I sometimes wonder if a bunch of HVAC professionals are going to come after me, but nothing like that has happened.
I actually ended up writing a book about DIY HVAC system maintenance.
I tell people that anybody who can change a lightbulb can work on their HVAC system without too much hassle. Of course, I advise that people go with the professionals for major issues like refrigerant leaks, system part replacements, and things like that, but the other stuff is a breeze. The main thing you need to know when maintaining your HVAC is to replace the air filter regularly. A vast majority of system repair calls are because of a bad air filter that the homeowner failed to have replaced or cleaned. I personally like to use pleated air filters with a good MERV rating, but HEPA filters aren’t so bad either. If you do ever plan on using HEPA filters, be sure you check to see that your HVAC system is powerful enough to handle these air filters. They have such a dense weave, and it’s no wonder, they pull 99.9% of contaminants from the air. Still, if you have a system with a weaker system fan, you might end up causing your HVAC to overheat or the system fan to break down. If you do have a powerful HVAC system though, go for the HEPA air filters if you can afford them! They will improve your health substantially, so it’s a good investment. I talk about all kinds of stuff like this in my book, so I encourage you to check it out if you want to know some excellent maintenance tips and even energy saving tips.