1. Welcome Hearth.com Guests and Visitors - Please enjoy our forums!
    Hearth.com GOLD Sponsors who help bring the site content to you:
    Hearthstone Soapstone and Cast-Iron stoves( Wood, Gas or Pellet Stoves and Inserts)

How to correctly size fireplace for new insert?

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by CA Heat, Nov 28, 2012.

  1. CA Heat

    CA Heat New Member

    Joined:
    Nov 28, 2012
    Messages:
    4
    Looking to upgrade our inefficient open fireplace with a wood burning insert.

    After reading around a bit, I am still unsure on how to properly size the fireplace opening. I have looked at several brand's sites (Quadrafire, Osburn, Lopi), and have found several possible models, but the specs don't seem to line up.

    Below is a pic of my fireplace, with dimensions. My question is this...can the smoke hood be removed so that the front opening can use the full 20 or 21 1/2" dimensions? Or am I limited to only what will fit under the hood lip at 16 3/4", even though there is about 28" behind the hood to the damper?

    Any input on brand recommendation would also be appreciated! I am looking to greatly supplement or replace my primary heat of my 1900 sqft home.

    Thanks !

    FP DIMS.jpg

    Helpful Sponsor Ads!





  2. RSNovi

    RSNovi Feeling the Heat

    Joined:
    May 12, 2010
    Messages:
    298
    Loc:
    Michigan
    Great post. I have the same fireplace and have been wondering the same thing. Being able to go to 22" opens up many more options.
  3. Heatsource

    Heatsource Minister of Fire

    Joined:
    Dec 19, 2011
    Messages:
    762
    Loc:
    Northern CA
    21.5, the smoke deflector can be removed
  4. CA Heat

    CA Heat New Member

    Joined:
    Nov 28, 2012
    Messages:
    4
    This is the tag of the existing fireplace: FP Tag.jpg

    Thanks again for looking and for any input.
  5. JRJ

    JRJ New Member

    Joined:
    Nov 28, 2012
    Messages:
    62
    Loc:
    Southern Iowa
    I'll be watching this one! )
  6. CA Heat

    CA Heat New Member

    Joined:
    Nov 28, 2012
    Messages:
    4
    Dave from A1Stoves...

    I looked at the deflector, and from what I can tell, it when removed, the opening dimension would be 20", since the trim would still drop down the other 1 1/2" and doesn't appear that can be removed. I would assume that getting "creative" with a sawsall would not be allowed per code, though would open that additional 1 1/2" without compromising the integrity of the firebox.

    Smoke trim.jpg
  7. Eaglecraft

    Eaglecraft Member

    Joined:
    Aug 18, 2010
    Messages:
    199
    Loc:
    Eastern Idaho
    Actually, a Dewalt cordless right-angle grinder with a metal cutting disk might be a better tool for cutting out the trim. These grinders cut steel like butter.

    More importantly, it's likely that you will have to cut out your damper in order to get a 6 inch SS flex pipe down to your stove. Dampers frequently interfere with the required pipe diameter because dampers may only be 3, 4, or 5 inches wide. The proper installation is a SS pipe having no joints running from your stove to your chimney cap.

    When you make modifications such as these to fireplaces, I think code requires that you attach a warning to your new stove/fireplace essentially stating that the unit can no longer be used as a fireplace.

    What kind of chimney do you have? What is its condition? Is it masonry with terra-cotta flue? What's the diameter? These are questions that should be answered before you buy the stove, I think.

    We made major modifications to our Superior Heatform fireplace in order to slide a 6 inch SS Flex pipe down the flue.

    Good luck with your install
  8. CA Heat

    CA Heat New Member

    Joined:
    Nov 28, 2012
    Messages:
    4
    Current is a factory built fireplace with 10" steel flue in framed chimney, with standard spark cap. The 6" SS liner should be no issue. Home was built in 1990, CA frame/stucco.

    That trim lip is only sheet metal, and definitely will come right off with an angle grinder, and that would give me the extra height. Most units I have looked at all want 21" or so. I want to get the biggest one I can possibly fit into the space. There are only a few that sit under 20", and their heat output is a lot lower.

    So far looking at:
    Quadrafire Voyageur (46.3k BTU)
    Lopi Declaration Plus (73k BTU)
    I like the Jotuls as well, but all but the smallest one want 22+". The smallest only needs 19 1/2", but only puts out 40k BTU.

    Are the listed max outputs accurate? The Lopi seems to be listed quite higher than the rest. (I know the figures are ideal fuel/condition based, but the Lopi still seems to claim quite a bit more than the others on the market.)

    Not trying to redirect this thread, my main concern is getting whichever I buy to fit! Knowing that some have done some alterations to their old box is good news. We don't plan on selling our home any time soon, and with the stove installed wouldn't be too concerned about anyone wanting to revert to the fireplace anyway.
  9. Eaglecraft

    Eaglecraft Member

    Joined:
    Aug 18, 2010
    Messages:
    199
    Loc:
    Eastern Idaho
    CA Heat:

    I think that you have to take the manufactures' rated output with a grain of salt, because you are actually interested the stoves' effective heat output. There are so many variables with each homeowners insert/stove setup that the stove output numbers should be used as a guide. The "effective" heat output that you obtain will likely be different from the manufactures' because there is not a "standard" stove setup, to my knowledge.

    Consider this hypothetical "standard" install: "The stove room must be 10 feet by 10 feet with 10 feet ceilings. There must be one outside wall in the stove room having insulation of not less than R 16. The ceiling, if there is no living space above, must have R 50 insulation. The finished floor must be red oak. The stove must be placed in a home having low -E glass - and so and so on.

    The fact that each home is different leads to the often made (on-this site) recommendation to "go as large as possible" (up to a point, of course). You can burn smaller fires, place less wood in the box, cut the air intake down, turn the blower down, burn softwoods, open a window. etc. etc... There is some truth to this recommendation, so it's hard to "do it right the first time."

    If it were me, and were designing a new or expensive home, I would take the home design to a heating/vent engineer (there are such academically trained people), and ask for a wood stove recommendation. The engineers can work with the manufacturers' to come with a woodstove or insert recommendation. Otherwise, you can always "pay your money and take your chances."

    Good luck,,,

Share This Page