I am a guy who notices when things change. I am able to genuinely see when something is not right. I have never been wrong either. I periodically consider it one of my absolutely special gifts, then other people might not notice it but I sure do, and paying close attention to daily details is my task. It even came in handy the one time when my heater was acting up. I notice that everytime when my heater is starting up it makes a certain noise, and while doing some work I noticed that it had not been making the regular noise it had been all of these years. I had never had a concern with it until now. I have heard the heater start up multiple times before. To make sure that I was correct I did call the local Heating as well as A/C corporation near to me. If something was wrong it needed to be fixed. The Heating as well as A/C professional had come right over. He could tell me that the heater was trying to start up however it was not able to fully supply all of the heat it normally had before. The heating coils were having a taxing time heating up because there was a bunch of dirt plus dust covering it. The system could sense this plus the heating coil would shut off as it knew it could no longer absolutely heat the air well. The Heating as well as A/C professional basically cleaned the heating coil plus the heater was not struggling with the heat any longer. I was able to hear the same noises I had always heard in past years.