To give you an idea, we installed the SmartEnergy unit in two different residences and compared the electricity bills from one month to the next.
First trial: a two-person flat (a couple) of 592 sqft (55m²):
Average bill over last 12 months (before installation): £122
Average bill after 3 months' use: £21 (82% reduction)
Average annual savings: £1,200
Second trial: a five-person house (two parents and three children) of 1560 sqft (145m²):
Average bill over last 12 months (before installation): £355
Average bill after 3 months' use: £42 (91% reduction)
Average annual savings: £3,566