Electricity bills are generally always based on estimates so do not actually give you an accurate picture of how many Kwh (kilo watt hours) of electricity you use. There are some relative cheap devices you can install both in a domestic situation or a commercial building. For households the best one I’ve come across is the Google Powermeter. The Powermeter is clipped on to the electricity supply coming into the house and feeds its results back via your broadband connection to the internet where you can login to see what your power usage is.
How am I doing?
A typical 3 bed semi with 2 adults and 1 child uses approx. 370 Kwh of electricity per month. The Powermeter shows how you compare with other users, what the costs of your electricity usage is, and what the base load is (how much electricity is always being used in your house). The Swingometer above is showing the actual energy use in my own home and is only one of the features of the Google Powermeter.
You can find more out about Google Powermeter’s from http://www.google.com/powermeter