Hi! I am a young homeowner (about 2 years now) and when my wife and I were getting the general inspection it was noted that our AC used R-22 refrigerant and might need to be replaced if it started leaking. After hearing how much it would cost to replace a system (and having some ideas of my own for improving IAQ) I have started down the road of getting prepared for a DIY replacement should that happen in the near future. From reading a few posts it sounds like getting the universal EPA 608 is a good first step. Are there any recommendations for online training courses that teach the material well? A quick search showed SkillCat but I am curious if anyone had any preferences. Thanks!

...and replied to a couple threads, and read the rest. My first thought is that nobody around here so far seems to be in a state where they could pull off an install. There is a massive gap between somebody who knows how to build an IKAE set or drill a hole in the wall, and installing a complete HVAC system. I was expecting to find DIYers that are used to pulling an engine from their car in order to replace the cam. I'd consider those type of DIYers a good match for learning how to do HVAC. But what I'm seeing so far are folks that don't want to get ripped off, but completely lack any proper handyman skills. And I don't think that many are willing to fill in the HVAC skill and knowledge gap in this busy world, next to a full time job and family obligations. Maybe this will change over time and Dave's YT channel is the best starting point. That being said, he as been around for years. I don't think that most homeowners understand how much they have to catch up to make this work for themselves. I think new members to this forum should be informed right away, that DIY in this field requires true commitment. They won't get solution by asking questions and then not even coming back to their own thread, let alone buying the suggested tools and actually getting it started. Wonder how many bought some tools and soon gave up.