ash dump for air?

rai_in_mdDecember 17, 2004

I have a large fireplace that I've used maybe twice since moving into my house 6 years ago. DW would like to start using it occaisionally, but really for 'fun', not for heat. In fact, we both think that it's probably going to make the house colder to use it.

I've replace the old rusted out ash dump door and I'm getting a chimney cap because the flue tile is crumbling around the top. The flue itself looks quite 'clean', like the fireplace has hardly been used in its 45 year lifetime. There are no doors on the front, just a semi-rusty pull chain screen.

Anyway, I'm wondering if it's feasible to use the ash dump as an outside air source. Am I asking for trouble? Is this likely to cause ashes to start flying around the room? Is there any real danger in hot cinders potentially falling down the hole?

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I'll take a stab at it. See what falls out.

1) Tending any fire takes quite a bit of effort. If you have to regulate that little door much it might mean running outside a bunch of times to mess with it; a pain.

2) I assume the hole comes verticaly up thru the fire so it would sure give it air but might give it too much and burn up the wood faster than desired. Back to # 1.

2a) Is the fire built on the floor or on andirons? If on andirons the hole probly would be moot.

3) Ashes wouldn't fly into the room except sparks from the wood popping which would happen anyway and besides the screen would stop those sparks (supposedly). Gotta keep yer eyes pelt.

4) Probly hot coals could fall down the hole which would ultimately choke off ie loss of control. A guard around the opening of some sort would be prudent depending on the surroundings like if there is dry grass, wood etc.

5) Think! There must be a reason nobody else does it that way.

    Bookmark   December 19, 2004 at 12:48PM
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Thanks for taking the time to reply. I'm just getting back to this...

I forgot about the little door outside. It's actually rusted off its hinges and is just leaning against the opening. The ash dump is just a revolving flap on a frame that lays flat on the fireplace 'floor'. I'd just tap it to open it up. I have a pretty conventional grate inside to build the fire on and the dump opening is centered towards the very back of the fireplace. I guess I'm concerned that an updraft could blow the ashes about, but frankly, most of the draft would still probably come from the room air, since I don't have glass doors (just the mesh screen).

Why doesn't anyone else do this? Well, this is my third home with a fireplace and the first one that even has an ash dump, so I wouldn't know. I figure that this topic/thought doesn't come up much. I did find a company that sells the Air-A-Lator which is a metal box that covers the bottom of the fireplace and is designed specifically to use ash dump supplied air. Also, it wouldn't make much sense to use ash dump air if the dump cleanout is in the basement... that would still be indoor air, so that narrows the field of 'players' even more.

When I build a fire next, I think that I'll just try opening the dump lid and see what happens... By posting, I was hoping to flush out a "Oh it's a great idea, I do it all the time" or "Don't do it, you'll have a mess on your hands!"

Thanks again!

    Bookmark   January 7, 2005 at 10:57AM
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Rai, if you are looking to get combustion air you may not have to look much further than your 43yr old house. If it's as leaky as mine there would be plenty of air for a fireplace draft. I suggest since you and TLW are going to use your fireplace for "fun" (elbow, elbow, snicker!) a good set of glass doors would pay in the long run. They'll replace that antiqued screen, control the massive chimney draft settling the fire down and look very nice as well. You would not have to wear a fur coat on the bearskin rug in front of the fire.

The fresh air inlets that I have seen are just above the fire so there isn't a blast furnace effect rapidly burning up your wood supply. Fresh air inlets are a relatively new addition since homes became more airtight.

Have fun!

    Bookmark   January 8, 2005 at 12:23AM
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I have a 58 yo house and understand what you are trying to do. Your problem is not an airtight house. Your problem is that all of the warm air floating about your house (that was heated by your regular furnace) is being sucked up the chimney by the draft. You may as well be burning stacks of cash. The heated air in your house is now being replaced by cold air leaking in through doors, windows, joints, uninsulated walls, etc. That cold air now must be heated by your furnace. So when you use the fireplace, the furnace runs more than it would if you didn't use the fireplace in the first place. A dilemma for sure. I have the same type of ash dump as you, but mine empties to a little cinder block vault in the crawl space (??) and is pretty much unemptyable. I don't use the ash dump for air inlet. This is for a couple of reasons:

1. The "fresh" air coming from the ash dump would actually be coming from my crawlspace. This would quickly be replace by outside air through the foundation vents. If its freezing outside, this would result in frozen pipes sooner than later.

2. I'm afraid of a burning ember getting into the crawlspace and catching the nice and dry 58 year old floor joists on fire.

3. Nobody else does it.

If your chimney is on the outside of the house, you may be able to modify it to draw fresh air into the firebox from the outside. Drill holes? Probably not a good idea, but would probably work. My advice in the end: you have an old fireplace... deal with it. Enjoy the nice fire & do not expect to save any money on your heating bill.


PS. If the fireplace is not in the same room as the thermostat, try isolating the room the fireplace is in (close doors, hang blankets or quilts in open doorways with no doors, etc.) This may make the temp in the fireplace room a little cooler, but will keep the rest o fhte house at a constant temp. Just an idea...

    Bookmark   January 12, 2005 at 4:05AM
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I replied back to this thread, but the reply is missing(?).

I know the house will be colder from using the fireplace, both while it's burning and actively drawing house air up the chimney; and after it's burned down, but not out and the flue is open all night. That's why I've barely used the fireplace in six years. We think the kids should experience the fireplace, though, so we're willing to "pay for it" ocaissionally.

Glass doors for the large 43"x31" opening seem to be around $1000 and up, and we don't really want to spend that much for the small amount that we'll be using it. I'm just wondering if using the ash dump as a vent might lessen the pain (cold).

Thanks All for responding!

    Bookmark   January 13, 2005 at 12:25PM
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Couple suggestions:

Build "yer far" in the spring and fall when its too warm for the furnace but cool enough that you want the chill off.

Cook hot dogs on rods or some such thing in the flames and make it a semi-yearly tradition for yer kids. Mine dug that kind of stuff, maybe yours would too.

    Bookmark   January 15, 2005 at 9:19AM
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The fair weather comment occurred to me as I lamented that the weather has suddenly turned cold again (here).

I have a brick hearth, so I'm hesitant to do any cooking, marshmallows, etc. in the fireplace... (hard to clean)

    Bookmark   January 15, 2005 at 6:51PM
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One thing we used were those popcorn packages. They look like an aluminum pie plate with a wire handle and an aluminum foil top. Wave it at the fire and the popped corn expands the foil. The kids really liked those - each had their own.
I spose they still make em but that was before microwave. In fact we carried em hiking in the high Sierras....


    Bookmark   January 16, 2005 at 1:02AM
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Let's see if we can't summarize this issue.

The reasons for wanting a cold air intake are sound - these are required in many states for new fireplace construction. Air is needed to feed a fire. Better unheated cold air from outside than heated air from inside.

If the ash dump is drawing air from the basement, this wouldn't solve your problem but would be no worse than your furnace drawing air from the basement - unless they're both burning at the same time. If there is too much internal draw you can create a vacuum and get into CO2 problems.

Best solution is a fire-proof and insulated cold air draw from outside. The ash-dump could possibly be modified.

The Air-a-lator link is provided. They strongly caution against an air intake in the rear for the fireplace. That would blow ash into the room. Similarly, an intake above the fireplace wouldn't serve the purpose of feeding the fire and would blow ash into the room. Any intake should be in the lower front and have an adjustable damper.

Last piece of advice - Home Depot has fireplace glass doors for $120. A worthwhile investment if you're going to burn.

Here is a link that might be useful: Air-a-lator and Chim-a-lator makers

    Bookmark   February 16, 2005 at 5:43PM
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What about using the ash dump for combustion air in the case of a wood-fired fireplace insert? (assuming the ash dump ends up outside) The combustion air would not enter the combustion chamber directly; but rather, through the dampered air intake built into the unit. So no worry of ashes blowing around.

    Bookmark   February 2, 2009 at 2:24PM
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Last year I upgraded my open woodburning fireplace with a woodstove insert. The old fireplace had an ash dump with outside access. The new stove does not have an ash dump. It does hoever draw fresh air from the bottom. When I burn to heat the house I end up drawing cold air throughout the house, to prevent this I have opened my ash dump door to the outside. It works perfect while burning. However when I am not buring a strong cold draft can be felt around the stove. Is there any solution to automate or at least operate a damper from inside my house to control the ash dump opening? Also is there any safety concerns drawing fresh air from the ash dump. It is only open to the oustide.

For More Info Please Visit :

Here is a link that might be useful: EBRIndia

    Bookmark   August 7, 2014 at 3:59AM
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