Stove BTU sizing question

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AngierNC

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Hearth Supporter
Aug 16, 2010
11
Angier, NC
My old stove was rated at a max output of 40K BTU/hr. The house size is 2,600 sq. ft., with the stove centrally located, but we use it only for warming up the family room on winter evenings (room is about 20x20). On those rare occasions when we lose power in the winter, we can keep the entire house at a reasonable temperature with the stove. The stove responded fairly well to cutting back the air supply so we didn't get driven out of the room where the stove is located.

It's time for a replacement stove and we wanted to stick with a top-loader design and have been looking at the Lopi Leyden and the Quadra-Fire Isle Royale. Those are rated at 73K BTU and 66.7K BTU respectively, quite a bit higher than my old stove. I have no feel at all for how that higher potential heat output will work in my situation. Will I be able to effectively control the heat output on either of those stoves by reducing the air intake so as not to overheat the immediate area? Hearth size and clearances are compatible with my existing stove, so no issues there. Night time winter temperatures here in central NC are somewhat mild and we don't use the stove overnight or during the day time, so burn times and overall efficiency are not prime concerns.
 
I just bought a new stove last spring and have burnt it for about 2 months so still learning but I finally decided if the new stove held as much wood as the old one (guve or take a little) and they are much more efficient then it will do the job the old one did or it is a POS. :lol:
 
The new stove will burn differently than the old stove. Depending on the stove, the burning process will be slightly different. Benefits will be be less wood consumed and the new stove will put out about 90% less smoke. One of the reasons it can do this is that it is burning the wood gases much more thoroughly. It doesn't allow one to completely close off the air to the fire. Doing so can let the fire smolder which produces a lot of pollution.

Burning in the new stove, there is a learning curve, but it's not difficult. In the older stove you might load it up, let it start burning, then throttle it way down. If you went outside and checked the smokestack you would likely see quite a bit of smoke coming out of it. An EPA stove will squeeze more heat out of a load of wood, so with a modern stove you will get a similar result by not filling the stove. Just burn, 3 splits of wood instead of 6. You can still turn it down, once the the fire is going strong, but a certain amount of air is still being metered into the fire for much more complete combustion. If you go out and check the smokestack, there will be no smoke. So, although the stove's output might be 40K btus, many of them can be run at half that output and still burn cleanly.

What make/model stove would the new stove be replacing?
 
I see on another posting that the current stove is a Nu-Tec AM-40. Is this the catalytic model? If so, we are talking a different animal here with a different burn cycle. Cat stoves are better at low burns, even the new ones.
 
Both the Lopi and the QF look like an awful lot of stove to me. Your old stove was rated at 40K BTU, but I can almost guarantee that most of the time during a burn it puts out less than half of that amount of heat. Still, sometime you need to throttle it down, so maybe it's putting out <10K BTU then. The big stoves are going to be hard to run clean with any amount of wood at that output. Sure, you can run it with three small splits (and never less than three), but even then you will have to let it go out and allow the stove and room to cool down or risk blasting yourself out. Not very convenient, nor does it offer much in the way of stable temps. It could work, but is not ideal IMO.

If top loading is not a major factor (although it is very nice feature), I'd look for something just a bit bigger than you have, that will be able to put out a steady output of heat but with more efficiency and cleaner burns. JM2C.
 
Does any one know if the old stove BTU ratings were done in the same way as the new EPA stoves?
 
If this is the cat stove, I think it is EPA rated. And if so, it has me wondering why replace it? I agree with BK that top-loading wouldn't be a high priority. Given the description I would be checking out a Woodstock Fireview which seems like a nice fit for this application.
 
I think the Woodstock is a good idea. But between the two choices you mentioned, I'd pick the Quad over the Lopi. The Lopi is a downdraft stove, and to get a good, long burn you may end up pushing out more BTUs than you want. My sense is the Quad may give you a little more control when you want less heat. But even more control with the Woodstock.
 
Random thoughts . . .

I believe Jotul is coming out with a top loading stove this month (or maybe it's next month) . . . it's new though and I can't remember how many BTUS it's rated at though.

Top loaders . . . for the life of me I can't understand why some folks have such an attraction to top loading . . . well maybe I do . . . it's what some folks got used to using (much like I got used to using an ash drawer for removing ashes) and now I find that to be a desirable feature . . . that said . . . I wouldn't restrict myself to only top loaders . . . there are some very nice side loaders.

Controlling the heat . . . in an EPA stove the easiest way to control the heat output is not with the air control (since shutting down the air with one of these stoves actually helps create the conditions of secondary combustion which in fact results in more heat) . . . rather you can control the heat with the fuel load -- how much wood you load into the firebox, how often you reload, the size of the splits and rounds and the wood species (dense wood vs. less dense wood.)
 
firefighterjake said:
Controlling the heat . . . in an EPA stove the easiest way to control the heat output is not with the air control (since shutting down the air with one of these stoves actually helps create the conditions of secondary combustion which in fact results in more heat) . . . rather you can control the heat with the fuel load -- how much wood you load into the firebox, how often you reload, the size of the splits and rounds and the wood species (dense wood vs. less dense wood.)
This is one thing I find very interesting with the EPA stoves, I did do this some what with my old stove (as far as types of wood and size of load) but I believe I will learn to use this process much more this winter other wise I will not be getting the best use out of the stove.
 
A Woodstock Fireview would be a great stove for you especially considering the location.

Woodstock Fireview


As a hint, we live in Michigan and have heated with the Fireview for 3 full winters (our only source of heat) and love it. We burn only about 1/2 the amount of wood we used to burn and stay much, much warmer.

We did not set the stove on the floor but built up a hearth 16" high. This way we sit on a chair while loading the stove and don't have to bend or get down on the knees when we load it. The cat allows you to keep the fire low and also burns the wood so good that if you have dry wood you won't have much or any creosote. For example, we've cleaned our chimney once in the 3 years we've used the stove. In addition, look at Woodstock's guarantee on their stoves. You will not find another company willing to put out this guarantee.

Good luck.

One more thing. There are some tricks you can use to get that warm air into other areas of the house.
 
Backwoods is there a post with a picture of your 16 inch high hearth as that is something I would love to do with mine.
 
If the old stove was a Nu-Tec AM-40, it is a cat stove. Just guessing by the rating, I would take a swag at ~2 cu. ft. of firebox. If all that is true, the Quad at 3.0 cu. ft is quite a bit bigger stove. The Quad also likes to run at 500 °F or greater. 460 pounds of cast iron at 500F is quite a bit of heat. BUT....at 2600 sq ft. of home, if you can move the heat, it might just be a super star.
 
oldspark said:
Backwoods is there a post with a picture of your 16 inch high hearth as that is something I would love to do with mine.

But if you post such a picture of your hearth make sure you're in it, scowling and wearing the Woodstock sweater vest . . . the one you're raffling off next month. ;) :)
 
These pictures were taken as we were installing the stove.

Woodstove-1.gif


Woodstove-2.gif


Sorry Jake. These are old pictures.
 
Looks good, the height I want to do, thanks for posting picture backwoods.
 
We keep a chair right by the stove and simply sit on the chair when reloading the stove. It works great.

In addition, there is enough room on the hearth to store wood for the next burn. We use that at night. On the opposite side of the stove is a wide place which works great for drying boots, gloves, etc. Sometimes it is also nice just to sit there and get warm.
 
That is a beautiful stove!! Backwoods
 
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