Midwestern US

Humid continental — pre-WWII brick chimney stock dominates.

Humid continental — heavy heating season.

Cold lake-effect winters around Chicago — heavy creosote.

Heavy snow load and a long heating season drive the crown failures inspections turn up here.

Severe winters produce the heaviest creosote loads east of the Mississippi, the kind a graded sweep catches.

Deep-freeze winters shift flue tile and open chase-flashing gaps that a camera scan documents.

Humid continental — heavy farm-region wood-burning.

Humid continental — mixed urban + rural patterns.

Hot summers + cold winters — heavy freeze-thaw.

Continental — wide temp swings.