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[BoilerHouse]

My standard ncb 175 I think was around 52-54 last year when I ran it... 

I think my heatmaster 5000e is likely close to 60 based on some quick calculations, very similar to what your 325g would come in at...

Could you explain how you do the calculations please? I would like to run the numbers on my own stove.

Here is a link explaining how to do a DIY efficiency test that should at least get you in the ball park.

http://woodheat.org/bob-report.html

[TheBoiler]

Boiler, it could be that low it's just hard enough to get folks to beleive there around 40.  Ridges cb 5036 was around 48% with the best of products he could buy.  Then if you through in a 25% reduction based on 1/2" vs 1/4".  That would bring it down to the range you are talking about.

We worked his out by looking at the previous years Propane use, Propane saved and approx amount of wood burnt.

There are a lot of variables but it sounds about right. He gets through a lot of wood but most of it is scrounged/donated. So buying a bigger/more efficient one makes no sense.

We also looked at another friends CB E Classic. Difficult to get a good number, we think about 50%.

Interesting link, sounds more accurate.

[powerstroke]

This link shows the same guy modifying his furnace the next year by completely lining it with firebrick.  He said it made a huge difference in efficiency!  I thought though that making the firebox "thicker" was supposed to cut down on efficiency?  I thought that it would just reflect the heat and send it right up the chimney?  Surely making the firebox an inch or more thick would make it like 80% less efficient.................(sarcasm intended)

http://woodheat.org/report-bob-modify.html

[martyinmi]

powerstroke,
   Bob actually turned his conventional OWB into an up draft gasifier.... of sorts. His metal that was jacketed by water prevented him achieving gasification prior to the addition of the high temperature refractory board he used in his conversion. He can now achieve temps well over 1000*(probably between 1000* and 2000*) by burning his smoke and passing it by the full length of the ripple top of his boiler. That's where he gains all the extra efficiency. I think the biggest function of the firebrick was to serve as a place  set the shelves on(I can think of a few other functions, but that's another topic). You can see it's only used on the bottom and sides. The Alumina fiber board was used for the shelves. Some brands of that product will withstand temps in excess of 3000*.

[powerstroke]

 Yeah I seen that Marty.  That is a pretty nifty little idea!  I wonder if it does gassify very well.  I guess with enough air it could work pretty well. ( obviously it is)  It just seems that only having the heat on the roof of the firebox would lead to a massive hot spot and tend to boil the hell out of the water in that small area if that was really the only heat being utilized. Heck who knows.

[woodfuel]

Powerstroke, sorry every one rips on the thickness of shaver's boilers being less efficient. Personally, i think that free wood is the most efficient and don't care about the owb efficiencies. U may be the last one laughing when our fireboxes rust through and you have your thick steel shaver lasting a lifetime!

[Scott7m]

Yea Marty summed it up, he changed the whole function of the stove, the refractory increase temps tremendously and burn gases normally wasted

[TheBoiler]

This link shows the same guy modifying his furnace the next year by completely lining it with firebrick.  He said it made a huge difference in efficiency!  I thought though that making the firebox "thicker" was supposed to cut down on efficiency?  I thought that it would just reflect the heat and send it right up the chimney?  Surely making the firebox an inch or more thick would make it like 80% less efficient.................(sarcasm intended)

http://woodheat.org/report-bob-modify.html

I am going to send this to my friend, this guy effectively converted his standard OWB into a Gassifying OWB without that much investment, cutting down on his wood usage and emissions significantly. I wonder what it cost him to do it?

[jimr]

Shaver Furnace is proud to announce that the Shaver Pro Series 165
has been tested and certified to be 75% efficient or better and this means  that you will burn less wood than others!
 
cut & pasted from there add on E-BAY

[Scott7m]

They also have an add claiming there regular boiler is a gassification furnace because of the drop chimney design...   Nothing but a joke

[lugnut]

So is the Shaver company the ONLY culprit in claiming something they are not?  By the way, NOT all of us that have Shavers opted for the thicker firewall.  I went with the standard firewall thickness because if there is/was any kind of failure, it would fallback on their warranty...provided they would still be in business.

Guess it's time for me to compose the letter I've been meaning to send Mr. Billy Shaver.  I WANT to know exactly what is going on and I will c/c my letter to the BBB of Arkansas.

Lugnut

[Bull]

Lug, I'm sure all companies mislead people but some more than others. Your Shaver will probably be around for a long time and just use a little more wood than some.

[martyinmi]

Bull is right, Lug.

ALL OWB manufacturers lie about their products to some extent.


"Honest OWB Manufacturer" is an oxymoron.

Yours will get more and more efficient every year as the burn chamber erodes away, but you'll still be heating with it. The rest of us will be on our 10th patch job before yours springs it's first leak!

[willieG]

Yours will get more and more efficient every year as the burn chamber erodes away, but you'll still be heating with it. The rest of us will be on our 10th patch job before yours springs it's first leak!

now i feel a whole lot better  about the 7/16 fire box of the ole silver bullet!

[swede]

I have never believed the 75% claim and don't really care.  I'm using less wood in the Shaver than my buddies Heatmor and Centrals and less wood than our old Wilkening home heater used each season for the last 25 years.  The rugged simplicity of the unit appeals to me and it works well to heat our home and hot water.  Total costs were under 4500 for stove and complete install.  How can a person beat that?