fireplace insert surround dimensions
We're planning to install a wood insert into our existing masonry fireplace. The brick fireplace has four square, grated openings (say 8x8"), one in each corner. I suspect this may be for air flow in addition to style, as you can feel warm air coming out of the top ones when a fire is going. All of the inserts we have seen have black surrounds of at least 8", and I have concerns about what this would do to the appearance of the fireplace.
What, exactly, is the function of the insert surround?
Is there a required minimum width?
Does the surround have to be metal?
Would blocking/covering the fireplace vents be an issue if the insert blower fan is managing the circulation?
Thanks in advance for your input!