My Thermostat is Trane: TAYSTAT239A and the blue light is on more than not. Does this, blue light being on, mean that my electric bill will be more? I was told that I should find a temperature and stay there but when I am gone for the day, or here for the day those temperatures are different than when i sleep at night? What does the blue light really mean to me and my retirement money? Blue light is called AUX Heat....why would that be on during the a/c process? christie_mcdonald@yahoo.com