Coalpail.com Forum

Some thoughts on How Plymouth Coal Stove works design Chubby Stove has an "edge up" on competition.
1. The shaker design. Being Round ( No Dead spots in corners) and NOT "GRINDING" up the coal that COULD, or IS Burning, saves the coal for a Complete burn. While a under the grate" poking" is required, the amount of Coal Pieces in the ASH that are burnable are about 1/2 of a similar BTU "Grinder" grate Stove.
2. The "Pot" design. We Know Coal likes to be "Snuggly" to burn right, and while the Chubby easily provides a great environment for this, it does it
WITHOUT Firebricks. So what difference does that make? For heat transfer , its a BIG deal on a small stove. Without Bricks, the heat can transfer to the sides of the stove and OUT to the air Much easier. Turning on the blower proves how easy it is to get heat out of the Coal Chubby. Meanwhile the heat from the sides, comes up and HITS the Stove top, which hangs over the side. THIS is a heat transfer device. Like on some old stoves with many "Rings" or platforms, they all cause a small circulation pattern of heat to get Removed from the stove when the heat has to "go around" the "ring or Lid, to go up. This adds to the Chubbys' efficiency.
3. With Blashak Nut coal, I consistently get a white "powder" and very few pieces in my ash pan, and after washing those I see they are Not burnable coal. This 95% Powder makes a lighter pan to empty.
4. Not getting into %'s of efficiency, but once the draft is dialed in and and the coal is burning and settled in. I use about 29-30 lbs a day during winter.
Same BTU stove in a Keystoker, or Harman and I would be at 45-50 lbs to do the same job. Bigger grates on these has much do do with that as you MUST burn More at once with a square stove.

Chubby heat can't be beat

Formulabruce wrote:<snip>
4. Not getting into %'s of efficiency, but once the draft is dialed in and and the coal is burning and settled in. I use about 29-30 lbs a day during winter.
Same BTU stove in a Keystoker, or Harman and I would be at 45-50 lbs to do the same job. Bigger grates on these has much do do with that as you MUST burn More at once with a square stove.

chubby flames.jpg

That's 34,800 to 36,000 BTU/day for one and

54,000 - 60,000 BTU per day for 2nd

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heatloss.html

A sliver of info on house-loss BTU for southern house....

What would one expect for your house? Depends on many factors...but what would an ideal house BTU/day use be expected (for a given difference in outside v. inside temps)??? Anyone have idea?

Id like to have a little coal stove in my big living room someday.
I've got my eye on a Chubby... Such a cute little stove. I like the antiques too but not sure if the antique would really go with the house where the Chubby is more modern looking. Do they make a Chubby with a nice fire view?

Lightning wrote:Do they make a Chubby with a nice fire view?

Why yes we do... The "Fire View" door is standard on all new Chubby's. You can see the "Fire View" door on our website @ http://www.chubbystove.com or just take a peak at FORUMALBRUCE's avatar.

Other than the dog greeting me when I come home few things are as nice as seeing the warm glow of the coal fire in my Chubby when I walk in the door.

davidmcbeth3 wrote:

Formulabruce wrote:<snip>
4. Not getting into %'s of efficiency, but once the draft is dialed in and and the coal is burning and settled in. I use about 29-30 lbs a day during winter.
Same BTU stove in a Keystoker, or Harman and I would be at 45-50 lbs to do the same job. Bigger grates on these has much do do with that as you MUST burn More at once with a square stove.

chubby flames.jpg

That's 34,800 to 36,000 BTU/day for one and

54,000 - 60,000 BTU per day for 2nd

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heatloss.html

A sliver of info on house-loss BTU for southern house....

What would one expect for your house? Depends on many factors...but what would an ideal house BTU/day use be expected (for a given difference in outside v. inside temps)??? Anyone have idea?

Its very hard for me to get a real accurate number on the "R" value at my house. Its about 1,500 Sq ft. and 2 story built in 1862 ( Lincoln was President) It HAD no water or electricity when built and went 40+ years before those were installed. Some insulation blown in through clap boards 60 years ago has settled in the walls. I do have new windows.
That said, Its impossible to compare a Coal stove to a home heating furnace, and here is why. The BTU/day number is a 24/7 number as the Coal is ALWAYS on. An oil furnace has to play catch up, which gets difficult when it gets colder in an older house. The amount of BTU generated by Coal on paper usually does NOT equal what people "get out" of their stove. For example, IF you use a baro damper, you will suck heat out of your living space and Up the chimney...< If not, youll need to keep an Eye on your draft as winds and barometric pressure can affect usage.
Even with Coal Always on, it uses Less dollars than oil does, and can help dry out a damp house too.
Ideas are 20K BTU on days 20-40 degrees, and 45K on days 0-32 , and 65K on days -20-+10 For MY old house ....With Minimal Wind (<15 mph)
Right now I am in the 18-40 range

Formulabruce wrote:That said, Its impossible to compare a Coal stove to a home heating furnace, and here is why. The BTU/day number is a 24/7 number as the Coal is ALWAYS on.

This is something may don't understand FB. A hand fed coal stove is a constant heat source. No "peaks and valleys". Just smooth even heat that is very adjustable depending on what the heating need is.

ONEDOLLAR wrote: Why yes we do... The "Fire View" door is standard on all new Chubby's. You can see the "Fire View" door on our website @ http://www.chubbystove.com or just take a peak at FORUMALBRUCE's avatar.

Other than the dog greeting me when I come home few things are as nice as seeing the warm glow of the coal fire in my Chubby when I walk in the door.

Yeah wow, beautiful stove

yup!

Formulabruce wrote: 4. Not getting into %'s of efficiency, but once the draft is dialed in and and the coal is burning and settled in. I use about 29-30 lbs a day during winter.
Same BTU stove in a Keystoker, or Harman and I would be at 45-50 lbs to do the same job. Bigger grates on these has much do do with that as you MUST burn More at once with a square stove.

Which square stoves have you used in your home?

Rob R. wrote:

Formulabruce wrote: 4. Not getting into %'s of efficiency, but once the draft is dialed in and and the coal is burning and settled in. I use about 29-30 lbs a day during winter.
Same BTU stove in a Keystoker, or Harman and I would be at 45-50 lbs to do the same job. Bigger grates on these has much do do with that as you MUST burn More at once with a square stove.

Which square stoves have you used in your home?

Harman mark II. I do like that stove a lot, and would easily use it to heat a bigger place, maybe a garage, But this thread is about efficiency, and the Harman Shaker kicks out pieces of coal that could be burned. In a bigger heating situation, it wouldnt matter as much. I have screened the ash from the Harman and used the fines for re starting a fire in late fall usage

Chubby does make a very good stove, highly efficient for such a small attractive stove.

There is far more to efficiency than turning coal into a fine powder ash.

lsayre wrote:There is far more to efficiency than turning coal into a fine powder ash.

While true, it proves that fuel isnt wasted and tossed out. Complete burn IS part of efficiency !

A big part of the overall efficiency of a stove is not to waste the heat. The Chubby has outstanding control and can be idled down while away from home or when the weather warms up briefly. Opening windows in the winter because your house got too warm is very wasteful, yet lot of people do it and brag about it even.