Hi I finished a trade school program, got hired by a specialty hvac company(goethermal and specialty refrigeration) and got an apprenticeship with my local trade union. I also found a partner this year so also probably my best year yet all things considered. Anyways if you want to diy heating and cooling you can get minisplits that you can legally put in yourself at costco. The refrigerant lines are pre charged with refrigerant and have easy to use connectors.Though only expect 10 years out of a minisplit, maybe 15 if you pay someone to come out for repairs and if it needs a serious one just replace it.