efficiency

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
  • Hope everyone has a wonderful and warm Thanksgiving!
  • Super Cedar firestarters 30% discount Use code Hearth2024 Click here
Jan 10, 2022
131
Northeastern Vermont
Does anybody have any actual data on how efficient (inefficient) a completely unsealed antique stove is?

EPA says for new models:
Catalytic stove: Average 78% (range 63% - 84%)
Non-catalytic or secondary combustion stoves: Average 71% (range 60% - 80%)

I have two catalytic stoves in the newer section of my house.
But I have three antique stoves in the old section of the house, which are just used as needed.

Thanks!
 
I'm not sure that question is answerable, given the vagueness in "completely unsealed".
The efficiency is (in part) dependent on the leak (in) rate. So the size of the "leaks" (not really an appropriate name as it was designed in this way) matters. And that might very well be very different for different old stoves.
 
I'm not sure that question is answerable, given the vagueness in "completely unsealed".
The efficiency is (in part) dependent on the leak (in) rate. So the size of the "leaks" (not really an appropriate name as it was designed in this way) matters. And that might very well be very different for different old stoves.

Yes, they are primitive stoves... just iron boxes with no baffles.
I guess I am wondering about where they might range in the spectrum between an open fireplace and a modern sealed wood stove.
 
I don't know :)
My gut says around 60 pct or so. Better than fireplaces (when they run ;-) ) but not as good as a poor sealed stove in upper 60s lower 70s.

I presume bholler knows better.

On the other hand, what about a cast iron classic looking more modern stove in your classic home? Saves wood, the environment, and may still look good with the surrounding - even if not authentic.
 
Honestly it will really depend how often you will be using them. If it's a dozen times a year or so tear them down clean them up and reseal them. So they are safe to use. If it's much more than that I would be looking for something more efficient
 
I don't know :)
My gut says around 60 pct or so. Better than fireplaces (when they run ;-) ) but not as good as a poor sealed stove in upper 60s lower 70s.

I presume bholler knows better.

On the other hand, what about a cast iron classic looking more modern stove in your classic home? Saves wood, the environment, and may still look good with the surrounding - even if not authentic.
I have a small Jotul (cast iron) as well as a Woodstock Fireview (soapstone) stove in the main brick part of the house. This is where the living room, bedrooms, and office are. They are both catalytic stoves, and this side of the house is kept heated.

The antique stoves are on the other part the house (made of wood, and it is like a separate house joined to the brick house). I don't really need to update the stoves because:

1) One of them is in my attic... with my drums, etc. There is no heat in that room at all. It is a big iron stove and I would just fire it up occasionally when friends are over. It is sort of special because it is very local, and stoves are not made here anymore. Normally the room is left unheated.

2) There is a tiny stove in the kitchen. They call it a "morning stove". It heats instantly... and is perfect to use when we wake up, or just arrive from out of town, or while we are in there cooking. It is so comfortable and functional... and good in the shoulder seasons too.

3) The third stove is a very pretty one (but maybe the least functional). This fits in the dining room fireplace. I am trying to decide if I will use that stove or use the open fireplace. Either way, it would be burned very occasionally during some dinners.

So as you see, the antique stoves would be burned just occasionally. The rooms there are left cool when not in use.

Information on the stoves is very hard to find. I sent a message to "Efficiency Vermont" program, as they have some nerds that might be able to point me toward some studies.

Honestly it will really depend how often you will be using them. If it's a dozen times a year or so tear them down clean them up and reseal them. So they are safe to use. If it's much more than that I would be looking for something more efficient
I could take apart the one in the attic... but the other two are open as part of the design. It is not that they became unsealed.... they are just primitive stoves.
Although.... the one in the kitchen is probably my favorite stove in the house (functionally).
 
I have a small Jotul (cast iron) as well as a Woodstock Fireview (soapstone) stove in the main brick part of the house. This is where the living room, bedrooms, and office are. They are both catalytic stoves, and this side of the house is kept heated.

The antique stoves are on the other part the house (made of wood, and it is like a separate house joined to the brick house). I don't really need to update the stoves because:

1) One of them is in my attic... with my drums, etc. There is no heat in that room at all. It is a big iron stove and I would just fire it up occasionally when friends are over. It is sort of special because it is very local, and stoves are not made here anymore. Normally the room is left unheated.

2) There is a tiny stove in the kitchen. They call it a "morning stove". It heats instantly... and is perfect to use when we wake up, or just arrive from out of town, or while we are in there cooking. It is so comfortable and functional... and good in the shoulder seasons too.

3) The third stove is a very pretty one (but maybe the least functional). This fits in the dining room fireplace. I am trying to decide if I will use that stove or use the open fireplace. Either way, it would be burned very occasionally during some dinners.

So as you see, the antique stoves would be burned just occasionally. The rooms there are left cool when not in use.

Information on the stoves is very hard to find. I sent a message to "Efficiency Vermont" program, as they have some nerds that might be able to point me toward some studies.


I could take apart the one in the attic... but the other two are open as part of the design. It is not that they became unsealed.... they are just primitive stoves.
Although.... the one in the kitchen is probably my favorite stove in the house (functionally).
Can you post some pics?
 
  • Like
Reactions: clancey
I think it would depend a lot on how it is burnt. "completely unsealed" would still have some form of dampers/vents to regulate air flow, or ideally a damper. Even optimizing those settings could change the apparent efficiency by a huge magnitude.

When I first started burning, the rental house I was in had this weird 1970's box fireplace type thing. Basically a steel box with bi-fold glass doors all across the front. It was pretty much 'unsealed' considering all that glass and doors weren't really gasketed or provide any real air control. First several burns were a roaring fire, but you'd freeze to death 5 feet from the thing. The air and heat were ripping so fast up the flue and taking a good deal of house air with it.

I experimented with closing the damper about 2/3 the way, and it really transformed the 'fireplace' into something I could heat the house with. Since there was no way to control the inlet air, the damper was all that was available. But I could turn it to the point smoke would leak out the doors, then open just a bit and that would help the box get much hotter and stop some of the room air getting needlessly sucked out.

So bottom line, if you can burn under ideal conditions, I wouldn't be surprised if it could get into the 50-60% range. If it is truely just an open box, it might be half that, or even energy negative considering how much air is going up the flue vs heat to the room.
 
  • Like
Reactions: bholler and clancey
I see what you mean. I don't know why the number is important to me anyway.

The kitchen stove is perfect for its application and I suspect the attic stove will be also (these areas are not heated constantly and only used as needed). My two EPA stoves are good in their application in the main part of the house which IS heated constantly.

I guess I am still thinking about the dining room and whether it will be an open fireplace or use the antique stove.
I assumed it would be a stove, but the fireplace drafts and performs so well in the original brick chimney (I just tested it the other day).

The dinging room stove will need a liner if I go that route. Now don't freak out on me for this question:
We all know that "slammer" installs of inserts, for example, are no good.
But... if this old antique free standing stove blows smoke right up the fireplace flue.... is that really any WORSE that just burning the open fireplace? I mean, I will get to the liner when I can (if I use the stove). But... as of right now... it is an open fireplace anyway that accepts wood directly in the fireplace. The antique stove is wide open (holes by design). Isn't this at least a bit better than the open fireplace? Or is there some factor that I am not considering?
 
Can you post some pics?

This is the little kitchen stove that I like so much. Incredibly, it has been the most functional and enjoyable stove in this house.

[Hearth.com] efficiency [Hearth.com] efficiency
 
  • Like
Reactions: D. Hermit
The attic a stove is in a separate post entitled "Antique stove from Barton, Vermont ??"

And then below is the very old stove that fits in my dining room fireplace (instead of burning wood in open fireplace). I just have it out in the barn because I was doing some work on it (and testing it)

[Hearth.com] efficiency [Hearth.com] efficiency
 
WIth respect to your favorite stove, you know you are in trouble when you can see the glow of flames around the door;) Built for heat, not efficiency.
 
Those EPA stoves are scary hot enough as built.....
BTW is yours a flip phone or is the room full of smoke in your pics?
How are they scary hot? Plenty of pre EPA stoves glowed pretty regularly
 
All the photos? No, there is no smoke. Probably the lighting (or the change to an annoying iphone). I am going going back to flip phone
View attachment 290857
My pics always look like that. The lense on my phone is usually scratched up a week or 2 after I get it. And yes I hate i-phones as well.