Wales 

Everest study analyses 15,623,536 home Energy Performance Certificates (EPC) across the country to reveal the best and worst rated areas for energy efficiency

Despite being the most expensive place to live for property prices – London homes are the most energy efficient and paying the LEAST on bills

Tower Hamlets, Greenwich and City of London top the chart as the three most energy efficient areas in England and Wales with the MOST A- & B-rated EPCs with energy bills costing just £1,650 on average (in 3 years)

The average EPC rating for a dwelling in England and Wales is D

The study reveals the 10 WORST areas with the most F- & G-rated certificates that cost nearly 3.5 X of those in London