The biggest one was probably a combo of having an anemometer, and heat/humidity sensors in each room.

When it’s cold outside, the top floor of the house (loft conversion) loses more heat. But it loses significantly more heat when it’s cold, and the wind is blowing parallel to the floor joists.

I realised that because they’re not perfectly sealed (old house), enough air pressure means that the floor void can easily hit external temperatures, meaning the rooms have cold on twice as many sides.

I will (eventually) get some suitable insulation in them to stop this.