last? A chimney liner can last around 15 to 20 years or more, depending on usage and maintenance.

Do I need insulation around my chimney liner? Insulation around the chimney liner improves draft and prevents condensation, enhancing safety and efficiency.

Do gas fires need a chimney liner? Gas fires often benefit from chimney liners to ensure proper drafting and prevent corrosion from moisture and acidic flue gases.

What size chimney liner do I need for my furnace? Furnace liner size depends on the furnace’s Btu output. Consult a professional for accurate sizing.

What kind of flue do I need for a gas fire? A gas fire requires a flue that matches the appliance’s flue outlet size and complies with local codes.

How do you calculate BTU for a gas line? Calculate the Btu requirement of all connected appliances and add them together to determine the total Btu needed for the gas line.

What size gas line do I need for 200,000 BTU? For 200,000 Btus, you might need a 1-inch or larger gas line, but consult a professional for accurate sizing.

How many BTU can a 3/4 gas line carry? A 3/4-inch gas line can generally carry around 60,000 to 70,000 Btus.

What is the 7 times rule for chimneys? The 7 times rule suggests that the chimney’s height should be at least 7 times the chimney’s horizontal distance from the nearest roof surface or structure.

What is the 2 and 10 chimney rule? The 2 and 10 chimney rule refers to maintaining a distance of at least 2 feet from a roof surface and 10 feet from a roof ridge or peak for safe chimney placement.

What does Class 1 or 2 chimney mean? Class 1 and Class 2 refer to different types of chimneys. Class 1 chimneys are suitable for all fuels, while Class 2 chimneys are designed specifically for gas-fired appliances.

How do I choose a chimney liner? Consider factors like appliance Btu output, flue size, fuel type, and local regulations when choosing a chimney liner.

Can you put a liner in an old chimney? Yes, a liner can often be installed in an old chimney to improve safety and efficiency.

Can you push a liner up a chimney? Yes, a liner can be pushed up a chimney using specialized tools and techniques.

Does a taller chimney draft better? A taller chimney can improve draft, but other factors like diameter and condition also play a role.

Should you sweep the chimney before installing a liner? Yes, it’s recommended to sweep the chimney before installing a liner to remove debris and ensure a clear path.

How often does a chimney liner need sweeping? Chimney liners should be swept annually to remove creosote buildup and maintain safety.

Can you use black stove pipe for a chimney liner? Black stove pipe is not suitable as a chimney liner; it’s intended for connecting stoves to chimneys.

Can you have a chimney fire with a stainless steel liner? Stainless steel liners reduce the risk of chimney fires, but proper maintenance is still essential.

Which is better 316L or 904L flue liner? 904L is more corrosion-resistant, making it better suited for aggressive flue gases, but 316L is suitable for most applications.

Do I need a stainless steel liner for my chimney? Stainless steel liners improve safety, draft, and efficiency, making them advisable for many applications.

Do I need a flexible flue liner? Flexible flue liners can adapt to existing chimneys and may be needed in certain installations.

What is the best grade of stainless steel for a chimney liner? 316L stainless steel is commonly used and suitable for most chimney liner applications.

What material is best for chimney liner? Stainless steel is the most common and recommended material for chimney liners due to its durability and resistance to heat and corrosion.

What happens if you don’t insulate a chimney liner? Without insulation, the liner can be prone to condensation buildup, which may damage the liner and affect draft.

Can I replace a chimney liner myself? Chimney liner installation can be complex. It’s recommended to have a professional handle replacement to ensure safety and compliance.

What holds a chimney liner in place? Chimney liners are often held in place by top plates and rain caps, and sometimes anchor points lower in the chimney.

Is it OK not to have a chimney liner? While some masonry chimneys might not require a liner, using one enhances safety, efficiency, and draft.

Should a chimney chase be insulated? Insulating a chimney chase can prevent condensation and improve energy efficiency.

Does smokeless coal ruin flue liners? Smokeless coal produces less creosote, but regular maintenance is still required to prevent buildup.

Can you use a gas chimney liner for a wood-burning stove? Gas chimney liners are not suitable for wood-burning stoves due to different requirements for heat and condensation.

What are the different types of chimney liners? Common types include stainless steel, aluminum, and clay tile liners. Each has its own advantages and applications.