According to this power calculation, if the hotel has 100 rooms, The total power that can be saved is about: 1300W=1.3KW. If the electricity unit is 0.1 US dollars, and each room only needs to save 1 hour of electricity per day. After adopting the select key card light switch, the hotel will annually save electricity costs: 1.3 kilowatts × 100 rooms × 1 hour/day × 365 days × 0.1 US dollars / per kilowatt-hour = 4745 US dollars.