I am taking this service for 2 years and am saving my electric bill from the group rate. Before taking this service, I used to pay my average bill $177 per month. Last year I paid average $104. It is almost $900 saving a year. However, the service itself costs a fee of $360 (2 x 180) per year. The half yearly service fee increased from $150 to $180. The increase of the service fee is one of the negative sides of this service. I would recommend the service to others.