Venting question

[timfromohio]

I posted earlier in the week asking for opinions on the Napolean 1150p cookstove. Well, I went ahead and bought the stove. Based on the 1100 reviews (I believe they share the same firebox design) we'll be very happy.

I have a question on the venting setup though - the stove will be placed against an exterior wall (not best placement I know, but the only option). Would it be better to go straight up, through the attic and out the roof or through the side wall of the house and then up? I think the appearance of up and out the roof would look better, but what about performance?

Thanks for any advice/opinions.

 

[Michael6268]

Performance is going to be better keeping it in the house and up through the attic. Keeping it in the house keeps the chimney warmer and therefore improving the draft. Also less "fluctuations" in the draft due to less temperature differences being in the house.

 

[BrotherBart]

For draft and heating performance both go straight up through the attic.

 

[nshif]

Plus straight up will save you money on the class A which can get pricey. You will need a few more fittings to get through the attic but I still think it will be cheaper, and look better in the end.

 

[Gooserider]

Straight up is also good because it eliminates the bends in the pipe - remember that each 90* bend is equal to a 5' reduction in your effective stack height. Since you are talking about going straight up into an attic, I'm guessing you have a nominal stack height of about 15-20' from the top of the stove - 6' for the room, 6' for the attic, a couple feet for the ceiling and roof, and 4-5' for the above the roof part. Most stoves want about 15' stack height to draw reliably, so this is would be a good setup, but not great. The Napoleon is top vent, so the out and up option would require two 90*'s, leaving you with an effective 5-10 feet, which is well below the optimal height.

IOW, go straight up, just like everyone else has suggested (and their reasons are also good...)

Gooserider

 

[timfromohio]

Thanks for the advice. Will go staight up and out.

 

[Corie]

Up and out is always better because then you also don't have to pay for a tee, which is almost always the most expensive piece of pipe you need. All the extra parts you'll need will be a round ceiling support collar, attic insulation shield and then flashing and a storm collar on the roof.

 

[webbie]

Just for the record, I have installed a number of chimneys both ways and never once had a draft problem with the straight up, but have had numerous callbacks on certain "out and up" the side wall. So there is a big difference, much of it because of the two extra 90 degree turns....less (IMHO) because of the fact it is outside.