Heatilator is a brand of fireplaces.

I don't understand what you are referring to when you are calling something a "heatilator".

it's a heatilator in the sense that it takes in air through a vent, heats it and releases the heat through another vent. this is the general term i've had people refer to it as. this is a homemade "heatilator"

Can anyone answer the first question asked? Is it possible to close them up???

I have a similar set up and would like to close up these side vents so that I can build a nice fireplace surround around the firebox and drywall over the old brick at the top.

Heatilator was the first all-metal wood burning fireplace with an airspace between two heavy steel shells. There was an option to attach ducts to openings in the top and bottom of the steel shell so that air could move through it by convection. As I recall the vents were not required for safe operation but you should do some research to be sure.

so did anybody get information on being able to cover the air intake and outtake vents ---permanently? thanks