Blaze King Model 30 vs. 20 Selection

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Isaiah53

Member
Jun 6, 2014
90
Northern CO
I have a recently constructed two story 2700 sq ft home in the mountains of northern Colorado with a reverse floor plan. There is 1650 ft2 living area upstairs that is well heated by an FPX 44 Elite, and a 1050 ft2 downstairs that currently relies on the propane heated radiant floor system. I am planning to install a wood stove in the 500 ft2 downstairs recreation room to provide more economical heating and to provide some heat to the house during a power outage. Wood is mostly lodge pole pine, Douglas Fir and Englemann Spruce.

The local temperatures routinely run from about -10 F at night to the mid 20's during the day and there are substantial winds, but the house is very well sealed and insulated (R-50 ceiling,R-19 below slab and R-23 plus 1" foam board on walls). I used about 100 gallons of propane per month during last winter, although some is used for water heating and cooking. The downstairs will not likely require a lot of heat. A 5100 Btu/hr electric space heater in the rec room raised the temperature in the rec room from 56-58 F to about 65 F with the upstairs running in the mid 70's.

I originally planned on installing a BK Ashford 30 because of its controllable low heat output. I also like the concept and appearance of the cast iron wrap of a steel box like the BK Ashford, PE Alderlea and Enviro Boston lines. I thought about waiting for the Ashford 20 to come out, but in looking at the stove specs, there appears to be little if any advantage in the smaller 20 models in terms of low heat production. Both are rated at about 12,400 Btu/hr, although the heated area rating of the 20 is about 20% lower. It appears you mostly give up wood capacity and burn time with the smaller stove. Now my installer is saying the 30 is probably too much heat output and suggesting I wait on the Ashford 20. He has even suggested one of the very small 1 ft3 firebox type heaters like the Jotul F3CB

I have read comments on this site to the effect that there is no benefit to the 20 other than its smaller footprint, as the specs would suggest. On the other hand it would seem the smaller box would have to offer less surface area for heat transfer and should have a lower heat output for the same stove temperatures. I am interested in hearing experience or opinions with regard to which size stove I should select.

Attached is a floor plan of the lower level. The lower floor is a walk-out basement type design although all of it was originally fully insulated as living area. The interior wall between the rec room and the hallway shown in the drawing was not installed so the stairwell and the bedroom doors open directly into the rec room. The stairwell is open to the upstairs living area and there is a ceiling fan in the center of the rec room to spread the heat.

I really appreciate this site for the information it has provided and look forward to your responses.
 

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I don't know, maybe with the 30 you could heat the entire house with one stove when temps aren't real low. Only having to feed one stove would be an advantage.
Yeah, hard to believe those low-heat figures. My 2460 is rated at 6600 btu low. Could be another case of the EPA numbers not relating to real-world use.
 
BK's btu numbers are pretty honest.

At a low setting, you have a bunch of wood smoldering, not making much heat at all. Then you have the cat consuming the smoke from the smoldering wood. The same cat in the 20 as in the 30..... Not sure you would feel a real world difference.
 
BK's btu numbers are pretty honest.

At a low setting, you have a bunch of wood smoldering, not making much heat at all. Then you have the cat consuming the smoke from the smoldering wood. The same cat in the 20 as in the 30..... Not sure you would feel a real world difference.

Thank you Jeff. A catalytic equipped stove can burn lower (Btu's/kg/hr) and still burn clean than a secondary combustion (non cat) stove. Cat stoves need to be 550F or higher to maintain a clean burn of organic, inorganic and voc's. Secondary combustion stoves usually require 1100F or hotter.

Often, folks will point out you don't get as much flame on low in a catalytic stove as you do on a equal sized secondary combustion stove on a low burn. Factually, the low burns are apples and oranges as far as operating temps and burn rates.

Set two stoves side by side, one catalytic and the other a secondary combustion stove, use fairly identical fuel loads, set the burn rates equal at 1.25 or higher kg/hr (or faster) and watch the flames in both stoves. Both will be appealing.

The FACT that catalytic stoves can go lower is why low shoulder season heating is so easily done with a well engineered catalytic stove.
 
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BK's btu numbers are pretty honest.

At a low setting, you have a bunch of wood smoldering, not making much heat at all. Then you have the cat consuming the smoke from the smoldering wood. The same cat in the 20 as in the 30..... Not sure you would feel a real world difference.
Interesting. I had not considered the catalyst as the main heat source, but only as an emission control device that allowed the stove to operate at lower temperatures. The constant low heat production specs between the two models makes sense when catalytic stove performance is viewed in this way. I will probably stay with the 30 then if my installer goes along. Maybe I can take advantage of the higher capacity in the shoulder months if I can move the heat upstairs as Woody suggests. That would be a plus.

Many thanks for your responses.
 
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Interesting. I had not considered the catalyst as the main heat source, but only as an emission control device that allowed the stove to operate at lower temperatures.
I don't know if it's the main source, but on my stoves the stove top over the cat can be 500 or more while the sides of the stove may be only 375 or whatever.
 
I don't know if it's the main source, but on my stoves the stove top over the cat can be 500 or more while the sides of the stove may be only 375 or whatever.

Woody,

Yes indeed. When you slow down the burn rate, you can find the hot spot you mentioned, The reason is residence time. The slower the gases flow through the combustor, the more active or complete their destruction/consumption. Often, you will find low stove burn rates with cat temps upwards 800 degrees or more.

Draft, moisture content and other factors can influence the actual cat temp, but as a general rule, low and slow does create the situation you have observed. You're hired!
 
You're hired!
Alright! Maybe I can finally shake this "unemployable" label. ;lol Is it too early to put in a vacation request? ==c
 
Not if it's for fishing or hunting...but ask the other boss in your life! (If you have one)
 
Interesting. I had not considered the catalyst as the main heat source, but only as an emission control device that allowed the stove to operate at lower temperatures. The constant low heat production specs between the two models makes sense when catalytic stove performance is viewed in this way. I will probably stay with the 30 then if my installer goes along. Maybe I can take advantage of the higher capacity in the shoulder months if I can move the heat upstairs as Woody suggests.

That was an ah-hah moment. A real cat stove, a good cat stove, uses the cat only as the heat source during low burns. When you are choosing between the 20 and the 30 model you are not choosing two different sizes of engine, you are choosing between two different sizes of FUEL tank.
 
That was an ah-hah moment. A real cat stove, a good cat stove, uses the cat only as the heat source during low burns. When you are choosing between the 20 and the 30 model you are not choosing two different sizes of engine, you are choosing between two different sizes of FUEL tank.


Bingo...and to a small degree the amount of steel exchanger (larger surface area.)
 
Chris, is the Ashford 20 now shipping? Seems so, but it always helps to hear it from the source. Also, did you get the satin dark blue enamel into production yet?
 
...and to a small degree the amount of steel exchanger (larger surface area.)

I think this was part of the question in the OP. Do you feel a noticeable difference? My guess is not so much at low settings, but maybe more at higher burn rates?

Blaze King seems to be the only manufacturer offering the same stoves in different sizes. I'm pretty sure most ;) of us can't compare the different size BK stoves, since we buy one and stick with it.
 
Chris, is the Ashford 20 now shipping? Seems so, but it always helps to hear it from the source. Also, did you get the satin dark blue enamel into production yet?
No and no. The first castings for Ashford 20's are in house!! (Walla Walla).

We need to get the fire boxes into our production schedule.

Let me say up front, we are, as are our dealers, extremely busy. All this talk of EPA "banning" wood stoves has really created demand. Of course no such ban is about to happen.

I think we'll get them rolling (in all three colors) by early October if not sooner.

Again, being up front, many are already sold.

We have been pleased by the success of the Ashford.
 
I think this was part of the question in the OP. Do you feel a noticeable difference? My guess is not so much at low settings, but maybe more at higher burn rates?

Blaze King seems to be the only manufacturer offering the same stoves in different sizes. I'm pretty sure most ;) of us can't compare the different size BK stoves, since we buy one and stick with it.
The larger carrying capacity of the 30 will permit for longer burns of the comparable burn rate of a full 20 firebox. Footprint of space occupied seems to be another factor in many purchasing decisions.
 
We have been pleased by the success of the Ashford.

You should be. Clearly the best looking Blaze King and very nicely finished.
 
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