My T-stat had lo on the screen so I changed the batteries. At the same time, I changed both filters. The fan is running (I did this as a test) and it is on cool. Registers 83 degrees when I set it to 60 degrees. Why is this? I had no problems before I changed the batteries.

Thanks.

Is the outdoor unit of the A/C running? Most thermostats have a built in delay for the outdoor unit after a power loss (including battery change). That delay is normally 5 minutes & if the outdoor unit also has a delay that amount has to be added to the stat delay.