We're legally required to read your meter once every two years, but we actually try to do so twice a year. If you receive a statement, saying your bill has been calculated using estimated readings, it will also ask you to give us a reading and explain how you can do this.
If you contact us at www.npower.com, we can let you know when your billings dates are due - and when to take your meter readings. This way, we can update your account and make sure you're only paying for the energy you're using.
If you're physically unable to read your meter, again, just let us know and we'll arrange for someone to pop out and do this for you.