BK Ashford 20.2 vs 30.2 minimum btu output

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10moreyears

Member
Mar 21, 2008
16
S. Cal. Mountains
I have a question about realistic minimum btu outputs for the BK Ashford 20.2 vs 30.2. The data on the BK website suggests that there is minimal difference between the two (~11k btu vs. ~12k btu). The reason that I am asking is that the house the woodstove will be going into is relatively small (~1300 sq ft) and highly insulated and will not have a heat load more than 12k btu until the temperature is below the 99% heating design temperature (5F; although record cold is -30F). That means no continuous burns most of the time if ~11-12k btu is a realistic lowest burn rate. I would be burning mostly Douglas Fir with some Grand Fir and Western Larch. Does anybody have any data on the lowest realistic btu output? Of course, the house will also have a minisplit heatpump, but the plan is to use a woodstove during the middle of the winter when solar PV output is lowest.
 

begreen

Mooderator
Staff member
Nov 18, 2005
93,188
South Puget Sound, WA
You might want to consider a lower output stove like the Woodstock Fireview. It has an output of 7,606-46,460/hr (per EPA tests).
 

jalmondale

Member
Dec 16, 2021
113
NY
I just got a Fireview this year, and can confirm that it can dial way down - we've had a few spring-like days in the 50s recently, and the house has not overheated. When temps are in the 20s/30s, I reload 3 times a day, and when they're in 40s/50s, I can get away with just 2 reloads. I suspect the soapstone-as-thermal-flywheel helps a lot with that.
 

10moreyears

Member
Mar 21, 2008
16
S. Cal. Mountains
I just got a Fireview this year, and can confirm that it can dial way down - we've had a few spring-like days in the 50s recently, and the house has not overheated. When temps are in the 20s/30s, I reload 3 times a day, and when they're in 40s/50s, I can get away with just 2 reloads. I suspect the soapstone-as-thermal-flywheel helps a lot with that.
Thanks for the info. Can you confirm that it is rear exhaust only? If so, that probably rules it out.
 

Highbeam

Minister of Fire
Dec 28, 2006
19,697
Mt. Rainier Foothills, WA
Thanks. The Keystone apparently only goes down to ~10k btu, but that's still less than the BK woodstoves.

You don’t need to continuously run the stove. In my situation, for a large part of the heating season like 6 months, I have to let the fire die each day. Relights are easy and fast with dry fuel.

Don’t worry about the bottom end. Any stove can go to zero if it’s too warm.
 

10moreyears

Member
Mar 21, 2008
16
S. Cal. Mountains
You don’t need to continuously run the stove. In my situation, for a large part of the heating season like 6 months, I have to let the fire die each day. Relights are easy and fast with dry fuel.

Don’t worry about the bottom end. Any stove can go to zero if it’s too warm.
Thanks for the comment. I understand that. In my experience with an old BK (prior to catalytic stoves), it's easier to burn continuously than to relight each day. However, it looks like non-continuous burning will likely be required most of the time. The floor will be an insulated concrete slab without any carpet, so a fair amount of heat can be stored in the floor, and I can tolerate some fluctuations in temperature, so I'm sure it will all work out. I just want the perfect stove for my situation with good aesthetics, low emissions, long burns, and a range in output from ~5k btu to ~30k btu... we can all wish. :)
 

stoveliker

Minister of Fire
Nov 17, 2019
4,353
Long Island NY
5k BTUs is tough with any stove (continuous). I don't like restarts either, so I have a BK - not (!) necessarily for the low end (as begreen noted, there are ones with a lower output), but for the *constant output* on the low end, and for the *range* of outputs possible.

Why not have a minisplit for those days, and a stove for when you need 15 k BTU or so?

Oh, and aesthetics - is in the eye of the beholder (aka the significant other)... :)
 
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10moreyears

Member
Mar 21, 2008
16
S. Cal. Mountains
5k BTUs is tough with any stove (continuous). I don't like restarts either, so I have a BK - not (!) necessarily for the low end (as begreen noted, there are ones with a lower output), but for the *constant output* on the low end, and for the *range* of outputs possible.

Why not have a minisplit for those days, and a stove for when you need 15 k BTU or so?

Oh, and aesthetics - is in the eye of the beholder (aka the significant other)... :)

Thanks for your comments. I will have minisplits that will be able cover the heating load down to about -15F (which is enough for most winters). However, I want to use the wood stove to provide heat during the winter months which have low solar PV production even east of the Cascades in the Pacific Northwest.

The other problem is that on average only ~4 days per winter will have a daily heat load more than 12k btu/hr, and those days would require a maximum of ~18k btu/hr. My problem is that my house will be too small and efficient. However, I'll take the inconvenience of daily fire restarts over using more energy, including the energy required to cut, split, and stack the wood by hand. :)

Yes, aesthetics is very much in the eye of the beholder!
 
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Highbeam

Minister of Fire
Dec 28, 2006
19,697
Mt. Rainier Foothills, WA
Thanks for your comments. I will have minisplits that will be able cover the heating load down to about -15F (which is enough for most winters). However, I want to use the wood stove to provide heat during the winter months which have low solar PV production even east of the Cascades in the Pacific Northwest.

The other problem is that on average only ~4 days per winter will have a daily heat load more than 12k btu/hr, and those days would require a maximum of ~18k btu/hr. My problem is that my house will be too small and efficient. However, I'll take the inconvenience of daily fire restarts over using more energy, including the energy required to cut, split, and stack the wood by hand. :)

Yes, aesthetics is very much in the eye of the beholder!

How about this weird idea….. depending on price of wood, it might be cheaper to use your mini splits to cool the home when your wood fire makes too much heat for conditions.
 

stoveliker

Minister of Fire
Nov 17, 2019
4,353
Long Island NY
Hm, but that is the worst for resource conservation...
 

10moreyears

Member
Mar 21, 2008
16
S. Cal. Mountains
Could also open a window.
Yes, there will be a motorized awning window in the side wall of the cathedral ceiling that could be opened to dissipate heat without making the living space uncomfortable. I would certainly do that before running A/C. However, wasting energy goes against the grain, so I don't think that is likely to be used very often.
 
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begreen

Mooderator
Staff member
Nov 18, 2005
93,188
South Puget Sound, WA
First, congratulations on the energy efficiency achievements. They pay off in the short and long term. For the supplemental heat, the Fireview looks like a good fit if the goal is long heat, but if the house holds onto the heat well, then a small stove that gets loaded more frequently might be more than adequate. I'm thinking something like a Morso 2b or Squirrel stove.
 
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10moreyears

Member
Mar 21, 2008
16
S. Cal. Mountains
First, congratulations on the energy efficiency achievements. They pay off in the short and long term. For the supplemental heat, the Fireview looks like a good fit if the goal is long heat, but if the house holds onto the heat well, then a small stove that gets loaded more frequently might be more than adequate. I'm thinking something like a Morso 2b or Squirrel stove.
Thanks for the information on the Morso stoves; the Squirrel looks interesting. I agree the Fireview looks like a good option for btu output and would allow continuous operation up to ~32F which would be most of the winter. Unfortunately, a rear vent doesn't easily fit the house design. It could be done but would take space out of the living room.
 

10moreyears

Member
Mar 21, 2008
16
S. Cal. Mountains
First, congratulations on the energy efficiency achievements. They pay off in the short and long term. For the supplemental heat, the Fireview looks like a good fit if the goal is long heat, but if the house holds onto the heat well, then a small stove that gets loaded more frequently might be more than adequate. I'm thinking something like a Morso 2b or Squirrel stove.
In looking at the manual for the Fireview, it might work. Question: The manual shows an example of a 90 degree elbow at the rear vent and then stove pipe straight up to the cathedral ceiling support box (see attached). I had thought that this configuration might not be stable due to weight of stovepipe on the elbow, but of course all of the stovepipe connections would be screwed together. Does anybody have experience with this kind of setup with the cathedral ceiling height of ~20ft where the support box goes through the roof?

Woodstock Fireview Screenshot 2022-03-06 190257.png