I have a house built in 1951 (cape cod).
The house has a Payne HVAC system (high efficiency) that was installed in 2003, by the previous owner.
I did some tests, and my temperature difference between the supply and return ducts are aprox 15 degrees. (I know this could/should be a tad better).
I have a programmable thermostat, that I have set to stay at 80 degrees when I am not home during work hours. At aprox 4:30 it drops to 76.
The unit at times, runs for a few hours constantly. The temp inside the house stays at 78 degrees for the longest time. It almost seems it has trouble getting it below 78 degrees until the sun starts going down. (been like this ever since I bought the house in late 03).
Usually I notice this when the outside temp is in the high 80s-low 90s.
Is it normal for a system to run so long? I'm just wondering if I am wasting a ton of money on electricity by it running for hours on end. I imagine it will never turn off if I had it set to say 74 or God forbid 72.
Maybe leaving the house at 80 during the day is not a good idea, since the unit has to run so long to get it back down to temp?