lennox ceramic blanket?

[qwerty]

I was looking at the Lennox website and noticed a reference to their wood burning inserts being lined with a "ceramic blanket" material that was developed by NASA and that has (purportedly) 10 times the insulating power of firebrick. Can anybody shed any light on this? Does it mean that the insert has this material on the inside of the firebox rather than brick? Does this add any value, or is it just some cheesey gimmick?

As a side note, I searched the forums and reviews for Lennox info but found few references. Some companies, like Jotul, VC, PE, Hearthstone, Quadrafire, Lopi, etc. receive mentions almost daily, but Lennox almost never. Is it not a quality brand? Too new?

Thanks.

 

[builderbob]

etc. receive mentions almost daily, but Lennox almost never. Is it not a quality brand? Too new?

Thanks.

@@@Lennox has been around as a heating/air conditioning company for a century (maybe longer), and I heard have always had a quality reputation in that area.

They have entered the fireplace/stove industry more recently through acquisitions---such as for example, Security Chimney Co. which makes BIS stoves/fireplaces, and which Lennox now markets still under the BIS brand but as clones also under the Lennox name. Security/BIS has long had a well-established quality reputation from what I have read.

In the 90's, I believe, Lennox had acquired a smaller stove company (forget the name) which had its own problems at time of acquisition, and that purchase did not work out. Lennox wised up and cut its losses on that. That process, I do believe, apparently caused some lingering hard feelings in the independent stoveshop industry.

From my own research, I have found for zero clearance woodburing fireplaces, Lennox offers hands down the best warranty in the business--parts AND LABOR for an extended period of years. Not the typical ONE year for labor of most other vendors. Lennox is a billion dollar company with the muscle to back up its words on product development, manufacture quality, and warranty promise.

I am purely a consumer, who has been reading, looking, and talking woodburning fireplaces and manufacturers of such. The above are the impressions I have formed.

I am sure any disgruntled shop owners will voice their opinions.

BTB

 

[BrotherBart]

The inserts sold by Lennox at the moment are the Country Stove line that they recently acquired. The ceramic blanket they refer to is used on top of the baffle bricks at the top of the stove to increase secondary burn efficiency.

The stove lining itself is bricks.

 

[jqgs214]

BB kinda like on the PE baffle??

 

[BrotherBart]

BB kinda like on the PE baffle??

I don't know about the Pacific but most of the PE line puts the blanket inside a stainless steel baffle. So does Century, carbon steel instead of stainless. Others like Quad put the blanket on top of ceramic fiber board.

 

[jqgs214]

YEP, Tthat what I got, blanket inside the s.s baffle.

 

[KeithO]

This would be the kind of stuff the blanket is made off. http://www.bgf.com/prodInsulSilcoApp.asp Costs about $10/lb. Not quite what NASA uses, but doesn't carry the price tag either... Aerospace / military use a lot of "wisker" products that are in fact very hazardous (like asbestos) but they are more concerned about more serious hazards like the SAM on their tail at Mach 2.5 or the ceramic tile falling off the shuttle at Mach 17....

 

[BrotherBart]

This would be the kind of stuff the blanket is made off. http://www.bgf.com/prodInsulSilcoApp.asp Costs about $10/lb. Not quite what NASA uses, but doesn't carry the price tag either... Aerospace / military use a lot of "wisker" products that are in fact very hazardous (like asbestos) but they are more concerned about more serious hazards like the SAM on their tail at Mach 2.5 or the ceramic tile falling off the shuttle at Mach 17....

Here is the guy making the blankets that insulate the nose of the shuttle. I ain't buying that there is asbestos or any other hazardous material in that ceramic blanket he is working on without a respirator.

 

[KeithO]

BB, the nose cone of the shuttle is in fact one of the special areas which have carbon fiber composite that can withstand over 2000f. If they put blankets in there it is all secondary insulation, not primary. Nasa has a ton of contractors. Saffil actually had a new primary heatshield made of laminated alumina fiber on Challenger. Unfortunately they blew up on the way out and the new heat shield was never tested. Since the disaster they decided not to try new ideas and so we had the second disaster with the damaged tile. Maybe if the first disaster hadn't happened, we would have had a new heatshield on Columbia and the second disaster might hot have happened either.

 

[KeithO]

Here are some thermal conductivity values for "insulating firebrick" although I think this is high quality stuff, not the kind of stuff found in our stoves : http://www.thermalceramics.com/upload/pdf/114-2.pdf

The ceramic blanket mentioned earlier has a thermal conductivity "k" value starting at 0.02 and going up to 0.4 (at 2000f) Thus at lower temperatures the blanket is 10x better than firebrick. As noted earlier, the blanket is behind the outside surface of the insert, where it can do the best job at reducing the surface temperatures to get close instalation clearances. To get better than these values is indeed getting into very specialized materials that are very expensive, generally hazardous and in most cases specially engineered for the specific application.

 

[Elderthewelder]

As mentioned Lennox aquired the Country Stove line, must have been real recent. I bought my Country insert last year and they were not affiliated with Lennox. Anyway that blanket sits on top of the upper fire bricks, between the bricks and the flue opening. Although the manufacturer says it helps retain the heat, my dealer/installer told me it was more for the epa rating, as it helps block the fine particles from going up the flue, he also said that he tells people to remove the blanket if they are having problems with draw, especially on 2 or 3 story houses. I removed my blanket (as did a friend of mine with a free standing Country stove) stove's heat our houses just fine.

 

[Gooserider]

Aside from suspecting that you and your friends may be VIOLATING FEDERAL LAW of the same sort that forbids removal of the cats from a cat stove, that is probably not doing all that much to help your draw. As I understand the way your stove is built, if it is properly assembled, the blanket should not be blocking the flue - it's an insulator, not a filter! However in some instances the blanket would shift during shipping and partly block the flue, which would hurt your draft.

The solution should be to reposition the blanket, not removing it.

Gooserider