I am one that I would consider being good at understanding and learning new things. I can usually get a new skill quickly and alter my actions to be very good at working on new things. The one thing I have never been good at though are HVAC systems. I tried to figure out how to be an HVAC technician and a for one reason or another it is too hard. There exists so much that goes into performing a job like that. I have tried to fix our HVAC system at home many a times and it never seems to work out. In fact, one time I even broke the system more and we paid additional money. I kept trying to repair it after that one incident but have never been able to comprehend HVAC systems. I believe that if I cannot figure it out then no person can. Only the professionals know the way to handle HVAC systems properly. If your brother says to you he can fix your HVAC system, chances are he is probably wrong. Never leave your HVAC system with the hands of someone who does not know what they are trying to accomplish. HVAC system equipment can be costly to mess up. I gave up on seeking to fix our HVAC system in the event the air conditioning or the heat does not work. I always got it to do its job for what feels like just one minute and then it would break again. HVAC technicians are trained to properly cover your HVAC systems to always have a happy and pleasant home. It should always stay that way or you could end up with a big mess.