The chimney is the engine of your stove. If you don’t get your chimney right your stove will not perform as it was intended.

The chimney – or its draught to be more precise – is the most important factor in ensuring your stove works well. The smoke produced by the combustion of the wood – very hot and therefore very light – has a natural propensity to rise.

The flue must allow it to disperse.

What makes a good chimney ?

It must create sufficient but not excessive draught for the stove to which it is connected.

And what is needed to create this draught ?

  • sufficient height,
  • a chimney that is as vertical and straight as possible,
  • a smooth surface that does not prevent the dispersal of smoke,
  • an appropriate size in cross section – preferably round rather than square – and never less than the diameter of the stove’s smoke outlet,
  • a chimney that has a good cover, which ensures a sufficient draught regardless of the direction and speed of the wind. The dimensions of the chimney are determined by your supplier.*

At Ebben & Yorke we strongly advise all our clients to have their chimney lined prior to the appliance being installed by a competent HETAS-approved person.

The benefits of lining the chimney are extensive, and we believe the following advice from Clearview Stoves best sums up why we believe you should line your chimney:

“A chimney is a passage from the place of combustion to the outside world. Warm flue gases should rise through this passage to the point of exit. For a chimney to operate satisfactorily it should be smooth, warm and as straight as possible. If a chimney is irregular and rough, or cold and damp, flue gases will move slowly. Cooler gases will mean inadequate chimney suction and poor flue gas speed.

We always advocate flue lining where possible for the following reasons:

A flue liner will substantially decrease your chimney volume. Consequently, higher temperatures will be maintained and flue gases will travel faster, generating a greater and more consistent draft. When possible, flue liners should be insulated, increasing flue temperature. A warm flue will collect less deposit, cleaning will be much easier and condensation should not occur in the flue. It is possible to clean a lined flue well, leaving the liner almost as clean as new. It is rarely possible to remove all deposits that accumulate in unlined flues as there are always holes and corners a brush does not reach.

The combination of a Clearview clean burning stove and a warm flue liner should mean chimney fires are a thing of the past. Chimney fires are a common and frightening occurrence in an unlined chimney and may cause substantial damage.

A well installed stove should emit no smoke or fumes to the room. If a flue is damp and cold it will produce a poor draft, this poor draft may reduce further during slow burn periods as the flue cools. Chimneys are usually in much better condition externally than internally. Many years of sulphur attack may have eaten half way through brickwork and mortar. Internal feathers dividing one flue from another may have perforated or collapsed allowing flue gas to pass into redundant, uncleaned flues.

Air is also an important consideration to optimum performance of your stove.

The combustion of wood consumes air (8 m³ of air is required to burn 1 kg of wood). In older houses, air gets in under the doors and frames. In modern houses, which are more airtight, an outside air inlet is required. This should be as close to the stove as possible.

Other systems that require a lot of air – such as a cooker hood or ventilation system – which can affect the operation of the stove, must also be taken into account. These could affect the operation of the stove with the risk of the fire going out or backdraughts of smoke into the house.

Sources: Stuv / Clearview Stoves