I doubt a product made of sheet metal alone would be efficient enough to get up to that temperature. 

@Mike CalabreseThe only issue you need to worry about is if the coal celler still has an access point, usually a good-sized metal hatch that was used to deliver coal to the room from the outside.

there is nothing wrong with it, most microwaves have that option and do not have to be vented out, even though as a contractor i prefer them to vent out. if the existing pipe already vents out, which it probably does if there is a pipe in the cabinet already. what you would have to do is unscrew the 2 or 3 screws in the top cabinet that screw down into the microwave ( if not there then there may be 2 bolts in the front of the unit behind the cover that have to be loosened) that will loosen the microwave, then its a matter of taking the screws out that hold the fan at the top back, pull the blower fan out and change the direction so that it faces up, screw the fan back to the unit and put the microwave back up and bolting it. check to make sure the fan connects to the duct work, if not, add a piece of sheet metal to connect and seal that joint. btw you may want to unplug the microwave before doing so, just for safety reasons.

Anyone flipping old houses in Little Rock and surrounding areas, I will take any old metal kitchen cabinets you're getting rid of off your hands, and maybe light fixtures, sinks, etc. too.

The two car garage is actually a metal garage on his property and he thinks he has an acre and a quarter on his side which if the house comes with an acre doesn't add up to 2. 

Think about it like this-if it was a good deal and met all the rules of thumb at 3.5% down there’s no way an investor wouldn’t snap it up and make a killing with a conventional investor loan or alternative financing. 

I have spray painted ugly metal windows or sliding doors with a quality white paint.

That means they have a wood frame underneath versus the metal frame and they are typically built with 2X6's versus 2X4's.

I think this might be a better choice that doing metal bars on the windows for the most basic reason it looks better.

You may have issues with residue in the hvac coils or vents.