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What Is a Triple Wall Flue?

What Is a Triple Wall Flue?

When it comes to installing a log burner in your home, you’ll have a number of options for the flue system. In many instances a single or twin wall flue will be sufficient. But, sometimes, you’ll need to use a triple wall flue. To find out more about triple wall flues, and when they should be used, keep reading…

What is a triple wall flue?

Let’s begin with a definition. What exactly is a triple wall flue?

Well, as the name suggests, a triple wall flue is a three-walled insulated flue that is ideal for use with the latest generation of high-efficiency wood burning stoves.

The exact construction of a triple wall flue varies depending on the manufacturer, but here at Trade Price Flues our triple wall flues begin with a flue liner within a flue liner. The space between these two liners is filled by 30mm of mineral wool insulation. These two liners are then placed in a third, larger and thicker outer liner. The space between the two inner liners and the third outer liner is left empty to create an air gap.

This type of triple wall flue construction offers the best of both worlds - you benefit from both solid-packed insulation and air cooling in a single flue construction.

This means that the flue doesn’t become hot to the touch and will protect any nearby walls or combustible materials from heat damage.

What’s the difference between twin wall and triple wall flues?

Now that we’ve defined exactly what a triple wall flue is, let’s take a look at another question we commonly receive here at Trade Price Flues.

Is there much of a difference between a twin wall and a triple wall flue?

The answer is yes!

Apart from the obvious - that a triple wall flue features one more flue liner than a twin wall flue, there are a number of other important differences between the two types of flue:

> Mineral wool insulation - this is the most obvious difference between the two types of flue. With mineral wool insulation in place, triple wall flues are exceptionally well insulated. This is useful if you’ll be using the flue with a particularly hot burning stove.

> Safety - many installers consider triple wall flues to be the safest option. This is because the high-degree of insulation they offer minimises the risk of fire or heat damage within the home.

> Cost - although it’s only very marginal, triple wall flues tend to be slightly more expensive than twin wall flues because of their additional material and construction requirements.

With those differences in mind, you may be wondering if there is a particular method for deciding which type of flue you should use.

In our experience, the way to decide between twin and triple wall flues is to consider the scenario in which it will be used.

For example if you’re installing a log burner in an existing class 1 chimney then it’s generally easier and more suitable to use a twin wall flue. Likewise, if you’re installing a freestanding stove and need to ‘create’ a chimney for it, then a twin wall flue system will be suitable.

But, if you’re going to be installing a log burner in an environment where the insulation of the flue is particularly important (such as a conservatory), then we would recommend using a triple wall flue.

Additionally, triple wall flues tend to be airtight, which makes them ideal for scenarios in which you are attempting to achieve the maximum energy efficiency from a log burner. Because no air is lost via the flue, you can create an incredibly efficient ‘draw’ through the log burner.

Note - in short, there’s no hard and fast rule as to when you should use a twin or triple wall flue. If you’re unsure what type of flue you should use for your project, speak to a qualified heating engineer or stove installer.

What are the benefits of using a triple wall flue?

There are several benefits to using a triple wall flue system with your log burner, the most important of which being improved log burner performance.

A triple wall flue can significantly improve log burner performance by:

> Ensuring that smoke and other combustibles remain as hot as possible until they reach the top of the flue. This prevents the smoke from cooling and falling back down into the log burner, thus disrupting its operation.

> Reducing chimney downdraft issues. As our recent blog explains, chimney downdraft can have a detrimental impact upon the performance of a log burner. However, because a triple wall flue maintains the temperature of smoke and combustibles right up until the point they leave the flue, it can drastically reduce or even eliminate chimney downdraft issues.

> Improving the log burner’s draw. Log burners and their flue systems work on negative pressure. Air is drawn into the log burner’s air intakes, into the fire and then up and out of the flue. A triple wall flue is particularly good at maintaining this draw because of its high levels of insulation.

> Providing a closed and air tight combustion system. Triple wall flues feature an airtight construction meaning that they not only prevent pesky leaks of smoke, but also radically improve the efficiency of the log burner. Their airtight construction also makes them perfect for use in airtight homes where air permeability is an important issue.

Where to buy a triple wall flue

If you’ve decided that you need to install a triple wall flue, then it’s important that you purchase a flue which has been manufactured by a quality, reputable manufacturer.

Here at Trade Price Flues, you’ll find the very best triple wall flues. Not only do we offer a range of payment options, but we also offer free delivery when you spend over £150.

Shop triple wall flues at Trade Price Flues now

For more chimney and flue advice, read the Trade Price Flues blog

What Is a Twin Wall Flue System? | What Twin Wall Flue Regulations Are There? | What Different Types of Chimneys Are There?

23rd Feb 2022 Trade Price Flues

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