can a wood insert be too large for heating space

[Gooserider]

I would like to understand the "fire science" behind a stove being too big and the small fires in it causing increased creosote deposits. The original poster asked something related to this a couple of times.

If I COULD fit 8 splits of wood (just assume splits are a standard size. 5 lbs of wood each, ok?) into my stove, but I just burn 3-4 at a time for most fires, in my stove that's a small fire. But in a smaller stove, it's a big fire. Same amount of wood, same BTUs, secondary burn etc., so why, in my big stove, is it now considered a heavy creosote-forming fire?

Is it because the large stove is designed for a certain amount of airflow for an assumed full load, so my 4 splits really do burn differently in a big stove? But what is it about that design that leads to cooling, as I would think more air would just mean a hotter/faster fire. If that were the case, my 4 splits of wood may not last as long in my stove as they would in a smaller stove, and would be burning cleaner, not dirtier.

Also, wouldn't attempts to get a longer burn out of a smaller stove often lead a person to damp down too much, resulting in a smoldering, dirty burn?

Thanks in advance for clearing up these burning questions!


PS: pssst, scobo: go for the big stove!

Mostly the idea is that it takes a certain minimum temperature to kick off secondary burning, which requires you to get the mass of the stove up to secondary burning temps, and keep it there. A small fire in a big stove is going to have more trouble doing that, and if it doesn't do secondary burn, then it's sending the unburned stuff up the chimney. The airflow issue you mention is also a factor in that it will make your small fire burn slightly faster, but not really enough to make a big difference.

OTOH, it is not supposed to be possible to damp the fire down too much in a small EPA stove, as part of the EPA design is a limit on how much you can restrict the airflow in order to keep the fire burning cleanly - however if the stove is modified, or operated wrong (shutting down before the fire is well established) then you might get some excess smoke.

Gooserider

 

[Bill]

I have a cabin so my situation may be a little different, because we start with an ice cold building. But I had a smaller stove and tried to get good overnight fires and dampering it down to much, also creating more creosote. I now have a stove that is rated for 2 1/2 times the size of my cabin. It works great, but when it's 27 below zero and 30 mile an hour winds, it does not put out enough heat. I have 19 foot ceilings and lots of glass. But my point is you can char the wood and damper it down without producing to much creosote. The negative side to a large stove is in the shoulder season, it's very easy to overheat the house. Had to open the windows a few times. So my next investment is a screen to burn it with the doors open, to keep it cooler in the house.

The store your going to buy it from, ask him if you buy the smaller stove, if it's to small can you return it and pay the difference for the bigger one. Let us know what you buy and how it works out for you, and good luck.