As I have put in my house details, my house has come to a G. Energy consumption per year came out to be 477.73 KWHRS per year and cO2 emissions are 115.48 kgCo2/year.

Reasons For Low Ratings 

Air Leaks and Draughts: gaps which are around doors and windows and the floor could let cold air into the household and let warm air escape.

No Renewable Energy Sources: One thing that keeps ratings low is renewable energy. This could include solar panels, heat pumps etc. Since my rating was a G rating my household relies on coal and oil.

Large Inefficient space: Large spaces with outdated insulation or no insulation means that there is a need for more warm air which needs much more energy and puts the rating down more.

What does a G rating mean: More carbons emissions are used which means that it brings down the rating. This then leads to higher energy bills which cost more in the end. There is also a disadvantage in comfort. A lower rating house can be more uncomfortable. It can lead to it being too cold in winter and them being too hot in the summertime.

My BER Poster