Zero clearance fireplaces are still regulated by the local building department. They tend to be conservative about risk management. A zero clearance wood burner is a box in a box, like a double wall flue. Most inspectors don't give hoot what the manufacturer says, they will still make you maintain the 2" minimum to combustible materials from the firebox and all its parts. Gas only fireplaces are different. Heat does not radiate form them as much, most goes right up the flue. Sort of a waste. Look at Fireplace Xtrordinaire for heat circulating wood and gas fireplaces...most other manufacturers probably have them...just those are the ones the architects I've been working with are specifying.

@Ironwood Builders
Tanks for the info - i learned something new today :))))

Thanks for the info! I am going to check out Fireplace Xtrordinaire right now!