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two stoves, one chimney?

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by Michael6268, Mar 20, 2011.

  1. Michael6268

    Michael6268 Feeling the Heat

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    Grafton NH/Upper Valley
    Ok I know this has been asked before but I have no luck with the "search feature" on this site and couldnt find it. We are in the process of buying a house in NH and they have two chimney flues. Two wood stoves in one- upstairs and basement. And the oil furnace in the other. I know it is a big no-no to mix fuel/exhaust types. But is it ok to vent two wood stoves into one flue? I would imagine at minimal it would require more cleaning, but does anyone know if this set up is legal/ok. The inspector said it is and id done all the time. Havent checked with the town yet.

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  2. begreen

    begreen Mooderator Staff Member

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    It is not legal and should be noted in the home inspection report. Only one solid fuel appliance is permitted per flue. The inspector is wrong. "Done all the time" does not make it right. Hopefully the rest of his report is more circumspect. If not, get a new inspector and beware of good ole boys blowing smoke.
  3. nate379

    nate379 Guest

    I don't know about 2 stoves in 1 flue, but an oil furnace and wood stove on one flue is very common where I grew up in Maine. I'm not sure if it's still allowed now, but it was a few years ago for sure.

  4. begreen

    begreen Mooderator Staff Member

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    Maine has an exception for that configuration. I'm not sure, but I think it still does and is the only state with that exception.
  5. summit

    summit Minister of Fire

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    thank god Maine did. There is a caveat: 1. the chimney must be in operating condition (obviously) and must provide enough sq inches to supply sufficient draft for each appliance. 2. (the grey area) your ins co may or may not approve of it, based on their policies. So, while the state may approve, don't assume your insurance does, too.
  6. Wood Heat Stoves

    Wood Heat Stoves Minister of Fire

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    I'm surprised Maine has an exception for that, because it's against code almost everywhere else. One problem I can think of would be that if you have a large enough flue in cubic inches to accommodate both stoves, it's going to be too large to provide a good draft for either stove operating on it's own, as well as contributing to more creosote build up because you can't get the chimney hot enough.
  7. Don2222

    Don2222 Minister of Fire

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    Hello

    Well, I know for sure that years ago in Salem NH you could have 2 appliances into 1 flue and here is why. Newer more efficient Appliances that actually pressurize the flue with more powerful blowers must have their own flue!! Otherwise operating pressure from one appliance can cause back pressure on the other appliance and blow smoke into the room and set the room on fire or spread toxic fumes into the house making people sick or causing death. So today most towns and states require each appliance to have their own flue. I finally put in a second flue so I now have separate flues for each appliance and believe me they work better and are much safer!!

    Even in your case of two wood stoves on one flue. If the upstairs stove is going good, then you will not get a proper draft thru the basement stove to run well. Not code now in most states!
  8. Exmasonite

    Exmasonite Feeling the Heat

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    Not sure about code but 2 possible alternatives consider:

    - Use chimney for basement stove and put in direct chimney for upstairs stove

    - Use chimney for one of the stoves and replace other stove with a pellet stove that can be vented through horizontal wall. I am in similar situation: 2 flue chimney, fuel oil burner in one flue and wood burning stove on 1st floor goes into second flue. I have a Europa pellet stove in the basement that vents horizontally after a 4 ft rise. Now, the europa is pretty forgiving as far as draft goes. Some other pellet stoves might require a 10-15' rise and an OAK but still something to consider as an alternative to using the chimney.
  9. firefighterjake

    firefighterjake Minister of Fire

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    Maine Legislators passed the exemption a few years back when heating oil prices were close to and then exceeding $4 per gallon . . . the exemption was pushed through since many older homes have the single flue and many folks were looking at purchasing a woodstove or pelletstove at the time and this was created to help ease the costs of heating the homes . . . for better or for worse.
  10. WidowMaker

    WidowMaker Member

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    I can remember living in a couple houses as kids that had both a wood stove and a wood cook stove on one chimney with no problems ...but that was before the government but into micro management of our lives
  11. begreen

    begreen Mooderator Staff Member

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    Ask the "inspector" about NFPA 211 section 9.8.2

    Attached Files:

  12. TX-L

    TX-L Burning Hunk

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    For decades, my grandparents ran an oil burner furnace in the basement and a woodstove on the main floor of their old farmhouse, both were vented into the same interior masonry chimney, both ran just fine, either singularly or simultaneously. Most of the heating season, they would shut off the furnace and cover the barometric damper on the oil burner flue with aluminum foil, so the woodstove was getting the full potential of the chimney draft. That house is still set up that way with no chimney or draft issues.
  13. baurand

    baurand New Member

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    Central PA
    I have a slightly different issue. My house has a single, masonry chimney. I currently have an oil-fired boiler in the basement. I'd like to add a secondary wood-fired boiler to run in tandum with the oil boiler. But with only one flue, I feel trapped. Is there any way to buy (or make) a "Y" type adapter with closable dampers to isolate each of the furnaces? I'd like to make a complete switch to wood only. But with traveling, I'd like to keep the oil as a back-up. I have no intentions of operating both units at the same time. Does this change anything (code-wise)? Or do I NEED to build a second chimney to vent the wood boiler?
  14. cmonSTART

    cmonSTART Minister of Fire

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    Two solid fuel appliances cannot share a flue. That's what NH code says. Whether or not the local authority having jurisdiction wants to enforce it is another matter. Still, I wouldn't recommended for a bunch of reasons relating to both performance and safety.

    What town in NH if I may ask?
  15. cmonSTART

    cmonSTART Minister of Fire

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    BeGreen, FYI NH building code is based on IRC2009, but in this respect it's the same thing as NFPA.

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