I’m in the US and I never got any formal education in my trade (HVAC-R). Most of the techs here didn’t. The few techs we’ve hired who did go to trade school came out of it with practically no knowledge which couldn’t easily be taught on the job in a couple months. It seems like, for HVAC at least, the tradeschool programs teach enough that maybe you could manage some light residential work, but they barely touch on refrigeration, let alone the heavy commercial and industrial refrigeration we often do. When evaluating candidates, a tradeschool cert means less than a year of experience in some sort of maintenance position.

The same seems to be true of many other trades. At least in my state no certs are required or even beneficial to become a licensed plumber or electrician. Those liscenses are all based solely on years of experience. Technically you can become a master electrician solely with an electrical engineering degree and 0 years of experience but if you have that degree then you probably have better jobs available to you.