Is it OK to have an air conditioning vent above a kitchen cabinet?
Sorry I don't have enough points to comment yet so have to put this reply in the answer. 

I had a vent coming out under the cabinets in the kitchen of my house for 20 years with NO PROBLEM (i.e. at the floor level where the kick-plate is). This wasn't even ductwork under the cabinet, but rather the vent exhausted into the frame under the cabinets, which then vented out the kick-plate.

My system would push out gas fired hot air in winter, and integrated AC in summer. He had a HRV. 

No splitting in the cabinets, no peeling of the veneer, no warping of the frames. 

I'd say go for it.