If you have an existing chimney that was built to general building regulations and is structurally sound and gas tight you don’t have to line the flue as long as it passes a ‘pressure test’. However, if you are fitting a closed appliance such as a wood burning stove we advise that you do line the chimney for performance purposes.
A closed appliance (stove) holds the heat inside much longer, making it highly efficient, but this can have a detrimental affect on the flue.
A chimney requires greater performance to pull the air required through a stove compared to an open fire and this increased draught can be achieved by keeping the flue gasses contained in a similar shape and form all the way to the top of the chimney. A liner does this and it also protects the chimney if the gasses cool to the point of condensation which when combined with the products of combustion can be very corrosive and damaging to the flue.
It’s worth remembering that all products vary in quality and that any warranties or guarantees are usually subject strict terms and conditions. We estimate that fewer than 10% of people would have a valid warranty/guarantee as most manufacturers require product registration, annual chimney sweeping by a registered sweep and dated receipts for all maintenance work.
As with most things you buy, go for quality products, listen to advice, burn good fuel and your liner will last a long time!
