Venting configuration question

My installer said code required the exhaust to be a mininum of 18 inches from siding. I have seen homes in my neighborhood with flush mounted terminations and large soot stains on the house. I'm pretty sure that those stoves weren't operating efficiently but why risk it!

I agree with both the previous posters. First check your manual and any local codes. Make sure you meet those specs as a minumum. Then go with 18" rule to keep as much blowback soot and residue of the siding.

It looks to me that if you measure from the siding to the end cap on your short setup in that picture. You are pretty close to 18 inches. The longer run looks to be a little excessive in my eyes. Maybe all you need is a 6" piece of pipe to meet the the specs, and then it wont stick out so far.

Duravent used to call for a 12 beyond the building, not sure what the manual says, but the elbow gives you 5.5" of length to the center, plus 2.25" to the outside of the pipe, plus the bracket set at two inches. That gives you 9.75". then you have to add the cap. the old style caps like you have gave you another 3". that would give you 12.75" from the wall to the first part of the exaust to the cap. Pellet Pro from duravent only requires a 6" horizontal offset from the cap to the siding, but your stove manual takes precedence over the pipe manual.