I think the problem is solved. It was a combination of sealing the hole (so, thanks beenthere!
) and operator error
The jumper was not screwed in tight. And one of the wires might have got out. Everything is now nice and tight, the hole sealed (although, upon careful examination, the hole is the hole in the wall and does not go through. There is only enough space for the wires to come out, but that could also send it some draft.)
Anyways, I'm planning to mount the thermostat a little away from the wall. The walls are always cold no matter how hot it is around it. I'm surprised its not some sort of standard. Laws of physics states land takes a while to heat and a while to cool. Its not like water. If the thermostat's sensor is on the bottom faceplate putting it on a cold wall will obviously lead it to think the temperature is different. Please correct me if my reasoning is wrong.
thanks for all your help!