I have had my unit for 2years. I set my theromstat at 70 degrees. I am having problems with my unit not cycling during average winter temperature or very cold temperature. My unit will cut on at night around 9-10p.m and will not cycle off until the next day around 9 or 10 in the morning or when the temperature outside is warmer. I know this is not normal due to observing my neighbors units work. I have called professionals out to check my unit and they say everything is work fine but I know that's not the case due to my high electricity bill of 300.00 in a 1703 sq ft house. Also, my theromstat is in the same hallway as my garage door entrance that I use as the main entrance into the house. Can anyone give me a suggestion on what I need to do?

Is this a heat pump? If so, you need 3 things to get heat, the outside compressor must be running not just the fan, the reversing valves need to be in the heating position, and the air handler must circulate the air. If all three of those are happening, and you aren't getting enough heat to shut the unit off before long, I would call a different professional. Otherwise, post back with more details.

Yes it's a heat pump. I check out the stuff you mention and get back to you.

Thanks