CO2 Emissions
Gas and electricity consumption are now both priced at the kWh rate so consumers can compare unit prices. The table here shows the amounts of CO2 produced to generate 1kWh of heating. Gas, oil and LPG are more efficient than electricity because they are primary energy sources that you burn yourself: electricity is a secondary source as it is produced elsewhere. The figures are from The Carbon Trust
A gallon of petrol or diesel produces about 23.6lbs of CO2 when burnt. You can use the table here to see how your driving affects how much CO2 you produce. Your average fuel consumption will also show whether HMRC has its Vehicle Excise Duty about right for your car.