I was inspired to write this post by an installer who popped in to buy some flue components last week, who grumbled, “I wish people wouldn’t keep ordering Clearview stoves; it’s so much easier to fit a 5” liner than a 6” one.”
This particular installer is famously agnostic about what he fits, claiming that he lets the customer choose the stove, and whatever they choose, he’ll fit it. But, as I understand it, the guidance he does give is that they should choose a DEFRA-approved stove, which, as coincidence has it, you are allowed to fit with a 5” flue (as long as it has a 5" flue outlet).
Notwithstanding HETAS and Building Regulations guidance that you should, where possible, fit a minimum 6” diameter flue regardless (but that 5” is allowed as a default if a 6” liner won’t fit in the chimney, for instance), this innocent-sounding advice means that the installer can get away with using easier-to-fit, and marginally cheaper, 5” flue.
There is nothing wrong with DEFRA-approved stoves per se; there are good ones and there are bad ones, just as there are good and bad stoves generally, but the DEFRA approval simply means that the stove in question is approved for use in smoke-control zones, which are usually found in dense conurbations. The only city centre we currently have locally which requires DEFRA stoves to be fitted is central Southampton.
DEFRA as a designation will shortly, in any case, be superseded by Ecodesign, which incorporates most of the features of DEFRA stoves, but with even higher efficiencies. Most of the stoves we sell are already Ecodesign-compliant - https://www.hetas.co.uk/ecodesign-compliant-stoves/ , and many also meet independent Clearskies criteria - https://www.clearskiesmark.org/ - the latest scheme from the woodburning industry itself.
Needless to say, unless you do actually live in a smoke-control zone, in which case it is vitally important to meet the prevailing relevant legislation, you can discard the DEFRA criterion when choosing a stove. What is most important is that a stove is clean-burning, solidly-built, controllable and from a manufacturer with a good pedigree (as you will be needing spare parts decades into the future, and don’t want to discover after five years that they’re no longer manufactured). Additional considerations will be choosing the right size stove to heat the required area, getting one that will fit where you want it (taking account of distance-to-combustibles), reconciling the flue draught requirement of your stove with the attainable chimney height, and of course, finding something that you consider pleasing to the eye.
It can be frustrating for independent stove fitters to try to persuade customers of the benefits of a provably superior stove over one they have found online or advertised in a magazine, and if the customer chooses the stove, it also absolves him (it’s usually a him) of the responsibility for it working properly and being serviceable in the future. Being too insistent can cost them the job, not to mention the disagreeableness of disagreeing in the first place! So it can pay to be sceptical of supposedly disinterested advice; as in most things, but especially with stoves (as most people only ever fit one or two in a lifetime), it pays to do your research and be fully-informed before you commit.
We’re always on the end of the phone if you have any questions, and do our best to offer professional, informed advice.
(As a post-script, it's noteworthy that Clearview built the first-ever smoke-control approved stove (1993), at a time when nobody believed it was possible. Just for the record! https://www.clearviewstoves.com/clearview-smoke-co... )