It also crucially tells buyers or renters what changes they can make to improve the efficiency of the property to reduce their bills. This could include everything from adding insulation to switching to energy-saving light bulbs.
The idea behind an EPC is both to inform you of what you can do to improve the energy efficiency of your property, and hence save money, and also to show how attractive the property is from an energy perspective for potential buyers. The better the rating is, the lower the cost of running the property.