Q&A Firebox size

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QandA

New Member
Staff member
Nov 27, 2012
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Question:

Questions for you thinkers out there: As I read the ratings (woodburners feedback) portion of this website it seems as tho shortness of burn recurs as the most common complaint with most (maybe all) models. Why can't the industry design/manufacture a model that holds a large enough charge to deliver, oh, say, 40,000 BTU/Hr over a seven to eight hour period? Just how large of a firebox would that have to be, given the use of well-seasoned wood of a high quality species.....hickory or white oak? Does this size of a magazine pose too great a threat of a fire hazard?



Answer:

Well, wood contains about 7500 BTU per pound and an efficient stove might get about 5,000 of them out into the house. That means you have to burn 8 lbs per hour to maintain 40,00 BTU. A eight hour burn at that rate would consume about 65 pounds of wood...to say nothing of the bed of embers that you need to have in there before you load the 65 pounds in and the embers you need left even after the 8 hours to rekindle.

So, a stove which held a 75 pound load would do the job. However, there are some concerns:

1. It might hold a 75 lb load of oak, but only a 40 pound of pine since that is less dense.
2. 40,000 BTU output would roast most people right out of the room they were sitting in. Only the largest of rooms which are also open to other rooms could use this type of stove.
3. Suppose you loaded this stove with 65 pounds 3 times every day. You'd burn 200 pounds per day, or about a cord every month (depends on wood species). 5 or more cords of wood a year is a lot to haul through your living area.

If real whole house heating is really your thing, look at the central heaters from companies like HS TARM, Yukon, Energy King and others.

Also, there are fireplace furnaces like the one from Country Flame, which distribute the heat from your fireplace throughout the entire house.

Lastly, there are some woodstoves on the market that are this large...check around...the fireboxes are usually measured in cubic feet - you'd want something with over 4 cubic feet.
 
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