I live in an 1 bedroom apartment and ever since it's been getting cold outside i've been having problems with my heater. i have a honeywell pro 2000. at first on cool setting it worked perfectly fine. when i set it to 76 it would run til 75 and then turn off and switch back on when it got to 77. now that it's colder outside i am now using the heater and when i switched it to heat (not em heat) and i set it to 73 it would get to 71 and suddenly switch to aux and just keep trying to heat up but would never get passes 71 which caused my heat to just continously run and never shut off. i has the repair man come by and he switched out the thermostat and it is kinda working correctly. it's getting up to the temperature but it just keeps running and it got up to like 76! i had to manually shut it off to stop it. now it's me just having to check it every hour just to make sure it's not overheating. for the last two days i've been using the cool again because it's been hot outside. now it seems the cool is messing up too. i set it to 77 and it would run and only would it stop at 75. and it would get back up to 78 and still not turn back on to cool! is there some sort of setting that makes it offshoot when it wants to turn on or off? fyi: the setting is always on 'hold' i don't program a schedule to my thermostat.