I know that this is a very personal preference and also dependent on the house you live in, but 23°C would feel uncomfortably warm for me, even in a t-shirt. We

I know that this is a very personal preference and also dependent on the house you live in, but 23°C would feel uncomfortably warm for me, even in a t-shirt. We set the thermostat to 19°C this winter and mostly wore sweaters and were fine. Turning down the heat by 1°C saves about 13% energy, which I wouldn't say is "small": https://cambridgeenergy.org.uk/wp-content/uploads/2013/11/CAR-Behaviours-Final-Report-Revision-3-060812.pdf https://cambridgeenergy.org.uk/wp-content/uploads/2013/11/CA... In the report they actually look at a temperature reduction from 19 to 18°C, so dropping from 23 to 22°C should result in an even larger saving.