[Closed] Central heating ........

Heating the space when you need the heat is more efficient I believe.

I'm in the basement flat of a big Victorian house and it's def warmer if I've kept the thermostat on 16 degrees when I'm out and then stick it up to 20 when I come home. Leaving the place cold means it never gets fully warm even after a couple of hours at 20 degrees.
Depends on the volume of air you need to heat and how well insulated the house is, I guess

Brooess final sentence has it.
Uber insulated and airtight= on constantly.
For everyone else, turn it on and off.