Nothing Like the Smell of Fresh Smoke Blowing Back into Your House in the Morning

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boatboy63

Member
Feb 6, 2010
205
Northeastern TN
Got up around 8:30 this morning, started a fire about 15 minutes later. About 15 minutes after that, door temps were around 450* and smoke started POURING back into the house from the stove. We got about 5" of snow overnight and temp was 28*. When the smoke started, temps had dropped to 22* in less than 30 minutes, wind gusts already of 25 mph and it looked like a blizzard as winds were picking snow up off the ground and making it a white-out. When the smoke started, stove temps dropped back to about 375* in less than a minute. Wife turned exhaust fan on over oven to try to get rid of smoke that was enough to choke you. Kept trying to get temp up on stove so it would help alleviate the downdraft effect. It took nearly an hour to get the temps up to 600* and we got to eat more smoke until then. Seems like the wind has died down some now and smoking has quit. Our wind normally comes from the west but this morning, it was coming from the north which just happens to be the same side of the house the chimney is on.

Any suggestions on what to do in these rare occasions when this happens? I tried shutting down damper by about 25% while temp was building up to try and reduce smoke downdraft. Thought maybe if I could get fire hot quick, could close damper on down and reduce smoke. It was so bad, smoke was pouring thru fresh air slides on bottom of doors and you could barely see the stove.
 
Open window in or by stove room and open up door of stove, induce the draft.
 
Turning on the exhaust fan probably made the situation a little bit worse. As the other poster suggested, opening a window will provide fresh air to breathe & make sure you don't have a negative pressure inside.
If you think this is likely to happen again, I would suggest setting up a draft inducer. There are several commercially available as well as many homemade variations which have been discussed here. There are the types which place a fan at the chimney cap, and ones which are placed part way up the flue or chimney which blow up with a venturi effect.
Take a look at how the airflow is around the house & chimney - you may need to add some height to the chimney to get away from effects of the building. Adding height will also generally increase the draft overall.

Don
 
If it only happens with a cold chimney try to start a smaller fire next time.
When you are sure you have more flame than smoke and a better draft and the chimney has warmed up some throw some more wood in.
 
Just to update...after posting, winds have calmed down and we haven't gotten smoke anymore. The lower level of this old house was built in the late 1890's. We have tried to insulate, but when the wind blows, there are more leaks than a screen door on a submarine. Been working on that, but it isn't easy. The main problem is trying to insulate the floor, as there is a limited amount of crawlspace and joists range from 10" - 26" apart. I understand what you are talking about with negative pressures, but with the direction and how strong the wind was blowing, I don't know if anything could have been done. When all this took place, fire was burning well and there wasn't really any smoke in stove. When the wind blew back down chimney, it's like it rapidly smothered and cooled the firebox. We typically never have problems with drafting, even from a stove that has been out for 12+ hours.
 
Sealing upstairs leaks may help here unless it is more a problem of flue location. The wind may be sucking out air from the above floors causing negative pressure in the lower floor. This in turn is sucking air from the nearest open vent - the stove flue. Open a nearby window a little next time to reduce the negative pressure.

Here's a nice article on the topic:
http://www.woodheat.org/chimneys/wind.htm
 
Wind load on structure roofs generally are negative(uplift) at lower roof angles. Somewhere between roof slope 5:12 to 7:12 the windward roof sees down pressure and the lee side sees uplift. Lot of variables in this, but perhaps if you have a steep roof, the chimney top is within the positive pressure zone. This coupled with a high negative pressure on the lee roof and walls will give you pressure differential down the stack.

I agree with the comments about not turning on exhaust fans and opening windows on the windward side of the house to get a draft going.
 
The article linked by BeGreen says it much better than I did. Should have read that before posting.
 
The end of the article describes the 3-2-10 rule...OP's old house may or may not comply.
 
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