Jan:

Some microwave ovens have blower fans in them to exhaust air out of the microwave oven, as described in this installation manual:

http://www.mcappliance.com/document/KOT152UB.pdf

From skimming through that installation manual, it seems that the purpose of that blower fan is to ventilate the oven chamber itself. But, I fail to see the need to ventilate that air through ducting to the outdoors. Whenever I've opened the door of a microwave oven after heating something, the something was hot, but the air inside that oven chamber wasn't. So, why are we blowing it out of the house?

If someone in here knows why there's any benefit in ventilating a microwave oven, could they explain it to us all?