Yes, Firebox size matters

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EJL923

Minister of Fire
Oct 29, 2009
599
Western Mass
Not that i ever discounted firebox size, but i never really realized what the size meant to burn times until i was able to verify it.

I always figured i had a OK sized firebox (about 2.2 cu ft depending on how you want to measure, could be more) , but i was disappointed in my burn times. I also know i have some overdrafting issues as well as an undersized stove for my house. Fireplace size limits, different subject.

All that means during the cold nights i am feeding my stove every 4 hours if i dont want my furnace to rumble, but i am only able to get about 4-5 splits which equates to about 4.5 cords per winter. My stove is setup for an e/w burn, with up to 24" logs. A north south burn is possible with 11" splits. I took a couple 18" splits and cut them in half with my new saw. I am then able to stuff almost 14 half splits in the box. I then got about a 7 hr burn, without touching a thing. Another disclaimer for people without inserts is that inserts by nature have different burn times, usually shorter due to the fact that they are relying on hot air.

Lessons:
I think I am going to keep a supply of half splits on hand for extended burns, overnight and during the day.
People with east west stoves can extend burn times IF they want to.
Take n/s burns into consideration when purchasing a stove.
 
Not sure what's going on there with your stove. My HI300 is a 2.3 cf stove. I load n/s for the long burns. It takes 18" splits and I stuff about 5 splits and other small stuff. 10 hours later I have a large bed of coals in the back of the stove. One thing that has helped me is closing off the damper area with a soft blockoff of Roxul. It has helped heat the stove up quicker and keeps the stove hot longer.

EDIT - I just looked at the specs of your stove. I think you can stuff an 18" split in there going N/S. Why are you cutting to 11" if you go N/S?
 
My point is, i cannot load a large n/s log like you can. My stove was designed for e/w. A stove that has that ability will produce longer burns due to the fact you can stuff it much easier. If I load 6 splits e/w, they will be falling onto my hearth.
 
18" will not fit n/s. you are looking at the exterior dims, which doesnt account for interior thickness and space from the door.
 
EJL923 said:
Another disclaimer for people without inserts is that inserts by nature have different burn times, usually shorter due to the fact that they are relying on hot air.

Do you mean they're relying on the blower to push heat out instead of getting the radiant heat benefit that free-standing stoves get?

I have the C450 and am getting curious about loading up N/S to get a longer burn too. My burn times are already better this year by squeezing in ~4 splits E/W but that's mainly because my wood is dryer than last year. I have wondered if I could fit more wood overall by trying N/S, then just shut the primary down far enough to strike the balance between long burn and clean burn.

A few other things that I think will improve my overall performance are a block off plate and a rock wool blanket around the entire stove. Keeps the stove hotter, blower air into the room is hotter, so I can turn the air down even farther and extend burn time. Those are back burner projects, but I think they'll help when I can get to them.
 
Yes, most inserts rely on the blowers. A few big heaters which extend onto the hearth give decent radiant heat. I grew up with free standing stoves, and when i got an insert it was a wake up call as to the difference between the two.

The block off plate, well sealed and insulated, will make a big difference.

I would say you can insulate the masonry firebox, but do not insulate the stove itself, you are asking for overheating problems.
 
Here's how I run my insert now that I have put a blockoff (soft) full of Roxul.

During the day I run the stove with no blower. We have the stove in a family room with a large kitchen off to the side. The brick hearth and Cast heat up real hot and hold the heat because there is no blower moving the heat away from the stove. This keeps the rooms nice and warm.

During the overnight burn, stuff the stove and shut her down and run the blower to move the heat out towards the stairs that head to the second level.

The block off of Roxul stuffed in the smokeshelf and damper makes a huge difference.
 
I guess you could call what I have a soft block off plate. There isn't a damper, so where the fireplace tapers down around the 6" liner I stuffed that cavity with rock wool / mineral batts. The only thing is the cavity doesn't taper down to the ~6" vicinity until about 6' up, so a lot of hot air stays up there. Sure it's heating the brick surround which then radiates, but I'd rather throw the heat into the house to heat us and the objects.

I meant to measure what size N/S split I can fit, still want to try that.
 
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