In our local for HVAC tech we only interview candidates that graduated with an associates degree and are in the top 5-10% of their class, occasionally we will take in non union techs like the original poster after testing. Most after taking the test think that since they have that degree and have been in the field for 3 to 5 years that they should start at least 3rd year or higher. After going thru the whole 5 year program, most admit that they really didn't know as much as they thought they did. Our HVAC training program is very comprehensive covering large chillers/boilers, ammonia, and DDC among other things. Now on the other hand to apply as a pipe fitter requires none of the above. We have some guys straight out of high school or the armed forces.