I live in Indiana first year in a newer house ( Built in 95) it is a 1100 sq ft ranch. A/C did great in the summer time. Unit ran about 12 min each cycle. Now we are in the heating and it is running about 35-40 min. Sometimes longeer. Right now it is about 25° outside. Inside set point is 68°. If this normal?
Those run times are fine, acutally good. Many times heat pumps will run continuously at those outside temps.
The run time will be a function of the heat pump sizing and efficiency as well as the house's heat loss. At some outside temp the heat loss of the house will equal the heat capacity of the heat pump (for that temp). This is called the balance point. The heat pump will then run 100% of the time at that temp, which is fine. Below the balance point the auxiliary heat (most likely electric strip heat) will come on occasionally to provide some additional heat for the house.
So don't be concerned. Sounds like you have a good, economical system.
Yes, I have a fancoil with electric heat back-up. Thanks for the input. Hopefully the electric heat will stay off and keep the electric bill down!