Our new home will have a center chimney fireplace. I would like to use outside air for combustion rather than drawing the heated inside air to feed the fire. Is this possible? How can it be done safely? Would a mason contractor know how to construct this?
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I'll respond until others get started. Yes, outside combustion air is preferable for a couple reasons--why "burn" conditioned air from inside your house only to create a low pressure situation that will either casue cold outside air to leak through any cracks there may be, or to cause your furnace or water heater to backdraft? I would think a mason would have several ways of building a fireplace with a duct for providing combustion air; I've also seen double walled metal flues that draw combustion air down through as the exhaust gasses are going up, thus preheating the combustion air. But, I've heard that there can be problems with these, if I remember right, can cause creosote to condense in the flue or draw the flue gasses back in or something.
A separate duct for combustion air would be safest and, in fact, I can see no way it couldn't be safe--just put hardware cloth or something across the outside to keep critters out. Only thing I don't like about ours is that it acts like a speaking tube, so we can here the neighbors talking and playing in their driveway as if they are right in our living room!
Thanks to all that took the time to give me great information. I never thought of the dryer make up air. This will help us as we move forward.
I was on a job site recently and the new fireplaces under construction had outside air intakes built into them. It consisted of a steel tube ( all I saw was the inside the fireplace part ) with a threaded cap on the end protruding thru the firebrick on the side of the firebox about 12"-15" off the bottom of the fireplace. The cap was attached to the tube by a chain. My guess is that one would unscrew the cap when burning and replace it after the fire.
I didn't have time to look it over very well, but I'll be back out there in a week or so and I'll get more info and take some pictures. I'm in the process of designing an addition, so I'm interested as well. It had a brand name on it, but I don't remember it and my googling has fruitless.
http://grantlogan.net/
Any compotent mason should be able to do it.
Here I used 4" stainless steel pipe, ran it into the basement and then to the outside.
Rod
Nice looking job. Two questions: How do you keep the ashes out of it? And, you been starting fires with WD-40?http://grantlogan.net/
"Because I really want to live in a country where the poor people are fat. "- Unidentified Indian Immigrant when asked why he wants to come to America
Hey,
that is one nice Rummer! Does it use a flue and throat kit from superior Clay? I have a five foot wide Rummer with 2 three inch freshair inlets which I put on the sides one fire brick up. each has a shutter. I have since found that proper combustion makeup would be closer to the area of the flue. Mine is 20x20. The fireplace works great, BUT, I haven't finished sealing up the building envelope, so I would say the jury is still out.
That's a beauty!
What sort of fire brick is that? I like how you matched the facing.
Some answers........I can't remember what that can of WD-40 was for for, but no........it wasn't for starting a fire. But.....for some of you more adventurous people, I'm sure it would work! And the spots on the hearth were from our boots walking around the wet jobsite.The grates I use are cast iron, and they have a sliding grate that opens and closes the air flow. It's not ideal, but quite frankly...I have'nt seen anything better on the market.With a Rumford fireplace, the fire should be placed as far back against the wall as can be, especially because they are shallow as it is. This will keep ash from going down the air vent.Still, it is something that you have to be cognizant about. What helps also is the air flow coming from the vent.The bricks are made from soapstone, ($10.00 per brick!) and the facing is granite that was picked out by the homeowners long before the decision to use soapstone brick. Originally we were going to use Morin Red Restoration brick in the fireplace, but after some research the homeowners decided on the soapstone.This was my second soapstone Rumford, the first is directly under the one in the picture, in the basement.On another note, to be honest.........I don't like the idea of fresh air supply. I especially don't like the idea of having the state tell me that it has to be there, but here in CT it is code........so, I only put it in because I have to. I know, I know..........fresh air supply to the fire reduces burning of preheated air, is more energy efficient........yada yada yada. I do mostly 18th Century repro fireplaces and because it's code I have to put them in.........and they look like ####.New houses, no big deal. But, I also don't believe they work. I finally rebuilt the fireplace in the house I've lived in for 12 years and as an experiment I installed a fresh air supply. All it did was turn the fireplace into a blast furnace........sucked up wood like there was no tomorrow.I think what some people have to realize is.........that a fireplace is just that........a fireplace. You cannot turn it into a heat producing furnace no matter what you do. And even though a Rumford is the most efficient way to build a fireplace.........in the end there's still heat loss. Typically you'd start a fire say........mid day on the weekends, or early evening during the week. Go to bed, you still have to leave the damper open because the fire hasn't burned out yet. Get up in the morning.......fire's out and your furnace heated air is going out the chimney. I know glass doors are an option, but if you're going to do that you might as well by a woodstove.A fireplace is................... a fireplace. Rod
Thanks for the reply. You make a mean fireplace! You didn't mention whether or not you used a kit or laid your own throat. Just curious as I have made a couple Rumfords myself and am interested in the throat tiles.
Oh yea ten buck's a brick ouch!!
I've done it both ways although I usually just build my own throats. The 2 times I've used the kit it's because the homeowner bought it and needed someone to put it together. I think he thought that it was a fool proof way to make sure that the draw of the fireplace worked. And it is. But it's tough to part with that kinda money when I can just build it myself. Plus.........you're committed to use their damper which is pricey too. I use "tip & slide" dampers.That being said...........it does save a lot of time........on a new fireplace. They aren't any good for retrofitting an older fireplace. Did that once, again, because the homeowner bought it and wanted to "make it work". It was more like, "make it fit", and would have been easier if I had just done it myself with brick & mortar, but the homeowner insisted. It works, but probably took twice as long to retrofit. But .......he's happy. Rod
You know your right . the reasons I was interested are exactly those-Time saving and some insurance that it will work right. The first isn't that great and the second doesn't make any sense at all! Thanks for saving me some waisted time and money.
A GOOD mason would be able to do this properly. Build a Rumford fireplace - anything less is very inefficient. And, if possible, unless you want to open and close the air intake every time you light or burn out a fire, make sure the air intake pipe has a reverse trap - if it rises 3' and then returns to level it will prevent cold air thermosiphoning into the fireplace when it's not being used.
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Solar & Super-Insulated Healthy Homes
Edited 1/31/2008 12:47 am ET by Riversong
Good trick.
They can't get your Goat if you don't tell them where it is hidden.
Oooh, I like that. Reckon that would be usefull for clothes dryer make-up air?http://grantlogan.net/
"Because I really want to live in a country where the poor people are fat. "- Unidentified Indian Immigrant when asked why he wants to come to America
Reckon that would be usefull for clothes dryer make-up air?
You bet! I placed my dryer make-up air inlet low on the outside wall and brought the duct up 3' before turning it into the inside louver. That way it requires no closing mechanism other than the plastic louvers which open whenever there is negative pressure in the mudroom/utility room. This eliminates the need for "occupant intervention".
All my intake and exhaust ducting has a 3' drop before exiting the building, including kitchen hood and bath fans.
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Bath (left) and kitchen (right) exhaust caps low on wall.
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Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 1/31/2008 12:04 pm ET by Riversong
The outside termination for the dryer makeup air. Is that just mechanically fixed open.Because it need air flowing out to open it.And is the same type of termination used on the inside, but with the air flow in opening the flappers..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
The outside termination for the dryer makeup air. Is that just mechanically fixed open.
No, it's a non-moving screened intake with fixed louvers slanting downward to keep out rain.
And is the same type of termination used on the inside
The inside termination is a hinged louver cap that opens to the inside, and both terminations and ductwork are 6" diameter.Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
I used 1" cast iron pipe connected from the exterior wall to underneath the hearth. It draws well but needs a grate and constant vacuuming.
Expert since 10 am.
Thanks for the information.