How much heat am I loosing?

[southbalto]

Hey Everyone....

I put in a Jotul Castine last year and am having pretty good success with it this year. I purchased some wood late last year and it's really burning well for me.

I currently have the stove venting to the rear straight through the wall and into Class A (which is inside an exterior chase).

Do you all think I'd get a significant increase in heat output if I were to reverse the flue collar and vent it up 12" or so and then into the wall using a 90 degree elbow? I'd be using single wall pipe and obviously it would add some additional surface material inside the room. I love the look of the rear vent but if I'm going to see a 20-30 percent increase in heat output I'd probably make the switch......

ThoughtS?

 

[Pagey]

If it ain't broke, don't fix it. I'd leave it as is, personally. I depend on my stove for heat, not the stove pipe. I think getting 30% more heat off a little run of single wall would violate some law of physics. Someone please correct me if I am wrong, though.

 

[dispatcher101]

I have to agree with pyro. That is an awful lot of work for something that might not work. If you aren't struggling to keep you house warm and the stove is performing well I wouldn't risk it.

 

[North of 60]

Chimney/breaching is designed for exhausting not heating. Thats the stoves job.

 

[southbalto]

The stove is undersized for the house, but I knew that going in. If i'm diligent in keeping the stove fed I can keep the gas furnace off and the house in the low 70s.

This is the second season with the stove and the wife is starting to lean on me about putting the finishing material on the heat shield....I suppose I'll leave it as is. I'll get some pictures up next week.

 

[jotulguy]

On low burn rate the f-400 meets a 75% efficiency....that being said you couldnt gain 30% off a single wall run. There is only 25% left to gain and you will need all of it to help maintain your draft. The old non-epa stoves this is something i would say would have been of interest to try. But with the new epa stoves I dont think you will see any gain.

 

[Backwoods Savage]

You now have a rear exit, so it runs horizontal through the wall and then a 90 degree to go up. If you add another 90 degree you effectively shorten your chimney. Do that and you lose some draft which could very well negate anything you might possibly gain.

 

[southbalto]

On low burn rate the f-400 meets a 75% efficiency....that being said you couldnt gain 30% off a single wall run. There is only 25% left to gain and you will need all of it to help maintain your draft. The old non-epa stoves this is something i would say would have been of interest to try. But with the new epa stoves I dont think you will see any gain.

THis makes me feel better.

 

[HeatsTwice]

I read somewhere that you get 10% more heat from the stove for every 4 foot of chimney run in the house. Doing the math, 12" equates to 2.4% more heat. Not worth it.

 

[southbalto]

You now have a rear exit, so it runs horizontal through the wall and then a 90 degree to go up. If you add another 90 degree you effectively shorten your chimney. Do that and you lose some draft which could very well negate anything you might possibly gain.

Its been a pretty steep learning curve with this new stove. Growing up I had a 1978ish VC Defiant in the house.......load it up crack the door to get it rolling for the first 15 min then damp it down and it rolls for 4-6 hours. I struggled a bit getting the Castine up to cruising temp last year but this year its been a breeze with good wood.

I put a key damper in behind the stove last year. I felt for the 8 bucks it was at least a good safety feature...... The draft is so strong in the 24' stack that 20 min after start up, I need to fully close the key damper. Even with it fully closed the secondaries are going off like crazy.

 

[OhioBurner©]

I put a key damper in behind the stove last year. I felt for the 8 bucks it was at least a good safety feature...... The draft is so strong in the 24' stack that 20 min after start up, I need to fully close the key damper. Even with it fully closed the secondaries are going off like crazy.

Many have mentioned the Castine doesnt vent as well with the rear exit and really likes the top exit. But doesnt sound like yours has this problem at all so I wouldnt change what is working. Do you get smoke out the door when you open it?

 

[southbalto]

Yea, the stack really pulls the air.

I do get smoke in the room if I forget to open the key damper when I'm opening the door. So many variables with this thing but I'm getting there.

Split sizes, load sizes, key damper position, air controll settings.......

 

[r_d_gard]

Ok, so yesterday I broke down and purchased one of those infara red thermometer gun looking jobs. The kids have been playing with it everywhere (has a little laser on it). I, being a gadget kinda guy, used it to take temps on the stove. it was interesting to see that when the stove was fired up (VC Encore 2550 CAT) the griddle had hot a cold spots (my stove top thermometer is now in a "hot" spot. I also ran it across, nay zapped, the 6" exhaust/flue which I have running straight out the back. That pipe was riding at about 250-300°. All that said, draft, caused by heat and length of run may cool a bit and slow the upflow up the flue. You may have a problem or two with back puffing.

 

[firefighterjake]

If things are working well and you're keeping the house warm then leave things be . . . as Pagey said . . . the stove heats the place, not the chimney. I know Dennis and I both have exterior chimneys and going in I was worried about potential issues with draft (not a problem for you), creosote build up and some loss of heat that I would have got from the stove pipe being inside. More than two years later I can report that the draft has always been good, burning seasoned wood and at the proper temps = little to no creosote and if I do lose some heat I wouldn't know it since the house is plenty warm.

To sum up . . . If it ain't broke . . . don't fix it.