Anybody have recent experience of this?

I remember in UK that was quite simple to do; basically you just bought a stove that was designed to fit into the square fireplace hole; no need to link a pipe to the existing chimney or anything else complicated.

No doubt in Switzerland it is more complicated and there are building regulations to worry about.

Currently I burn normal firewood (not pellets) in my fireplace from time to time, more for the visual comfort effect than to supplement the heating.
I know stoves are far more efficient at turning wood into heat so I wondered if there is a simple solution here.
I googled around but did not really get helpful results.

The fireplace is 70cm wide and 57cm high,

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It is naive to assume my posts are my own work

Not sure this will be a lot of help, but I just took out a freestanding 'fireplace' and replaced it with a small glass-fronted burner. I've re-used the existing flue although it's wider than the stove's outlet, so an adapter was required, and in talking to people at several DIY shops both in CH and France (where I bought the new poêle) I didn't come across any idea that there were lots of 'rules' to conform with, other than the stated techniques requirements of the new unit.

These did include lots of info about pressure gradients, but it seemed that going from a smaller outlet into a bigger flue, assuming it was correctly designed in the first place, would always give a better 'draw' than needed.

So piping one into an existing chimney should be OK in principle, but I think you'd need to fit a flue from the new stove at least some way up the chimney - just letting smoke out of the top below the existing fireplace sounds like a very bad idea, if that's what you're thinking of. Certainly in my research I never came across anything that was designed to do that.

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Introduce yourself!

It seemed to me in my simple way that when I burn wood in my fireplace the smoke goes up the chimney OK so if I would burn the same wood in a stove then why would the smoke from the stove not do the same?
Probably there is some obvious reason that I overlooked?
If it is a convection type stove that takes air from the room circulates it around the oven outside and back into the room then clearly the smoke must be contained?

Not sure about 'obvious' reason, but clearly the fumes coming out of the top of the stove will have different dynamics compared with those from an open fire. A lot of the heat may have been diffused into the metal of the stove, particularly when you first light it, and the upward flow will have been significantly modified, both by the internals of the stove immediately above the fire itself and by being channeled into the outlet pipe.

So I wouldn't be surprised if the smoke behaved differently, which may or may not include less upwards momentum, once released, as it's then being allowed to expand into the larger space and with less heat in it may creap around the edges rather than directly up the chimney.

This is all based on guesswork, mind, or at best a very limited knowledge of gas flow dynamics and some logical thought, so I'd gladly learn that I'm mistaken, and it's not at all unlikely that I am. But I would be very cautious.

Incidentally, the reason I replaced the older, much bigger, unit sooner rather than later was that it was impossible to use without significant smoke escaping into the room, and watching the way the smoke flowed in all sorts of unexpected ways has had me giving some thought to this subject.

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Introduce yourself!

Stoves are pretty much the same efficiency in terms of heat conversion, they're just a lot better at getting the heat into the home because the sides and chimney are exposed and act as radiators instead of just heating up a chimney which is probably insulated from the home and/or on an outside wall.

You need to get someone who knows what they are doing to help.

In Germany, for example, there are quite strict rules regarding stoves and fires.
In certain circumstances, one is not allowed to have the kitchen extractor fan on at the same time as the pressure difference could draw the fires exhaust fumes into the house.


And, carbon monoxide has no smell and is invisible and kills many people each year (a Swiss couple dies a couple of weeks ago).

I'll look to find a picture of how ours is plumbed into the fireplace (pipe enters the chimney about 1/2m above the top of the fireplace opening.

Tom

I thin you may have to have a stainless liner fitted into your existing flue.

The problem is the door in the flue: you can't get a good connection to the underside of it, so you can't be sure that the CO leaves the house.

If you plumb into the chimney above the door, then the door needs sealing off.

Call the place that sweeps your chimney, they'll know best.

Chances are also that you would need any new installation to be inspected by the cantonal authorities. If you get a local professional to install it, the inspection process becomes a piece of cake. If you DIY, you'd have to make absolutely sure you know every single regulation and comply to the letter

I don't know about the Gemeinde requirements - but the houses here are so hermetically sealed (unlike draughty English houses) that sometimes there is a need to equalise the pressure by opening an external window when you close the chimney door to avoid smoke from the top of the flue escaping into the lounge. It even mentions the issue in the owners manual from the stove company....

Same issue as Tom1234 mentioned above re extractor fans etc....

No problem with ventilation here, the houses are built to get the heat out as fast as possible and they are very efficient at it. Works great in summer, when it´s around 50 outside, the inside is a cool 40-odd, however in winter when it´s really cold, let´s say 15 to 20 degrees outside, the unheated flats and houses are at a nipple-freezing 10 to 15.

I recall that many people have said the same about DIY electrical work, but so far no-one had been able to provide a source to support the idea. It's clear that building/instalation regulations exist, and that an official inspection can be requested (one was done by the vendor of the chalet we've just bought, for example, and some remedial work performed by a certified professional) but it seems that there's no absolute requirement for a bricoleur to do so.

So is it different for stove installations? As I commented above, the availability of fixtures and fittings from Swiss DIY shops indicates otherwise and I've seen and heard nothing (apart from your post) to suggest that I need to get my new installation independantly inspected. So I haven't felt the need, so far, to do what you suggest (in red) above. Please feel free to enlighten me, as I would really like to know if I'm wrong.

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Introduce yourself!

If you already have a chimney for an open fire that generally draws OK, it's very unlikely you would have a problem with air supply - an open chimney is much less efficient in drawing than a stove because it tends to suck in a load of cold air from above the fire, whereas a stove pushes all the air through the fire itself.

The CO problem is more that you can close down the air supply to a stove, thus causing CO if there is too much wood left - and simultaneously stopping the chimney drawing well. This has been covered in stove manuals I've seen.

Obviously the risk is worse if the chimney isn't well sealed.

It would appear that you do in fact need a permit to install or modify a system.

(http://www.feusuisse.ch/de/vorschrif...#anchor_VPYYGY)

And also that the Kt. Gebaudeversicherung has a finger in the pie too.
(https://www.gvzg.ch/files/Bewilligun...d-Cheminee.pdf)

This is a safety issue, a potential hazard. You definitely want to contact the Feuerpolizei.

What you have in mind may be an utter non-issue (it may well be), but if not and disaster strikes you're in a world of pain if yod didn't contact build according to regulations.

This, absoltuely.

In a previous property we had a free standing stove in the living room and because there was no chimney in that room, there was a long pipe of enameled metal that went up the wall, around a corner and through another wall to gain access to the nearest serviceable chimney flu which was in the adjacent room. At one point smoke stains started appearing on tbe wall where the pipe went through the wall, and it smelt smokey. We checked and found the pipe elements had moved and there was a small gap between two sections. It was easy to fix, but it shows smoke does leak out of flues.

Smoke stains may just be annoying and ugly, but carbon monoxide is posionous.

I don't know about thermal efficiency, but modern wood burning stoves have lower particulate emissions.

I also guess the efficiency is actually higher. When I clean out my fireplace there are lots of small bits of charcoal in the ash and bigger bits left on the grate. My stove leaves only very fine ash of a notably lighter colour, suggesting (to me at least) that the carbon content is lower.

Less carbon in the ash means less unburnt fuel being thrown away.

Yes, as I accepted, there are lots of rules and regulations concerning building work.

Nothing I could see on that page (once I selected it in a civilised language) suggests in any way that these would apply to DIY work on existing installations. I'm not saying that they would not, but quoting a page about building regulations that apply to new construction work doesn't move the question forward at all.

Sorry to be pedantic, but:

I read that as "Construction or modification".

You can buy a scalpel from a hobby shop. It doesn't mean you're permitted to perform surgical operations on friends and family.