Thanks guys! I already bent over and went to Depot and paid $50 for a programmable Honeywell, so I'm good to go. The real question is whether to program it or not.

I checked it out last night. I have a 3 ton unit, 1550 sq. feet. 6 rooms of cooling. 13 or 14 SEER, I can't remember (it's a HEIL unit). The temp inside the house was 83 when I got in last night. I flipped on the A/C and it took 2 hours to cool down the house to 74. Outside temp had been ~87. It was cloudy out.

What I've done thus far is to set the t-stat to 78 during the day and 74 at 4pm. I arrive home around 5:15 so I figure thats an hour to get the house down 4 degrees.

The real question is how often the system cycles on and off during the day to maintain that 78 degree temp. Thats going to depend upon a lot of conditions -- sun, outside temperature, etc.

I need to get some more insulation in the attic before winter. House was built in '64 and has 3" of insulation