The UK Government's national, consumer-facing campaign is called "Act on CO2". It uses the AMEE platform, and is available here.

Much of the data used in ActOnCO2 is published in DEFRA/DECC's GHG conversion factors documents.

ActOnCO2 version 2

Version 2 of ActOnCO2 added more functionality and a number of new data categories were added or amended in AMEE. An important difference in v2 is that all information entered by the user is stored in AMEE; in v1 only information relevant to the calculation of the CO2 result was stored in AMEE.

  • UK heating - the /home/heating category used in v1 is now deprecated in favour of /home/heating/uk which employs a new algorithmic approach, allowing a more flexible calculation including various renewable and insulation options and more detailed return values. In ActOnCO2 v1 the user's answers for renewables and insulation did not affect the calculation.
  • Cooking - the /home/appliances/cooking category used in ActOnCO2 v1 is now deprecated and replaced by the hob and oven subcategories. The electric induction hob has been added for v2.
  • Train, bus and taxi now allow users to specify journeys by these modes of transport (ActOnCO2 v1 only included CO2 from cars and flights).
  • Flights - an option for passenger class was added and flights can be specified between any two airports in /transport/plane/generic/airports/countries. Note that this list of airports represents all major international cities and so does not list every airport for every city. For a more complete list of airports (all with IATA codes) see /transport/plane/generic/airports/all/countries.
  • Transport metadata - is used to store information about transport that does not contribute to the CO2 result of the profile.
  • People like you - contains information obtained by averaging across over a million profiles collected in ActOnCO2 v1.
  • Actions - contains information used to generated the tips and actions in ActOnCO2 v2.


To avoid double-counting kgCO2 from bill data and kgCO2 inferred from individual items (heating, lighting and appliances), an override system is used in ActOnCO2. This only concerns heating, lighting and appliances and does not involve transport at present.

The description that follows is an overview - see Results breakdown for further details on how the results are calculated and presented to the user.

Home interim result

The home interim result is displayed as soon as the user has completed the home section, which is the first section in ActOnCO2. The home interim result might not be the same as the result for the home section in the final results section.

By the end of the home section the user has provided details of their home, the heating system and lighting, and they may have chosen to provide bill data. They will not have provided any information about their appliances at this point.

There are three possible cases:

(1) No bill information provided - for home interim result use inferred (calculated) values for heating + inferred values for lighting

(2) Non-electric heating, bill information provided - use actual bill (gas, oil, other) values for heating + inferred values for lighting

(3) Electric heating - use elec bill x (inferred elec heating CO2 + inferred lighting CO2)/(inferred elec heating CO2 + inferred lighting CO2 + 0.683 tonnes CO2 x no. people in household)

Note: point 3 takes account of the fact that the electricity bill CO2 will not necessarily equal the inferred elec heating CO2 + inferred lighting CO2 + (0.683 tonnes CO2 x no. people in household) [0.683 tCO2 is the national average per individual for electrical appliances]

In each case the value also needs to be divided by the number of people in the household if the user selects 'Individual' basis for their footprint.

Final result

The final total for the home section is calculated as follows in each case:

(1) Same as interim.

(2) use actual bill (gas, oil, other) values for heating + scaled value for lighting. The scaled value is elec bill CO2 * inferred lighting value / (inferred lighting + inferred appliances).

(3) Similar to interim calculation except that "0.683 tonnes CO2 x no. people in household" is replaced with the inferred appliances value.

See Results breakdown for further details.