It's tiny. Even though I'm largely working on a remote machine, there's enough warmth from the hardware in the room to keep it toasty.Have you done the maths on just getting an oil filled rad for your office?
It was just my wife yesterday and I suggested she knocked the heating off schedule and just used the oil filled radiator, but then second guessed myself as the fabric of the building would cool and then it'd be harder to get back up to temperature.
I am not a thermostat though so I don't know if that is totally true.
The main problem is our rabbit's favourite sleeping spot is right in study doorway, so it ends up being open half the time