Permaculture blog

How much CO2 is your house emitting?

Published by Sam Page on 20 May 2013




As the amount of CO2 in the atmosphere passed 400ppm and the government continues to argue about the size of the carbon cap that will be in their Energy Bill, participants of the Permaculture Course have calculated how much CO2 their houses had emitted over the past year.  

We used the total number of kilowatt hours (kWh) that was on our energy bills to work out how much CO2 had been released into the atmosphere as a result of heating, also lighting and powering gadgets. The amount varied widely according to how well our homes were insulated and what fuel we had used, for example:

1 kWh of heat obtained from oil produces 0.733g of CO2

1 kWh of heat/light obtained from electricity produces 0.5g of CO2

1 kWh of heat obtained from gas produces 0.5g of CO2

1 kWh of heat obtained from wood produces 0.05g of CO2 

This means that 10,000 kWh of oil emits (10,000 x 0.73) = 7.3 tonnes of CO2;

10,000 kWh of gas or electricity emits (10,000 x 0.5) = 5 tonnes of CO2;

10,000 kWh of wood emits (10,000 x 0.05) = 0.5 tonnes of CO2


           Power sources, CO2 emissions and heat loss


Electricity that is generated from power stations currently utilises gas, nuclear or wind energy. Coal-fired power stations are being phased out and gas and biomass fired power stations are being phased in....


How much CO2 did my house emit last year?
Name House type Rooms Loft cm Wall Fuel type Temp *C kWh/yr CO2/yr Solar Energy
Sam Semi-det 10 10-30 Cavity Elec 16/20 13,459 6.7t 1,000 kWh
Michelle Flat 5 10-30 Solid Gas+elec amb/21 17,600 8.8t -
Debs Mid-terrace 6 10 Solid Gas+elec amb/20 13,598 6.8t -
Max Detached 8 10 ? Oil amb/20 20,000 14.6t -
Sue Semi-det 9 10-20 Cavity Gas+elec 20-22 14,000 7.0t -
Tim&Lyn Detached 18 15 Solid Oil amb/20 40,000 29.2t -
Nick Detached 14 30 Cavity










We all have double glazing and loft insulation, though it varied in thickness between 10 and the recommended 30cm. All the cavity walls had been insulated, but not the older houses that have solid walls.  Those of us who were using gas or electricity to heat our homes were emitting less than 9 tonnes of CO2 per year, while homes that were heated by oil were emitting much more CO2 for the same amount of heat. Nick's house has only been emitting a total of 2.2 tonnes of CO2 per year because his house is well insulated and he has a wood pellet boiler and an air-to-air heat pump.

Sam's solar panels produce an average of 1,000 kWh per year to heat the water (a saving of 0.5 tonnes of CO2) while Nick's solar PV panels generate 3,650 kWh of electricity per year (a saving of 1.8 tonnes of CO2) - for which he earns money from the 'Feed-In Tariff.

While it is clear that most of us could increase the thickness of our loft insulation at low cost, the cost of insulating solid exterior walls could be in excess of £10,000. This could save up to 2 tonnes of CO2 per year. However, the only way to make the big reductions in CO2 emissions that are required to prevent extreme climate change, is to drastically reduce demand and switch from fossil fuels, such as oil and gas, to renewable sources such as solar PV, wind and sustainable wood.