Normal
Over time, the callibration of the thermostat may have changed. It sounds like that's what has happened here.You either just put up with it, and accept on some of the heaters you need a higher setting to get a particular room temperature, or you replace the thermostat.The latter option is not always easy as to buy one new you might as well just replace the whole heater. Sometimes you can find them second hand on ebay.Would you feel competent stripping it down to change the thermostat? If not by the time you have paid an electrician to strip it, identify the part, order one, come back later to fit it, then it would probably work out cheaper to get a new heater.Personally I would choose option 1 an just accept you need to use a higher setting and carry on using them.
Over time, the callibration of the thermostat may have changed. It sounds like that's what has happened here.
You either just put up with it, and accept on some of the heaters you need a higher setting to get a particular room temperature, or you replace the thermostat.
The latter option is not always easy as to buy one new you might as well just replace the whole heater. Sometimes you can find them second hand on ebay.
Would you feel competent stripping it down to change the thermostat? If not by the time you have paid an electrician to strip it, identify the part, order one, come back later to fit it, then it would probably work out cheaper to get a new heater.
Personally I would choose option 1 an just accept you need to use a higher setting and carry on using them.
