90° Elbows and Flue Temp

[SpaceBus]

Does the type of elbow matter? My single wall has a 90 elbow that is two pipes welded at 45's. Would it help my flue temp stay higher with an elbow with more radius? I understand that a more radiused elbow would increase gas velocity, but I don't know if this affects temperatures.

 

[begreen]

The best solution to keep higher flue temps would be to use double-wall stove pipe using a pair of 45s with an offset so that the top 45 is right at the thimble.

 

[SpaceBus]

The best solution to keep higher flue temps would be to use double-wall stove pipe using a pair of 45s with an offset so that the top 45 is right at the thimble.

Then I will save my pennies and do that next year rather than mess with additional single wall stuff.