I live a fairly newer house in the Chicago suburbs and the A/C seems to be running an awful lot to maintain the temperature in the house. Right now it is 94 degrees outside with a dew point of 56 degrees and the air conditioner has been running pretty much non-stop for the past hour. I have the thermostat set at 75 degrees and the house is comfortable, but I was just concerned at how much the unit was having to run. The unit is supposed to be a 3.5 ton carrier. I measure the temperature on the air coming out of the registers at it is 58 degrees. The house is a 2800 sq foot ranch style house. The living room, family, eating area and kitchen all have 11 to 15 foot high ceilings. The front of the house faces south and has about 45 sq feet of windows covered with both blinds and drapes that are currently closed. Does it seem normal for the unit to run like this given the conditions or should I have the unit checked to make sure it is working correctly?