We have a heat pump and replaced it 4-5 years ago when our old one died. Our home is well insulated and we keep it closed up during warm-hot weather. About a week ago it got very hot again, but not as hot as it's been earlier this year. We have cool air coming out of the vents with a normal force, Service man said freon level was good. At night time our house doesn't cool down but maybe 1-2 degrees, when the outside has cooled 20 degrees or more. The house does not cool down below 70, with thermastat at 65, and night temps 64 or less... What could cause it to run continuously and not be as cool as it was?

You have a real bad outside to inside air leak OR find a more qualified service person. If it worked last year it should work this year. Something must be wrong.

Finally after having the service man return several times ( 4-5) he discovered that a small circuit board has shorted and would not allow the air handler to shut off, therefore, supposedly kept circulating air when the compressor shuts off, and was causing the air to warm and keep circulating. I don't quite understand the whole concept but iut made sense finally. The system seems to be working fine again now, however the outside temps have dropped outside to a 70-72 F. The system is cooling again to the set inside temps, may know for sure again because the next few days are getting hot again. Thank you for taking time to help. :)