[billybek]

HVAC/Refrigeration is a huge and growing industry.
It is primarily a service based trade although there are construction/install aspects of it.
Pros:
Work by yourself and get along with everyone...
Satisfying work. Stuff is broken when you arrive and running when you leave.
Limited amount of tools to purchase to survive in the industry.
Very rarely is a mechanic/technician in the same location two days in a row.
Very different areas in the industry from heavy industrial refrigeration/ammonia, large commercial centrifugal/screw chillers, commercial HVAC, commercial refrigeration/grocery stores, restaurant walk in boxes and residential heating/cooling.
Pay! For guys spinning wrenches, they make pretty good coin.
Cons
On call for emergency repairs/customer service.
Working in very cold conditions (outside for roof top heating applications and inside for refrigeration)
Working in very hot conditions (roof top applications and out door condensing coils/units.)
Stuff is heavy. Compressors/rigging/charging cylinders/recovery equipment/vacuum pumps.
Lots of opportunity to be injured or killed by many different things!