Every time my central heating and air conditioning system has been turning on lately there has been rattling sounds coming from one specific air vent. It is the one in my bathroom. I was wondering why this was so I decided to do some research on the internet about this. And the thing it kept pointing to was that the air vent to my central heating and air conditioning system was loose. So I decided to go and get my tools and ladder to go and check it out. Lo and behold it was in fact a loose air vent in my bathroom that was causing the loud sounds of rattling every single time my central heating and air conditioning system went on. So I went and tightened the screws with the correct screwdriver and it became nice and firm. I then went to turn on my central heating and air conditioning system again to see if the rattling was still going to be happening with the air vent in the bathroom. And now the loud noise had stopped! It was indeed the fact that the air vent to my central heating and air conditioning system was loose. It was a good thing I found this out in time. That air vent could have come crashing down and killed someone, maybe even me! Those things are very heavy. So know at least I know if I hear a rattle coming from the air vents of my central heating and air conditioning system to go up there and fix them right away!