Well it's been quite a while now, two years to be exact that this problem has been occuring. During summers the AC has been working great, but when its winter our gas heating system has been acting up. Somedays it will work fine distributing heat to the house but on other days it will just blow cold air. First time this happened I thought that I accidently placed it on A/C rather than on heat, but no it was actually on heat but it was blowing cold air. I just mess with the thermostat turning it on & off until it starts working and throwing warm air. Also I got someone to come and look at it, they tested it, all seem okay and told me that nothing is wrong with the central air system and to call them when it does start acting up again. Well I just gave and will rather just deal with it myself and do what I've been doing for quite a while now, Turning it on and off till it starts working. Oh yeah, "It's Not The Battery, I've Changed It Already."