Professions that require hands-on talent, such as electrical repair, plumbing and HVAC maintenance, fall under the category of skilled trade. You might wonder, "Don't all jobs require skills?" Although the industry name sounds vague, it does point out the unique position of these workers because their skills are tangible in a way that many others aren't.
If, on the coldest morning of the year, your heater stops working, you have to call a HVAC maintenance worker to find out what's wrong. You can't Skype him in or chat with him online. The only way for you to stop seeing your own breath in the cold air of your living room is to have someone come out and work on your heating unit.