It seems that many members feel a blower is a must or a near must for a Zero Clearance wood burning fireplace. I just installed a Kozy Heat Z42 and after reading some posts on here and thinking about it decided to get 1. The dealer here has been excellent and is very knowledgable. They state that the blower will not increase the BTU output of this unit. That the blower is useful if you want the heat from the unit to travel a substantial distance. The way this thing works is that air is brought from the bottom of the unit and heated as the air comes up through the air space surrounding the firebox. The blower pushes that air out at a velocity. (these are not quotes from dealer) I also see that Kozy Heat states that the blower is optional. I just started burning this thing 2 days ago so I'm no expert, but so far when I get this baby running well it heats my house great, all most too great. It's 80 degrees upstairs and about 72 downstairs right now. I'm thinking I may have an easier time heating than some; my home is a fairly tight modular and the fireplace is right in the middle of the house and at the base of the staircase.