Fireplace doors - good option


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Old 01-11-09, 10:26 AM
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Fireplace doors - good option

OK - we love our fireplace. We don't intend on using it to heat the house. However, we don't like the idea of it actually sucking up our heated inside air to use a combustion either - or the pollutants that must be going into the house.

I was considering an insert, but they are pricey, and the doors are usually small (not much viewing area).

Now I am thinking about some good tight doors (like the Country Flame 500 series) Country Flame Wood & Gas Fireplaces, & Wood, Corn, & Pellet Stoves & Inserts.
These doors use ceramic glass and are quite air tight.

It seems to me that this would be a good compromise between an open fireplace and an insert. It would be a smaller investment, and we would not need to disturb the existing liner, or add a metal liner with-in our flue. Right?

It seems that these doors would really limit room air needed, and would not be sucking much of our inside room air up the chimney.

Can I have some opinions on this? Do they require very little interior air to keep the fire burning?

We have a brick chimney - stone front fireplace with 4 vents (2 by the floor and 2 just above the fireplace opening on the left and right.
 
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Old 01-11-09, 12:43 PM
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the only draw back to the doors is if you don't have a source of outside combustion air going into the firebox, you will greatly increase the amount of creosote build up in the chimney, also you will have a hard time keeping a visible fire going, mostly you will end up with a smoldering fire that puts out more pollutants. a strong burning fire with dry wood is very clean burning and pollutes very little.

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Old 01-11-09, 02:18 PM
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Fireplace doors - good option?

If putting air tight doors on a fireplace doesn't like the fire burn effectively, how does this compare with a wood burning insert or a wood-burning stove? How do they have a roaring fire and the air tight doors only produce a smoldering fire? Thanks!
 
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Old 01-11-09, 03:03 PM
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they either use room air or have fresh air piped in from outside, the most efficient ones use outside air so as not to pull your heated air from inside the house.

life begins when the kids leave home and the dog dies.
 
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Old 01-11-09, 04:30 PM
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I am really confused now. I know that there are many many people who have wood burning stoves and inserts without piped -in intakes to the outside. So - how is it they have a good fire, using only internal home air with combustion controls??
 
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Old 01-11-09, 05:34 PM
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Please edit your profile to show your location, it really helps in answering this kind of question. For example if you are in CA the '97 California Energy Commission Rules (Subchapter 7, Section 150(e) ) requires "Closable metal or glass doors covering the entire opening of the firebox" AND "A combustion air intake to draw air from the outside of the building directly into the firebox, which is at least 6-square inches in area and is equipped with a readily accessible, operable, and tight-fitting damper or combustion air control device".
 

Last edited by Michael Thomas; 01-11-09 at 06:52 PM.
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Old 01-11-09, 05:39 PM
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Michael,
I am in New York State.
 
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Old 01-11-09, 07:05 PM
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i didn't say you can't have a good fire with internal air, but what happens is when you choke off the air either through a chimney damper or limit the combustion air going to a wood fire you promote the creation of creasote in the chimney. it also makes the exhaust much dirtier. the more combustion air that is allowed into the wood fire the cleaner it burns. all i am saying is using combustion air from inside the house lowers the efficiantcy of the stove/fireplace by causing some or all of the heat produced by the stove to go up the chimney.

how come common sense isn't so common?
 
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Old 01-12-09, 04:54 AM
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OK - so why don't I just bring a pipe in from the outside cellar wall over to the fireplace. With a good set of doors and a cold air supply would I not have a good system without needing an insert or needing to install a flexable chimney liner? I realize that without a blower, this would not produce the heat as an insert, but that is not a priority. Please understand that I am just trying to improve on my basic existing fireplace.

Does the air duct need to be piped directly into the firebox, or can I have it in a wall near the fireplace door intake vent ?

PS - How is outside air brought into an inset where the fireplace is in the center of the house like mine?
 

Last edited by tomfmal; 01-12-09 at 06:41 AM.
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Old 01-13-09, 12:50 AM
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Fireplaces were the latest technology --- in about the 12th century. While putting glass doors on a conventional fireplace does modestly increase the efficiency by limiting the amou8nt of heated room air drawn up the chimney, that does little to extract more heat from the combustion gasses.

So even with glass doors fireplaces are still pathetic as heaters.

Wood stoves and insert improve on fireplaces in two ways--

1) by reducing the amount of heated room air being drawn into the stove and going up the chimney

2) by holding in the hot combustion gasses until substantial amounts of the heat can be added to the room air of the dwelling space.


Wood stoves don't typically have a "roaring" fire when the door is closed and the stove is operating properly. Stoves limit the speed of combustion and hold in those hot gasses until they give up much of their heat.

If you want a roaring fire, you can't beat a fireplace! Fireplaces can easily consume several times the wood of a stove and never overheat a house --- because most of the heat is going straight up the chimney, and heated room air is going up the chimney too. Every cubic foor of room air drawn up the chimney is replaced by a cubic foot of air from outdoors.

You may heat up the room where the fireplace is located, but usually more remote rooms get cold because of all the outdoor air being drawn in.
 
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Old 01-13-09, 05:46 AM
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I have a friend who just had an wood insert installed. I called him about it. I cost him 4K to buy and have installed, and there is no ductwork bringing in outside air (wonder how many of these installations are common). So he is also using room air to feed his fire.

So, Seattlepioneer's difference #1 does not always apply.

I don't see much difference in heat loss between this installation and a fireplace with good airtight ceramic glass doors.
I do understand that an insert will heat the house better because it has a blower, but as I said, my priority is not to heat the house.
I just want to enjoy the fire with as large a viewing area as possible, and limit the room air lost as combustion.
Again, I also have 4 vents built into my fireplace - 2 near the floor and 2 above the fireplace. The 2 top vents produce quite a bit of heat when I close my existing cheap not-so-airtight glass doors.

Can someone please give me some further opinions about this? Thanks!
 
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Old 01-29-09, 05:10 PM
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tomfmal, I am struggling with the same thing. Two low intakes, two high exhausts (they are acutally fan assist which makes a huge difference), steel jacketed firebox, and a crappy, leaky tempered glass door.

I too came on the CF 500 which, so far, seems to be the only "poor mans insert" that I have found - trully adjustable combustion air, secondary air from the top, pyro-ceram doors, airtight gasketry and frame forms to mold the door into the opening. It will work just like an insert, the type with no outside air : combust more of the wood and throw off more of the heat.

Go for it.
 
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Old 02-02-09, 04:41 AM
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I think the other key is to have a good adjustable damper inside your fireplace - I have one that is adjustable but is old and bits are breaking off. I wonder what it takes to replace it - do you need to custom make one?
 
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Old 02-02-09, 05:46 AM
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You mean the flue damper? That "blocks" air from going up the chimney? Mine is off its keaster. I contacted Heatilator and they said the only real way to deal with it was to have a fireplace contractor over to look at it. To be honest, I think if you understood something about it by looking at it and could arc well it would be safe enough to do yourself.
 
 

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