In the new electricity bills, electricity costs vary according to the time of day. Off-peak hours are the cheapest (midnight to 8:00 a.m. weekdays, and all day on weekends and bank holidays), the standard rate the next cheapest (8 a.m. to 10 a.m., 2 p.m. to 6 p.m. and 10 p.m. to midnight), and peak rate, the most expensive (10 a.m. to 2 p.m. and 6 p.m. to 10 p.m.).