I'd suspect the issue is more likely that the thermostat is somewhere that doesn't reflect the house temperature. My thermostat (which is within o.2 degrees of multiple thermometers including a thermopen) is in the hall where there are no radiators so it being set to 17 doesn't really mean much for room temperatures.
I'd suspect the issue is more likely that the thermostat is somewhere that doesn't reflect the house temperature. My thermostat (which is within o.2 degrees of multiple thermometers including a thermopen) is in the hall where there are no radiators so it being set to 17 doesn't really mean much for room temperatures.