A normal living room will have 3KW supply, whether that is one 3KW heater or 2 1.5KW heaters
an average heater is left on for 8 hours per day so:
3(kw) x 8 (hours) x 0.14 (night rate) =£3.36 per day
The answers ranged from 2-6 hours daily, so for the purpose of the projection we will use 4hours daily as that splits 2-6 hours fairly.
a normal living room would require a 2KW smart heater so:
2(kw)x4(hours)x0.17(normal electricity rate) =£1.36
This equates to daily savings of £2 just from one room or £730 annually assuming you use your heating every day.