How long does your fireplace burn?

[MossRoad]

Moss, we have a regular (very large) fireplace surrounded by firebrick and what we have is not a damper, but a large rectangular door opening into the chimney. My use of "damper" was a misnomer. My mechanism for the door is stiff enough that I can close the door down somewhat like a damper but with nowhere near the accuracy of a true damper. I'd say I leave my door open 1/3 most of the time and that's enough to have plenty of draft and not leak any smoke out into the room. Our chimney is made of tiles surrounded by filler brick and then outside brick and mortar. The fireplace is a little unusual in that the brick starts on the walkout basement level and the actual fireplace opening is on the floor above. If I had been smart, I'd have asked the contractor to include a metal chimney up from the basement level and have dual stacks within one brick enclosure.

Construction pictures are shown attached.

Beautiful home you have there.

 

[MossRoad]

What I remember about dampers in chimneys is my dad starting a fire on a cold winter morning and promptly filling the house with smoke because the damper was closed. I guess in a fireplace you would not use the damper to control the fire, would you? You would just use it to close the chimney after the fire was out to prevent heat loss in the house, correct?

 

[JB4310]

I read somewhere that one of the oak species has the highest BTU potential, not sure which one though.

As far as using damper to try and control the draft and heat goes, some people do it but most just leave it wide open.
Some may not realize but with a fireplace, that flue can be a 2 way street not only venting gasses up but drawing combustion air downwards, especially in a well insulated "tight" house with little source of make up air.

The taller the chimney the better the draft usually, but there are all kinds of factors that can cause a fireplace to not function well. Make up air is a biggie but also any other oxygen gobbler in the house, like gas or worse, oil fired furnaces, even clothes dryers venting outside.
Depending on which one is more starved for air, can make it difficult to diagnose/figure out why there is smoke, odor or worst co2 in the house. That's sometimes referred to as "stacking" where one appliance will pull it's combustion air through another's exhaust.

Here's a pic of my F/P in the basement cave, this one sits at floor level, I'd rather have the raised hearth of Jim's. I have a steel box to keep the logs in with a grate underneath, that raises the fire off the bottom about 4 inches. My house was built in 1936, there's another FP right above this one in the living room but we don't use it much except for the occasional fake log.

 

[ultrarunner]

I have a Austrian kachelofen ceramic wood stove at the cabin...

One armful of hardwood lasts 24 hours...

If it is freezing outside it's one armful of hardwood every 12 hours.

For those interested... here's what Mark Twain had to say about Kachelofens:

The German stove (Kachelofen)] is by long odds the best stove and the most convenient and economical that has yet been invented. One firing is enough for the day; the cost is next to nothing; the heat produced is the same all day, instead of too hot and too cold by turns; one may absorb himself in his business in peace; he does not need to feel any anxieties of solicitudes about the fire; his whole day is a realized dream of bodily comfort.
The American wood stove, of whatsoever breed, it is a terror. There can be no tranquility of mind where it is. It requires more attention than a baby. It has to be fed every little while, it has to be watched all the time; and for all reward you are roasted half your time and frozen the other half. It warms no part of the room but its own part; it breeds headaches and suffocation, and makes one痴 skin feel dry and feverish; and, when your wood bill comes in, you think you have been supporting a volcano.

- Mark Twain, 1891
excerpted from 鉄ome National Stupidities, from Europe and Elsewhere, Harper & Brothers,1923.

 

[jinman]

Beautiful home you have there.

Thanks Moss. We love the house, but there are lots of things I'd change if I were doing it again. As time and money allows, I may do some of those in the future. Three floor levels with only one HVAC system is a challenge. Today, we have our main living area at 69-70 degrees, but my basement is only 59. I wish I had a wood stove there to boost the temperature a bit in winter. In the summer, it's the best spot in the house.

JB, I like your "cave" fireplace. It's easy to see that it's had a lot of use. I don't think I have any venting problems with my fireplace. In the morning I set my thermostat up from the night temperature of 62 to 70 and then start the F/P. With the damper door all the way open, I've never had any smoke or downdraft of cold air. It draws nicely.

While I welcome all comments (I'm learning alot.), my original comments were to see how the average stack of wood burns in a normal fireplace. I think what I'm finding is there is a large variation based on wood type, dryness, size of pieces, and style of fireplace. I'm very happy with my own fireplace experience so far, but there could be lots of improvements. A wellmade woodburning stove could surely save a bunch on my winter electric bills.

 

[radioman]

try an armfull of hickory!

 

[beenthere]

What I remember about dampers in chimneys is my dad starting a fire on a cold winter morning and promptly filling the house with smoke because the damper was closed. I guess in a fireplace you would not use the damper to control the fire, would you? You would just use it to close the chimney after the fire was out to prevent heat loss in the house, correct?

MossRoad
Not correct the way I use the damper in my house fireplaces. I open the damper to get the fire going and a good draft to warm up the chimney. Then as the chimney and brick get warm, close the damper to just enough to let the smoke up, and not a rush of room air going up the chimney. In fact I close the damper all the way, and immediately crank it open just a smidgen. Maybe a 1/4". Plenty of heat to carry the gases and smoke out.
Each chimney is a bit different and some experimenting needs to be done. Type of wood, type of chimney, the way the fireplace is built, sources of make-up air in the house, dryer and bathroom and oven exhaust vents are all factors to figure into the right procedure.

 

[JB4310]

I wish I had a wood stove there to boost the temperature a bit in winter. In the summer, it's the best spot in the house.

You may be able to still do it, it would of been simple with clay liners during construction, but even now that chimney is hollow from top to bottom, with a little effort you could drop a stainless steel pipe in. The only trouble and this is a biggie, is getting past the fire box, it's not gonna just drop in there and would probably require some modding, should still be able to be done from outside with out disruption to your fire place, you'd only need about 6-7 inches to get that pipe through. then just a thimble breech in the basement and another through the top crown.

JB.

 

[dex3361]

You may be able to still do it, it would of been simple with clay liners during construction, but even now that chimney is hollow from top to bottom, with a little effort you could drop a stainless steel pipe in. The only trouble and this is a biggie, is getting past the fire box, it's not gonna just drop in there and would probably require some modding, should still be able to be done from outside with out disruption to your fire place, you'd only need about 6-7 inches to get that pipe through. then just a thimble breech in the basement and another through the top crown.

JB.

This is what I did to my Wood stove, I have a clay tile liner and I dropped in a 8 inch Stainless steel liner it was in 3 foot sections and I put it together with SS screws. The thing that noticed the most was that my chimney stays very clean it typically drops all of the creosote back down as hard flakes. I made a thimble for the top of steel plate and pipe and put a shroud of ss around it. I brought it down and tied it directly into the Harmon Stove it is a coal/wood stove that work well with or without the blower. I went this route because of power outages like the one we just went through that lasted for 6 days. With the shaker grate you never have to shut down the stove you can clean out the ashes in the bottom with a fire roaring. It will burn 10 hours if I choke it down a bit. I really like the Harmon stove it has a nice rustic look and it is easy to start a fire in.

 

[MarkV]

Jim I think you are getting a good burn time for an open fireplace. My guess is that much of it has to do with using Post Oak, sometimes called Iron Oak, and Blackjack Oak. These are both very slow growing species that are very dense. When well cured they will burn a long time with good BTU out put. It also sounds as if some of your wood may be a bit under cured which will make it burn slow. Not a big problem if you are getting the results you like. You may lose some BTU output and you will want to watch for creosote build up in your chimney.

MarkV