Currently 17.8C here in my living room. It can drop to below 10C in here with no heating on in the depths of winter. I've insulated the best I can (loft and cavity wall) but it has a suspended wooden floor and my carpet has no underlay so I think it's losing heat through that. In the summer, even on the hottest days, it rarely reaches more than 23C, and it's south facing. It used to easily hit 30C until I replaced my big window with energy efficiency patio doors.