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What is the Best Location to Install a Chimney System and Why is it so?

We often meet customers on a regular basis who have plenty of concerns regarding the installation and maintenance of the chimney system. Many customers are worried about the performance of the wood-burning fireplaces because of the chimney. It is extremely crucial to properly select a chimney and then effectively execute its installation and in most cases this doesn’t happen in the way it should.

We cannot stress the importance of having a clean and functional chimney. A chimney is responsible for venting out the smoke and gases out of your home, keeping both your home and your family safe. Thus, you need to install a chimney system in the right location and ensure that it is good working condition all the time.

A dysfunctional chimney could put you in serious risks of potential fire threats. So, we have tried to enlist some crucial things about chimney installation to help you out!

How to Choose a Chimney

The quality of the fireplace chimney should never be compromised. A poor-quality chimney could experience leakage or any other form of damage, putting your home under the risk of a fire. For the fireplace to function properly, you must choose a chimney that offers great services under all circumstances. There are two primary factors that need to be matched:

  1. Size of the Chimney – The first thing to check is that the size of the chimney flue, or the hole through which the gasses flow, matches the size of the fireplace or stove outlet. Bigger flues are never recommended when it comes to a chimney. However, in certain cases, smaller flues might work. Hence, it is advisable to always get professional advice before selecting a chimney.
  2. Insulated or Uninsulated – High-performance fireplaces and stoves require chimneys that offer high-performance and have insulation. The insulation helps the chimney draft which removes the smoke & gasses. Uninsulated chimneys are suitable only for open,decorative fireplaces. For advanced fireplaces and stoves, however, a specialized or a high-performance chimney is a must.

Apart from the above two key points, the height of the chimney should also be taken into consideration. The chimney should extend 3’ out of the roofline and be 2’ higher than any obstacle within 10’ horizontally, for specific cases like cottages with shallow roofs. Remember, a good chimney is one that has the following attributes:

  1. Is strong enough to protect the structure of the house from the hot gasses it conducts.
  2. Is able to withstand the high temperatures of the smoke & gas.
  3. Conserves the heat from the flue gas to produce a strong draft.
  4. Can resist corrosion from the gases on the inside and can withstand the effects of the weather on the outside.
  5. Supports sealing for prevention of any leakage.

Now that we have established the selection procedure for a chimney, let us look at the most crucial phase – its installation.

The Best Location to Install the Chimney

The best place to install a chimney is inside the house envelope.

No, the exterior of the house or chimney pipes running against the outside walls of the house is not a great installation idea! Rather, it is the biggest mistake you can make when installing the chimney. Let us discuss how the location of installing the chimney will affect its performance:

When chimneys are installed against an outside wall, it allows the cold air and foul odors from the external environment to leak into the house when the fireplace is not in use. The accumulation of these gases and dust results in excessive smoking when the fireplace is lit. Here is why it happens –

Stack Effect

When the weather is cold outside, the warm air being dense rises up. This is called stack effect. Due to this, the lower part of the house experiences a slightly low-pressure area while the higher parts of the house are characterized by high pressure. Separating these two zones, a neutral pressure zone is created between them. When the fireplace or stove is not in use, the outside chimney, being exposed to cold weather fills up with cold air. The house then acts as a chimney, which is more efficient than the actual chimney and sucks this cold and smelly air down the chimney flue.


However, if you install the chimney within the house envelope, you can prevent this from happening. When the chimney is installed inside, the temperature of the air in the chimney does not drop below the room temperature, as it is surrounded by warmth. Now, the neutral pressure zone in the chimney is higher than the neutral pressure zone in the house, disabling the stack effect and causing an upward movement of air through the chimney.

When the chimney is inside the house, the warmth inside the house keeps it warm, always making a draft. The draft created is greater than the stack effect of the house, creating a low-pressure zone at the fireplace opening. This means that when you light a fire, it will ignite faster and there will be no smoking.

Flow changes and Creosote Build-up

Another thing that happens with chimneys running outside the house is a change of flow. When the chimney cools, it produces cold backdrafts. If your fires goes out or really low then the chimney reverses and sends smoke into your room, which introduces more than two changes of 90 degrees in the flow direction. This change in the direction hinders the performance of the chimney and the fireplace.

Again, a chimney running inside the house produces a stronger draft as compared to the chimneys located outside the house. A stronger draft not only means better performance but also means that the chimney will accumulate lesser creosote deposits. Lesser accumulation of creosote will further make it safer, and require less cleaning and maintenance. So, save yourself all the trouble and grief and wisely install your chimney within the house envelope.

Also, when locating the chimney, you should always try to place the hearth in the heart of the home. Do not have it against a wall. This will mean that the chimney exits your house at the peak of the roof. Thus, enjoy excellent performance that is not affected by the cold winds and temperatures.

Final Thoughts:

Since there are so many things to weigh and consider to ensure a safe and functional chimney. It is best advised that one should always consult a professional. You can also get the fireplace and chimney installed from a professional too.

We, at The Original Flame, are always happy to guide our customers through the A-Z of fireplaces and chimneys. We also offer professional installations by certified technicians. So, feel free to drop by at our store for your fireplace queries!

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