I begin with the more common connection methods and situations.
You may already have got the message that I strongly suggest that you fit a chimney liner rather than connecting directly to a chimney.
If you are going to connect your flue pipe directly to your chimney please consult with your Building Control Officer.
You do not have to line your chimney with a chimney liner. Building regulations allow direct connection of flue pipe to chimney as long as there is no danger of the building catching fire and that the combustibles (smoke) are successfully taken away via the flue.
Danger of the building catching fire? See the page primarily aimed at “Distance to combustibles“. Essentially there should be nothing near to the stove or the flue that can catch fire. Main culprits are wooden fireplace beams but prepare to look for the unexpected. I recently discovered wooden “three by twos” inserted through two chimneys as part of a recent bathroom refurbishment! The offending wood was only discovered when our liner would not go down the chimney and we had to create a hole in the upstairs bedroom. Had we of not lined the chimney chances are that there would have been a fire.
Is the chimney suitable? Combustibles being taken away suitably (draft good enough)?
Let’s look at some of my scribblings:
Top hat connector
If you have a pot lined chimney then probably the easiest method of connection is to use what I call a “top hat” connector. This is a stainless steel flat sheet square with a tube sticking out from it. The square is screwed to the ceiling of the fireplace (Thunderbolts are great for this). Because the diameter of the pot flue will be more than the tube of the top hat then soot could build up on the top hat. Note the diagram shows that I have reached up inside the top hat and flaunched with mortar to provide a funnel so the soot falls into the stove rather than collecting anywhere (soot deposits can catch fire).
Update: I have fitted the top hat connectors without problems but have had a problem with one recently. I now recommend a sump adaptor.
Obviously the ceiling of your recess might not be nice and flat. Can you make it flat? Using non combustible materials?
In our next scribble there is a register plate fitted (galvanised metal minimum 2mm thick) with access doors to sweep and collect soot. A register plate MUST be very securely fitted (usually using “angle-iron” to hold it in place. The plate must be completely sealed to prevent smoke entering the room (you can reach in and feed mortar onto the corners to assist this).
This is not ideal. The void can cause turbulence and also cool the smoke so it does not rise up the chimney as it should.
I have to say though that it can and does work for some people. BUT you might have problems with the stove drawing properly. Note that just because an open fire worked perfectly in a chimney it does not follow that a modern wood burner will – 0pen fires waste copious amounts of heat up a chimney whereas modern wood burners, being more efficient, put less heat up a chimney; more heat is more draft.
How do you know if the stove is drawing correctly? Well you can just light the stove and see how it performs. You can warm the flue and perform a “Smoke Test 2”. You can measure “draft” using a professional guage (the stove manufacturer will provide the minimum and maximum draft at which the stove will perform well).
Image: Top hat connector
Costs correct as of April 2023:
Approx. costs if you have a chimney and fireplace ready to use: £750-£1,000 (save £500 by self-installing).
Approx. costs if you have a chimney but need the fireplace "opening up": £1,600-£2,200 (save £1200 by self-installing).
Approx. costs if you do not have a chimney and need a clip-together flue: Shed £475-£700. Bungalow £1500. 2-storey house £2500. Save £1,000-£1400 by self-installing.
Above figures include labour and materials but no appliance.
We, of course, advise you to purchase your stove and materials from Stovefitter's to ensure quality goods are installed (some installers use budget materials to increase margin). If you buy your stove from us (rather than your local small shop or installer) we have a lot more power when approaching manufacturer's with a warranty issue. Why is that? Because we buy many hundreds of stoves a year from these brands.
We do not fit stoves.
But we know a few who do!
Google: Hetas installers
Hetas are the trade body of registered UK installers.
Most installations will require that you slide a chimney liner down your chimney (flexible metal tube 5" or 6" in diameter). Do you have a narrow chimney and want to lessen the risk that a liner might not go down your chimney? Then make sure your chosen stove can use a 5" liner.
Must I line my chimney? Best read this article but most likely the answer is yes. Do I have to fit a chimney liner?
DEFRA-Exempt wood burning stoves with a 5″ collar can usually be fitted to a five inch liner rather than the usual 6″ minimum, making the installer's job much less stressful.
ALL OF THE 5KW STOVES WE SELL CAN BE FITTED TO A 5" CHIMNEY LINER.
I seriously suggest any self installer fits a 5" liner unless they know their chimney is large enough for a 6"!
What is the best chimney liner? Silvacore 904 (we sell it so of course we will say that ;-). What is the best chimney liner?
Will your stove require an air vent within the room (some stone walls are very difficult to drill)?
5kW or under and wood burning stoves often do not require an air vent (new builds always require an air vent).
What is the maximum output in kW of your "5kW" wood burning stove? The majority of manufacturers just specify the “nominal output” and this figure means very little in real life. The nominal is a figure the manufacturer chooses to sell the stove at - the stove is capable of reaching at least this output with one fuel load. Nominal means "capable of". But it is not the maximum.
Check out the size of the area where the logs will go (firebox size) as this varies enormously. The kW output is completely dependant on the amount of logs burning at any one time - more logs burning equals more heat. If you can fit three logs in stove A and just two logs in stove B then stove A will be capable of throwing out 33% more heat.
DO NOT TRUST MANUFACTURERS’ kW RATINGS as manufacturers specify what output they desire to sell the stove at and testing allows for much “playing with the figures”. This is why you can get very small 5kW stoves (e.g. Aga Little Wenlock) and very large 5kW stoves (e.g. DG Ivar 5 by Dik Geurts which is actually rated 5kW but has a MUCH larger firebox than the Ekol Crystal 5 by Ekol Stoves). A Crystal 5k might get to 5kW and not be capable of any higher whilst a DG Ivar, despite being rated at 5kW, can get to 8kW with a full fuel load.
Note that, over time, one might damage the internal firebricks of a stove by running at a higher load than the manufacturer's suggest. Firebricks are easily replaceable.
Will your wood burning stove fit in your recess WITH the required air gaps around it? This is obviously not an issue if your stove will be freestanding.
Air gaps to non-combustible materials (brick, stone etc.) are usually "as close as you like" legally but manufacturers will sometimes specify a recommendation. This recommendation is there to allow heat to escape from the recess into the room - so you get the heat benefit rather than the heat soaking into the building structure and being lost. If no gap to non-combustibles recommended then we suggest 50-100mm air gap left and right of stove, 50mm behind and 100mm above.
Choose your stove accordingly.
A stove must be DEFRA-Approved if you wish to burn wood in a smoke control area.
ALL OF THE STOVES WE SELL ARE DEFRA APPROVED FOR SMOKE CONTROL AREAS.
In simple terms if a stove has an efficiency rating of 70% then 30% of the heat from your logs goes up the chimney.
If a stove has an efficiency rating of 90% then only 10% goes up the chimney.
So think of this in terms of how many logs you have to chop/buy.
Example: A Saltfire Peanut 5 by Saltfire Stoves in Dorset has an efficiciency of 80%.
A tall chimney (6m or more) that is lined will be happy with an efficient stove.
Efficiency importance can be said to be overrated and anything between 75% and 85% is fine. Go much higher and performance can actually suffer (smoke in room when opening door to reload, blackening of glass).
