Depends on circumstance. Not home, or sleeping, about 11-13c (it is actually a range, so it heats up to 13c, then stops, and only kicks back on when it hits below 11). When I'm home, about 22c. If I'm feeling chilly I might crank it to 24c. I work shifts so I made my own custom thermostat system where I can input my work schedule. Basically there are profiles for each shift type. 12h day, 12h night and 8 hour day. Then I have 12h day weekend, which simply skips heating during lunch time.
Rarely do I get to actually feel the house at 11c unless it's night and I have to get up to pee. (and that sucks!) I'd actually put it lower but I'd need to put more sensors around the pipes to play things safe.
In summer, I leave the system on a blower only profile, and it just kicks on the blower a few times per day just to circulate the air. I don't have central AC. Eventually I'll get it but it's on the bottom of my priority list. It's a "nice to have" thing that I can get away without. I have a portable that I setup in my office so I can at least cool that room down to a comfortable level when it's hot.