Q. How often in a year do you turn your heating down a bit or off for a bit and use Human Heat instead (a nice, comfy setting for our thermostats is between 18C and 21C)?
Endpoints:
Never = 0 kg
Always - (450) / (12 months) = 37.5 kg CO2
Midpoints:
A bit - (37.5) x (1/3) = 12.5 kg CO2
A lot - (37.5) x (2/3) = 25 kg CO2