Stoves v Fires

[Sonyaclegg]

I've had two gentlemen come to the house to quote for work to the 19 chimneys. I would like 17 positions closed with cover/register plate. So far so good.

I would like a huge roaring fire going in the formal lounge of a winters evening. It's a huge room with an enormous ingelnook fireplace under a segmented stone arch. The two chaps basically said the same thing; there would be little heat as it would all go up the chimney and smoke can come into the room. I understand that. They both advised fitting a Dovre stove with a large canopy.

I have never owned a house with a fire/stove. I understand stoves more than open fires but as open fires were going for hundreds of years before gas, surely I can have a couple!?

Where they advise I can have an open fire, in the smaller rooms, they advise making a bespoke canopy to fit above it to take the smoke away.

Can I not fit an insert into the fireplace void that is the grate and the canopy all in one. Forgive me as I don't know what they are called but some of you have those.

Please can you give me the benefit of your collective experience in stove/open fire operation. I'm keen to have an open fire somewhere but not if I put the family at risk of carbon monoxide dangers.

Many thanks, Sonya

 

[Sonyaclegg]

Next question. If I use a fireplace insert with the fireplace, can I fit it myself or do I have to have a Hetas approved fitter? Can we use the chimney as it was originally used?

I feel that we can as long as the chimney is sound. I am left with the impression that the stove chaps had an agenda....stoves! £2,000 for a stove. £200 for an insert and fitting. Mmmmm

 

[MdB]

What is the cross sectional area of the chimney (narrowest point)? What are the dimensions of your fireplace?

The first should be greater than 15% of the second. Otherwise a hood or other method for reducing the effective fireplace opening is needed.

 

[Sonyaclegg]

Do I need to measure the opening of the fireplace and then the narrowest point up the chimney?

 

[88v8]

Light a small fire in the fireplace, see if it smokes. It may smoke in some wind conditions, not others, repeat the process several times on different days. For this purpose you can light the (wood) fire on the hearth stone, you don't have to have a grate.

Many open fires smoke, especially when first lit and the chimney is cold, because the fire opening is too big in relation to the chimney. If the cross-sectional area of the opening is more than eight times the flue, it will smoke. Six times is ideal. Your 'huge' inglenook may have an equally huge flue, in which case it might be OK, stick your head and a tape measure up there.
The only way to be sure, however, is to to light a fire.

In the final analysis a bit of smoke never hurt anyone, and if it only smokes some days, or when it's just lit, you may feel you can live with that. But the smell is not pleasant.... We have two stoves, and they're nice enough, but it's not the same as an open fire. I took out an open fire (70s period repro but it looked fine) as even the PO admitted it smoked, and we had an intermittently smoking fireplace I never could fix in our previous house and I didn't want to repeat the experience.

I presume the room will have good ventilation? I'm not fussing about carbon monoxide, it's just the practical aspect that without a good air supply - 'draughty' windows etc - the fire will not - cannot - burn well, and will more likely smoke.

Your 17 closed fireplaces, a ventilation grate of course....

£2,000 installed, for a good stove? Pretty cheap, in my limited experience. Not familiar with Dovre, I see they make some traditional-looking models. Would highly recommend Clearview, (pic below) easy to light, excellent controls, economic, can be left unsupervised for long periods. Although their picture-window door is not really to my taste, I have to say.
We also have a new Esse. Compared to the Clearview, it's a POS. Hard to light, the controls are off/on, gobbles wood. Excellent pedigree, looked good in the showroom, huh.

I believe you don't need a HETAS fitter for a canopy, only for a stove & flue liner. Someone will confirm/amend, I'm sure.

Ivor

 

[stephenh]

Sonya - look up 'Rumford fireplace' on the internet, Wikipedia is a start.

A book that might help -
http://www.abebooks.co.uk/servlet/SearchResults?bt.x=0&bt.y=0&kn=fireplace&sts=t&tn=rumford

'Chimneys in old buildings ' by SPAB is well worth getting, if it is still in print.

Large fireplaces = large amounts of air up the flue causing massive draughts in large rooms / fireplaces. This is mostly stopped by Count Rumfords 4" 'throat' and can be further reduced by an under floor air vent from the outside coming up just in front of the fire with a sliding vent in the floor.




Something like this might help ?

 

[Sonyaclegg]

Thanks all.

The Dovre installed was from £3750. Worth it as it is stunning.

I'm off to measure and will report back soon

 

[88v8]

Do I need to measure the opening of the fireplace and then the narrowest point up the chimney?

The opening yes. As to the flue, sorry I can't recall the age of your building, but by Victorian times flues were of pretty uniform cross-section, that is to say after the initial gather, the flue was a uniform 9" or 12" or whatever was appropriate to the size of the fireplace. If that's the case, that's what you measure.

However, in earlier times such as our cottage, the flue might gradually taper all the way up, so measuring the cross-section becomes meaningless.
It's for that reason I say, light a fire.

Yes, a lot of warm air will rush up the chimney, yes an open fire is inefficient, but if you wanted efficiency you wouldn't have bought the house in the first place, I guess.

I'd forgotten about the Count. If you have a time machine, you could go back a few months to your constructional phase and summon him.

Ivor

 

[Lime]

Several decades have past since I lived with open fires.
They were enjoyable and satisfying for the most part except that they gobbled fuel and didn't heat the house.

Then I had a common-or-garden Parkray fitted.
Compared to an open fire, an enclosed fire is rather a disappointment but it has many benefits; some control over fuel consumption and no wasted heat roaring up the chimney are but two.
An enclosed fire also heats the house rather than a warm-to-baking semicircle around the hearth.

On a nostalgic note (and faced with ever increasing gas bills) I lit some open fires (ordinary Edwardian fireplaces) for Christmas two years ago.
The fun didn't last long, well for about an hour actually.
I discovered that my life had changed over the years wherein I now expect to live in a warm house rather than sit in a cold draught as all the warm expensive house air (from the gas heating) is sucked up the chimney.
I'd forgotten the mess of dust open fires create.
I'd forgotten that a fire is a "responsibility".
I found myself sitting in the room with the fire when I wanted to be somewhere else so as to not waste the heat what little there was of it.

I don't have open fires any more.

I still daydream of having a stove installed in our parlour but thought of the mess traipsed in and out from carrying the coal/wood and the ashpan puts me off.

 

[Penners]

Sonya - compared with the scientific responses that you've had above, I can only add a few inexpert comments, based on personal experience.

There are few things as unpredictable as an open fire in a period fireplace. The only real way to tell if the fire will be successful and satisfactory, in my view, is to try it. And there's no point in just lighting a small test fire for a few minutes - that won't give you a true picture. You need to get a really good fire going for several hours. This will thoroughly dry out the chimney and blast out any cold air "plug" that might exist. Once the fire is going really well, you can also get a subjective view of how warm and comfortable it makes the room feel.

For this experiment there's no need to buy anything - grate, fireback, etc. - just get the fire going well on the base of the hearth and feed it with dry logs until it's roaring away nicely.

This will give you a fair idea of how your open fire will perform. It's as close as you can reasonably get to a real-life simulation, although it doesn't allow for such vagaries as a change of wind direction.

If you decide that an open fire doesn't seem to be satisfactory, then a woodburning stove is, in my view, the very best alternative. In fact, I would opt for a stove rather than an open fire every time. It's more controllable, gives off heat to the room much more efficiently, and of course if you want an open fire you simply open the doors!

One other small point: when you block off all those redundant chimneys, do be sure that you make provision for good air circulation within each chimney stack. If you seal the thing up completely you create an excellent environment for damp and rot to permeate.

 

[Flyfisher]

There's no reason why an open fire shouldn't work with a large chimney, as long as it has the appropriate canopy arrangement and a suitably sized 'throat' into the chimney space. We have such an arrangement and it works well in terms of draw.

However, there's no doubting the lower efficiency of an open fire. In my experience open fires really only work well (as well as they can) with coal, because they rely mainly on the radiant heat into the room while most of the convection heat is lost up the chimney. Coal will burn hotter and for longer and will radiate far more heat into the room than an open wood fire.

I entirely agree with the above suggestions about testing your chimneys with a real fire if you are considering open fires. I wouldn't even bother with smoke pellets because the air inside a cold chimney (especially a large one) can be difficult to get moving and might give a false impression if the trickle of smoke escapes into the room. A good fire is really the best test. It will also give you an idea of how much coal (or wood) will be needed to heat the room, and how long it will take.

It can be a dilemma though because an open fire is often the most appropriate 'period' solution and a woodstove, albeit more efficient, can look somewhat out of place in a formal room. For this reason, we're planning to stick with our open fire in the formal rooms but have wood burning stoves in the less formal rooms. At least we'll have the option to change our minds later if we decide that the open fires are really not the answer. but we don't have to deal with 19 chimneys! I'd imagine that number of open fires would require a full time maid scurrying around with buckets of coal all day just to keep them all alight! :wink:

 

[MdB]

In the final analysis a bit of smoke never hurt anyone

Tell that to people with lung disease.

I'm not fussing about carbon monoxide,

I am. (OK, that was taken out of context - sorry Ivor. Carbon monoxide is something to worry about though)

Make the measurements, if flue cross section is less than 15% of fireplace cross section (1:7 ratio) then you should do something about this. Ventilation into the room from outside should also be 50% of the flue size. Finally fit a CO monitor near to each fireplace - they are cheap so it is just not worth risking your life not fitting them.

A chimney balloon can be a big help in reducing drafts and wasting heat when the fireplace isn't in use.

 

[88v8]

..... the mess of dust open fires create.
I'd forgotten that a fire is a "responsibility".
I found myself sitting in the room with the fire when I wanted to be somewhere else so as to not waste the heat what little there was of it.
...the mess traipsed in and out from carrying the coal/wood and the ashpan puts me off.

All the above

We soon concluded that dusting is an over-rated activity. Just make sure not to be in the room when the sun's shining in :shock:

...there's no point in just lighting a small test fire for a few minutes - that won't give you a true picture. You need to get a really good fire going for several hours. This will thoroughly dry out the chimney and blast out any cold air "plug" that might exist. Once the fire is going really well, you can also get a subjective view of how warm and comfortable it makes the room feel.

Yes, to the warming effect. But... many fireplaces only smoke when first lit, and an effective chimney won't have a cold-air plug. To that extent, a test fire can be useful in telling you something about the chimney.

Make the measurements, if flue cross section is less than 15% of fireplace cross section (1:7 ratio) then you should do something about this.

Another way of reducing the cross-section of the fireplace (if necessary) is a glass 'blower' across the top of the opening. One sees them in NT properties. This can look less obtrusive. Toughened glass. Despite some Googling can't find the proper name for them.

Ivor

 

[DJH]

We soon concluded that dusting is an over-rated activity. Just make sure not to be in the room when the sun's shining in

I've heard that dust doesn't get any thicker after 4 years........ Anyone know how efficient dust is as insulation!!!

In the two original fire places in our house in one, the kitchen, we have a small stove which is kept alight all through the winter and is the beating heart of the house warming the kitchen of course and, because the stairs rise from the kitchen, the landing and bedrooms above. We are delighted with it and as it only cost €235 from two brothers (who live in caravans ) at the local market a bargain. The sitting room we put an inset fire in which warms the room but is no where near as efficient in giving out warmth as the stove...

In the living room I built the fireplace and flue with the express intention of fitting a stove and it's very warm in here a the moment.
Doug

 

[Keith Bowman]

From the pictures you have posted of your house I should have thought it was crying out for a proper full sized open fire, using tree trunks as logs. You have nothing to lose by trying that first - go for it! If the builders have work to do in that room, see if you can get an under-floor duct installed with a closable vent coming up near the fireplace. It would probably be useful even if you eventually go for a stove.
I have always been envious of people who can keep an open fire going with just one huge log resting on a pile of hot embers and ash. At the farm I worked on as a student they used to light the fire in the autumn and let it go out in the spring.

 

[88v8]

An afterthought... I strongly suggest you don't make your final decision on fire/stove until you've had the other seventeen fireplaces dealt with, the register plates & vents put in.

The reason I say this... all the fireplaces are creating updraft, whether lit or not. More so when lit of course. The updraft takes air out of the rooms, and more air needs to be sucked in from outside to replace it. When first the house was built, there would have been plenty of ventilation around the windows and doors and perhaps under the floors if it has suspended floors.
During renovation, it may be that you have stopped up some of these 'draughts' as they have come to be known. So, how do the fireplaces get their air supply? In my experience, if a chimney can't get an air supply from anywhere else, it will get it by pulling air down another chimney which has a weaker draft.

I have experience of this; in our previous house the sitting room fireplace sometimes smoked back into the room when first lit. And, more so on warm days in the winter, there was sometimes a nasty acrid sooty smell in the room when the fire was not lit. It was not nice, it made the eyes sting. The room had underfloor ventilators for the fire, there was no apparent reason why it would smoke. No other fireplace in the house was affected. I never could fix this or find the cause. Until.... we started using the library fireplace for the first time, after which the sitting room fire never smoked nor smelt again, but the library one did !

What was happening.... I only figured out a month before we sold the house... the four other fireplaces in the house - 2 x bedroom, kitchen, bathroom - were all exerting 'pull' on the air in the house. Despite having healthily draughty windows, there was not enough air coming into the house, so the fireplaces got their air down the chimney with the weakest pull, which was ... the sitting room.
Until we opened up the library fireplace, and then, apparently, the library was the weakest so after that the air came down the library chimney when unlit, and the sooty smell with it.

When you put in the register plates it will change the pull in your chimneys. This may well change the draft in the two chimneys where you want fires. So, defer your final decision, then light some more test fires - or Penners' hog-roast - and decide.

Ivor

 

[Penners]

Penners' hog-roast

A hog roast - yes! An excellent idea, so long as I get an invitation!

Seriously though, I think Ivor's advice may be very relevant.

 

[DJH]

Talking of burning big logs on the fire, there's a quaint old custom carried on every year at a country pub not far from where Vicky lives where a bundle of ash twigs, called a faggot, bound with ash ties are burned end on into the fire and a drink is taken each time a tie is burned through... You could try that Sonya although you might have plenty of guests...

Doug

 

[MatthewC]

I really think that a house with 19 (!!) chimneys would have no soul if there were not one or two "real" fires in winter. We have fitted an open fire in our lounge (fed with air from under the suspended floor) and we have a multi-fuel woodburner in the kitchen (and there are three unused chimneys). The woodburner is undoubtedly the more efficient but there is something about sitting in front of an open fire in the evenings, and we have not noticed any significant amount of dust etc (but perhaps I'm used to it...).

 

[Flyfisher]

The woodburner is undoubtedly the more efficient but there is something about sitting in front of an open fire in the evenings,

Yes, that's the dilemma really.