Coal-Trol T-Stat 2 to 5 Degrees Higher Than the Actual Room Temp

My t-stat (current room temp) reads between 2 & 5 degrees higher than the actual room temp. It seems when the stove starts pushing heat at night the (current room temp) reading on the t-stat will gradually go 5 degrees higher than actual temp & as the stove slows down the (current room temp) gradually drops to 2 degrees above actual temp. This is over the course of several hours. Is this normal? Thanks.

I'm not sure what you mean by current temp being higher than actual temp. Do you mean you are comparing against a different thermostat's temperature reading?

I have the CoalTrol and a Digital for the Gas Furnance mounted almost together and they are 2-3 degrees off from each other..

The highest reading is the most accurate, when an electronic device is not functioning correctly it never does more.