Airtight, Draft and OAK Questions?

[Mr A]

I took my Jotul C450 out of the garage and into the yard for a test burn. With air control all the way open it would not burn with doors closed, smoke was pouring out of the door edges, and glass edges. I was thinking it would just vent out the flue collar like it should with a 15' liner attached. I am guessing that since there was no liner attached, there was no draft created to keep the fire going? Also, I read a lot of references to airtight stoves. Since smoke was leaking out the closed doors, it is not airtight. This insert was a Craigslist find taken from a foreclosed home. The DOM is 2005, and the chimney cap is fairly clean indicating low use. How air tight should it be? This insert also has a 3" round duct to attach an outside air kit. I would have to knock a hole out the back of my masonry fireplace to run OAK into the garage. There is no gas in there to worry about, but wouldn't it create a hole for cold air to come in the house through the insert? The rope seal around the doors still looks new, no yellowing. The glass is held in place with metal clips screwed to the side. Suggestions, thoughts appreciated.

 

[Wood Heat Stoves]

You're exactly right, since there is no chimney there is no draft. The term "airtight" is relative. No airtight stove is completely airtight. The stove relies on the draft from the chimney to suck air in any openings. A better term would be air controlled. The stove should be tight enough to let you control the rate of burn by controlling the air. Outside air is not necessary unless you're in a mobil home where it's required or if your house is so tight that there isn't enough air infiltration to allow the stove to burn properly which is unusual.

 

[Mr A]

Thanks. Looks like your in my neighborhood, Roseville here.

 

[begreen]

EPA stoves are not airtight, though I occasionally see erroneous marketing literature and websites stating that their stove is "airtight". Newer stoves allow a small amount of air even with the air control closed in an effort to avoid smoldering and smokey stoves.

 

[Wood Duck]

You need a flue to pull air through the stove. With a nice draft from the flue you probably wouldn't see smoke leaking out (although it is also possible that the door gasket leaks). When my draft is messed up due to wierd weather or a cold chimney I sometimes see smoke leaking out of the stove. When the flue warms up I never see nor smell any whiff of smoke. If you have some flue pipe handy I think even 5 feet of pipe would make a dramatic difference in the burn, although 5 feet probably wouldn't create enough draft to let you close the door and maintain a fire.

I do not think an OAK should be vented into a garage. This seems like a dangeerous situation because stuff like gasoline is stored in garages, and gasoline fumes would definitely not be something you'd want pulled into the stove thru the OAK.

 

[nate379]

Not unusual at all with new homes.

your house is so tight that there isn't enough air infiltration to allow the stove to burn properly which is unusual.

 

[corey21]

How much better would a OAK improvve a stoves performance?

 

[Pallet Pete]

How much better would a OAK improvve a stoves performance?

Our previous stove was fantastic with an oak kit however the new one does not need it. I think it really depends on your home how air tight it is as they take outside air in. without the oak if you have a drafty home it will pull air through all of the cracks in the house and cause it to be consistently drafty. In a well insulated home there may not be enough air for the stove to use and that can be dangerous as it will use the air you breath. Performance comes in if your stove is an air hog like our old one the new one does not use nearly as much air so it really isn't needed.

Pete

 

[corey21]

How much better would a OAK improvve a stoves performance?

Our previous stove was fantastic with an oak kit however the new one does not need it. I think it really depends on your home how air tight it is as they take outside air in. without the oak if you have a drafty home it will pull air through all of the cracks in the house and cause it to be consistently drafty. In a well insulated home there may not be enough air for the stove to use and that can be dangerous as it will use the air you breath. Performance comes in if your stove is an air hog like our old one the new one does not use nearly as much air so it really isn't needed.

Pete

Thanks Pete.

 

[Mr A]

Something I read about open fireplaces, that contributes to their inefficiency, is that they pull air from the room you are trying to heat so whatever heated air in the room, it get sucked right back in to keep combustion going. I would think a stove is doing the same but much less.

 

[begreen]

That's correct, fireplaces are very inefficient and polluting. An open fireplace with say an 11" ID chimney is going to draw a tremendous amount of room air out of the room as it cools down, while providing little heat to the house. A stove or insert on the other hand with a 6" liner is going to pull significantly less air as it cools down, while still providing heat to the living space.

https://www.hearth.com/econtent/index.php/articles/upgrading_fireplace
http://www.woodheat.org/fireplace-inserts.html

 

[SteveKG]

Something I read about open fireplaces, that contributes to their inefficiency, is that they pull air from the room you are trying to heat so whatever heated air in the room, it get sucked right back in to keep combustion going. I would think a stove is doing the same but much less.

Fireplaces are a great example. Just stand a few feet before one that is burning some wood, light a match or whatever and blow it out to get some smoke. The smoke will race to the opening of the fireplace. That's why I build an ash dump into the floor of my fireplace that has an air supply for the fire. It makes a huge difference. That makes it an OA-supply, of course. I welded up a door I can close off when the fireplace is cold. I had planned on constructing outside air sources for my wood stoves, too, but that did not get done right away as I built the place. Meanwhile, I moved in and began using stoves. Turns out, they do fine without the outside air, so I've never gone ahead and built them. The fireplace, however, does very well with one, and there are no cold drafts across our feet or backs when using it.

 

[nate379]

Even with an OAK on my stove if there is a low draft (warm, humid, etc) I have to keep an eye on it. If the bath fans are on and the dryer it sometimes starts to smell smokey in the house.
Opening a window an inch or two solves that.

This is even after I CREATED an air leak in the house. In one of the interior stud cavitys I put in 3 2" PVC pipes that vent into the attic. It allows air to be pulled into the house.

First year I moved in it was so air tight that it was hard to close the front door if the dryer or bath fan was running.

I guess between that and decent insulation its why I can heat the house on just a couple cords of wood.

 

[LLigetfa]

In a well insulated home there may not be enough air for the stove to use and that can be dangerous as it will use the air you breath.

That is a common misconception. A stove cannot consume the air you breathe. Only an unvented open flame could do that.

A stove could however lower the neutral pressure plane enough to cause another vented appliance to reverse draft and spew carbon monoxide into the home.

 

[Pallet Pete]

Stoves use air as the fire can't burn without it ! Without outside air it takes it from in the home and with a well sealed home and no leaks its the air your breathing. How is that not using the air you breath? Not trying to be a jerk I am just trying to understand!

Pete

 

[Mr A]

Seems you do understand, as you are correct in your statement. The house is not a submarine, there will be air always coming in from somewhere. If a house is so tight you have to worry about sucking all the air out of it, crack a window open and let in some air! I got my Jotul C450 in. It drafts well and heats well. I was unable to get my block off plate in or my surround installed. My liner wouldn't bend to where it needed to be to get the surround on. I had enough room to shove the insert further into the fireplace opening, but behind the face of it. The outside of my chimney is warm at the height of the smoke shelf, losing a lot of heat without the block off plate. Still, with a fan in front of the insert, the ceiling fan going, and the central air fan going, the house is getting up to 70 degrees F, rising 1 degree about every hour. I didn't get the blockk plate in because I couldn't determine where to cut the hole so that I could still get it into the insert. It was a major pain in the #*!SS to get it in at all!

 

[semipro]

Stoves use air as the fire can't burn without it ! Without outside air it takes it from in the home and with a well sealed home and no leaks its the air your breathing. How is that not using the air you breath? Not trying to be a jerk I am just trying to understand!

Pete

If the house were that tight the stove would go out or smolder but it would not use up the air in the house. The only way at stove would "use it up" is if it were vented back into the house, replacing the oxygen and nitrogen with carbon monoxide/dioxide, water vapor, and some other combustion byproducts.

A house that tight would not support humans very long anyway as respriation has basically the same effect as combustion...using oxygen, producing CO2 and water vapor.

 

[Pallet Pete]

Thanks semipro! I didn't put 2 and 2 together till I thought about it a little more then I went du lol. Your explanation makes more sense.

Pete

 

[madison]

IMHO, if you have a cloths dryer that vents outside the laundry room (even with the "critter" flaps), or a bath exhaust, stove hood etc, you have an outside air source. If there is an airtight connection from the OAK to the stove air intake I possibly would consider the OAK an advantage in a normally constructed home.