Are there any disadvantages to installing a flue liner?
I was told first that it will make the stove more efficient. Then I was told that there was no guarantee that it would work. Now I am told that it will make it harder to clean the chimney (of our bungalow). I don't know whether to proceed and get it installed now or not.
It will not make the stove more efficient, however, it is a MUST for safety reasons and definitely install one for the following reasons:
1. The integrity of a clay liner cannot be guaranteed whilst the flexible stainless steel liner can be. Just ensure the chimney is properly swept before the flexible liner is installed. Hardened soot can damage the new liner during installation.
2. Should a blockage ever ocur within the stainless steel liner, flue gas emissions will not enter the property through the liner. A clay liner is pourous and therefore a blocked flue can leak carbon monoxide through the liner, then through the blockwork and into the property. A recent case in Northern Ireland last year highlighted this danger, when a couple died in their bed from a blocked clay flue liner, albeit from an oil fired boiler with a clay flue liner. A bird's nest was the culprit. The boiler had just been serviced by a non-registered/non-trained engineer and the deaths would have been avoided if he had noticed the issues. If he had carried out a flue gas analysis, the blocked flue would have been obvious from the readings and the relevant action could have been taken.
3. Ensure there is a cowl fitted externally to stop birds nesting. H cowls are best as they eliminate down-draughts and excessive draughts.
4. It will not make the chimney harder to sweep. Any decent chimney sweep will be well used to cleaning chimneys with flexible flue liners.
5. Finally, ensure that you have non-closable vents installed in the room with the stove and preferably close to the stove. They should be sized according to the kW output of the stove. There should also be a minimum of 2 vents, one high and one low.
I would also like to re-iterate the importance of flexible flue liners for the above safety reasons. The amount of stoves and oil boilers with flues entering clay liners with no cowls is rampant. It is also a flue that is rarely swept and poses an extremely dangerous carbon monoxide risk of poisoning. It only takes a partially blocked flue to cause problems.