Your CO2 Footprint - FAQs

General

How can I find out what my own personal Carbon/CO2 Footprint is?

The Act on CO2 Calculator is the first step in helping you understand your relationship with carbon dioxide (CO2).It will provide you with an estimate of how much CO2 you emit annually from your direct emissions through the use of gas, electricity and transport fuels. The calculator will also highlight which areas of your lifestyle have the greatest effect on climate change and will provide you with advice on what steps you can take to reduce your carbon impact.

What contribution can the public make to help reduce the threat of climate change?

The public has an important role to play in tackling climate change, currently just over 40% of the UK's CO2 emissions comes directly from the actions we as individuals undertake. Reducing our carbon footprint is an easy way to take responsibility for the greenhouse gas emissions we create every time we heat our homes, drive our cars, fly away on holiday, charge our mobile phones or turn on our computers.

We all need to take responsibility for our personal CO2 emissions and make continued efforts to reduce them wherever possible. Reducing wasted energy (e.g. switching off appliances when you are not using them), being more energy efficient (e.g. using energy efficient appliances and light bulbs), are practical and affordable ways in which you can help tackle climate change.

Why do some people use the term Carbon and others use the term CO2?

The terms "Carbon emissions" and "Carbon Footprint" are very commonly heard nowadays, but the correct scientific term for what we are talking about is Carbon Dioxide or CO2, which is a gaseous compound of carbon and oxygen. Hence Carbon Footprint / Emissions is a shorthand way of talking about CO2 Footprint / Emissions.

What is a Carbon / CO2 Calculator?

A Carbon / CO2 calculator allows you as an individual, or your whole household, to calculate the amount of carbon dioxide emitted as a result of your daily actions (E.g. heating your home or driving your car). It's a useful tool to help you realise that your lifestyle and behaviour have a direct link to, and an impact on, climate change. But don't worry, the Act on CO2 calculator also gives you advice on how you can reduce your emissions.

Who is producing the Act on CO2 Calculator?

Defra is working in partnership with a number of parties, including the Energy Saving Trust, the consumer facing advice and information service for sustainable energy, to produce the calculator. We're also working closely with other government departments to ensure that the underlying data and factors are agreed across Government.

There are lots of "carbon calculators". Why is the Government producing another one?

It's true; there are a lot of calculators out there. But the problem is that the majority of them seem to only focus on a few key areas of your lifestyle, just flying for example, so you don't always get a truly accurate answer. We felt that there was a role for a calculator that used data and factors that have been recognised and verified across government departments. We are making the underlying "calculating engine" available to other parties as "open source" software, so that they can use it to power their own calculators and help to make their results more consistent across the range of calculators available.

Why should I use the Act on CO2 Calculator?

The Act on CO2 Calculator has the following key attributes:

• The data and calculations have been recognised and verified by government
• You can use the calculator to calculate an individual or household footprint
• Three areas of your lifestyle that have the largest impact are brought together in one calculator
• It provides advice more tailored to your needs, and based on your answers, rather than the overly generic tips found elsewhere
• It provides recommendations on reducing and avoiding energy waste, rather than simply offsetting your emissions

Will it be relevant to my particular lifestyle?

When we created our calculator we wanted it to be flexible enough to be able to take into account the different ways in which people live. We hope that it will be able to give tailored recommendations to you and your household, and suggest simple actions that you and your family can take which relate to your particular circumstances.

However, we have had to make certain decisions on particular aspects of the calculator. To simplify the user journey we have not included every possible type of dwelling and heating system (e.g. houseboats, mobile homes, Aga range cookers). We will continue to monitor the feedback on the calculator to establish the demand for inclusion of other minority lifestyle options in future versions.

What areas of my life will you cover?

We all consume energy produced from carbon-rich fossil fuels to heat and light our homes and run our electrical appliances, and we use petrol and diesel made from fossil fuels to run our cars. The calculator will take these direct CO2 emission sources into account.

However, we also contribute to carbon dioxide emissions through "embedded" energy that has been used to produce and transport consumer products and food. These indirect emissions are also important, but as an individual you have a stronger influence over the emissions that you cause directly, so the Act on CO2 Calculator will only concentrate on direct emissions in this first phase.

Please note: The calculator will not provide data on emissions of other greenhouse gases, but will indicate that certain actions, in particular, air travel, do have wider impacts on the climate beyond those from carbon dioxide emissions.

How can I undertake a similar carbon footprint calculation for my business?

The Carbon Trust has developed a similar calculator tool for businesses, it can be found at the following website:

Carbon Trust carbon footprint calculator

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Basis of calculation

What information will I need to enter? Will I need my energy and fuel bills handy?

To use the calculator you will need to provide some basic data that includes: the type of home you live in; its main heating system; what types of appliances and gadgets you own; how you use them; what type of car/motorbike you own; and how many flights you take per year.

You don't need to have your fuel bills to hand to use our calculator, but if you did it would make your final Footprint calculation more accurate.

How accurate will the calculator be?

If you have home energy bills and car mileage to hand, then it will be possible for the calculator to give you a pretty accurate profile. But we also want you to be able to use the calculator using the information you hold in your head. Naturally the result will be more impressionistic and based on averages. The tool is certainly not designed to give you an official reading of the energy rating of your home (this can only be done by a qualified assessor); rather it's an educational tool to help increase your understanding of climate change and your impact on it.

Will the calculator give me a result in carbon, carbon dioxide or pounds sterling?

The calculator will give you your annual results in tonnes of carbon dioxide. You can also compare your footprint with a national average and view it in different ways including as the number of footballs covering football pitches.

How will you check that the calculations are correct?

We plan to be as transparent as possible about the assumptions underlying the calculator and are making the calculating engine "open source" for others to analyse and use. In developing the model we have been drawing on the knowledge of a range of experts and government departments, but we acknowledge that this will be an evolving area which we will be revisiting and revising regularly.

What is the National Average footprint? And how did you calculate it?

We have also given you the option of seeing how you compare to the National Average CO2 emissions for Individuals or Households. The National Average is calculated by dividing the total UK CO2 emissions for the domestic sector (home and transport including flights), by the number of homes in the UK (circa 26 million). We can then work out the Individual's CO2 emission National Average by dividing the National Average for Households by 2.28 (which is the average occupancy of a UK home in 2006). If you have chosen to calculate an Individual footprint, your comparison will be against the Individual National Average. Alternatively, if you have calculated your whole household's footprint, your comparator will be against the Household National Average.

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Results

Why are my emissions higher than the National Average when I consider myself to be quite "green" in lifestyle?

There are a number of areas of your life that could be significantly contributing to your footprint. Home heating and transport choices can individually make the biggest impact on your footprint. If your family lives in a large or very old house you are more likely to use more energy for heating than an equivalent family in a modern or smaller house. Or, if you have electric heating, rather than gas central heating, your Home section will probably be higher than the National Average as gas heating is more carbon efficient than electric heating systems. Similarly, if you make long-haul or frequent short-haul flights then this will have a significant impact on your overall result.

What are the splits in the sections I can see when hovering over the graph?

We have provided information splits into the different impact areas to help you identify the areas where you have the most potential to make savings, these are Home (including heating and lighting), your Appliances and your Transport. Some areas you will have more control over than others – you are best placed to decide in which areas of your life you are willing or able to make changes to reduce your impact. We also show the splits of C02 emissions within the 3 main areas too. This allows you to focus on your particularly high impact areas more specifically.

Why does my neighbour have a significantly lower footprint then me, even though we live in similar houses and have similar lifestyles?

This could be due to a number of different factors – you will need to compare individual components of your footprint to identify the reasons for the differences. Individual behaviour in heating the home and avoiding waste of heat, hot water or electricity can have a significant impact when added up, as can your choice of appliances and gadgets such as large plasma TV sets and large American style fridges. Individual travel behaviour can also have a significant impact on your overall footprint; one long haul return flight can add a tonne to your carbon footprint.

Why are a number of impacts not currently covered in the CO2 calculator? How will the calculator improve in future versions?

In designing and building the calculator we have focused on the areas of personal action that made the most significant impact on direct emissions. We have also tried to design a tool that is relatively simple and quick to complete and not overly complex/onerous. In getting this balance of accuracy and completeness vs. simplicity and speed we have had to exclude certain impacts.

We have also worked hard to ensure our calculation methodology is based on high quality data agreed across government. Some areas were therefore excluded because data of high confidence was unavailable, or a suitably robust methodology was yet to be developed for calculating emissions from simple user inputs.

However, it is envisaged that in future versions both the coverage of impacts and the overall accuracy of footprint calculation will be further improved. Some of the areas we are considering for a future versions include:

• More detailed/accurate calculation of CO2 emissions from flights, via information on flight origin – destination flight distances.
• Expanding the named list of household electrical equipment in the calculations.
• Inclusion of an estimate of emissions from the use of public transport from frequent journey information.
• Indirect emissions, such as savings from waste recycling.
• The possibility of allocating the relative CO2 impacts from flying according to cabin class (first, business, economy plus and economy).
• Carbon savings from individual actions.
• Tracking your footprint over time.

How can I make suggestions for improvements to the calculator?

Please feel free to make suggestions for consideration via the tab on the FAQ web site. However, please note that we will not be able to acknowledge receipt, and cannot promise that all suggestions will be able to be taken up.

I've calculated my carbon footprint, and now want to go back and re-calculate as I have made changes to my lifestyle, how do I do this?

The current new live version of the calculator has functionality to allow people who have already completed a footprint calculation, and have signed up their email address and password, to go back into the calculator. Once there they can retrieve their earlier answers and update any of them with more recent data. This will then give you a new, updated carbon footprint and action plan, and also allow you to compare your old and new footprints.

What is meant by the UK CO2 emission factor for electricity?

The CO2 emission factor for UK electricity supply is basically the "carbon intensity" of a unit of energy. So for example, a unit of energy created totally from fossil fuel will have a much higher carbon emission factor than a unit of energy made from a mixture of fossil fuels, nuclear and renewable energy. In the UK the make-up of our energy generating mix changes frequently, but is calculated yearly to give an answer for the average CO2 emission factor for the year. The carbon factor we are using has been calculated using the most recent complete datasets available for major power producers (currently for the year 2005) supplying electricity to the national grid. These were sourced from the DTI's Digest of UK Energy Statistics (DUKES) for total kWh electricity supplied and from the UK Greenhouse Gas Inventory (GHGI) for the corresponding total number of tonnes CO2 emitted.

Why do you still give me a CO2 total for my electricity supply when I am on a "Green Tariff"?

The renewable electricity generation supply in the UK is currently around 4%. This clean generating capacity has already been added to the mixture of energy generating technologies that make up the UK's CO2 emission factor (see FAQ: What is meant by the UK CO2 emission factor for energy?). Hence the low carbon factor of the green energy you are using has already been accounted for and helped to slightly lower the general CO2 intensity of our electricity supply.

The important factor in opting for a "Green Tariff" is to show the energy suppliers that there is a demand for renewable energy and so they should be investing in new generating capacity, your support is vital in helping to support the expansion of this clean, low carbon energy supply.

Why is my footprint different depending on the way I have entered my bill information (i.e. cost of energy bills in monthly, quarterly or yearly format)?

If you enter cost information, the calculator uses an average cost per kWh for each fuel to work back to kWh of fuel used for the calculation. If you enter information on a quarterly basis, the calculator uses average factors for the differences between each seasonal bill to work out an annual total. If you enter your monthly direct debit figures, the calculator assumes this was constant during the year and multiplies them by 12 to get annual cost. If any of these assumptions differ from your circumstances, the annual kWh figure fed into the calculation may differ from the actual. If you can find the actual annual total kWh figure for each fuel/energy source, this will give the most accurate calculated carbon footprint.

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My Home: Heating, Hot Water and Lighting

Why is my initial intermediate CO2 result for the first intermediate Home section different from the final section breakdown result?

The initial, intermediate Home result is an approximation based on more generic national average electricity usage (for lighting your home and for heating too if you have an electric heating system), as we have not yet gathered your Appliance usage information. Your final result is based on your specific lifestyle answers and therefore is the more accurate calculation of your Carbon Footprint.

I have electric heating in my home – why does this give me a high CO2 value for my home section?

Electric based heating systems are not as efficient, in CO2 terms, as gas central heating systems. As gas is a relatively clean form of fossil fuel and you are burning it in a "primary" source in your home, rather than electricity which is created at a generating plant and supplied to you home over the grid – a "secondary" source which incurs production and transport efficiency losses before it gets to you.

Around 3/4 of UK homes are powered by gas central heating, however under 1/10 of UK homes use electric heating as their primary heating system. Therefore the national average for home heating CO2 emissions are heavily weighted to the average emissions produced by gas systems; hence an electric heating system is very likely to be higher than the average.

There are some suggested actions that don't have related questions in the calculator. How can I see what difference these issues might make?

These are issues (such as reducing thermostats or adjusting time controls) that we have not yet been able to incorporate in the calculation. However, if you record your actual kWh from bills before and after you make these changes in your house, you will be able to see the difference it makes. Adding the new bill data into the calculator will give you the CO2 savings you have made.

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My Appliances

Why are you asking for information on my electricity use (through the Appliances questions) when I have already given you my electricity bill information? Are you not double counting?

No, don't worry, we are not double counting.

If you do not have your bill data handy, we do then use the answers to the questions in the Appliances section to help us estimate what your electricity consumption is, which we then turn into your carbon footprint from electricity and add to your total.

What is included in the "Other" sub-total of the appliances section? Why is there a high proportion of my appliance CO2 emissions allocated to "Other".

We have covered the most common/major electricity using appliances in the home in our calculator. Nationally it is estimated that (excluding electricity for heating, lighting and hot water) the remaining electrical appliances account for around 5% of the other domestic electricity use.

The "Other" sub-total is therefore a measure of the electricity it is not possible to specifically account for in the calculations based on inputs to the CO2 calculator. If you regularly use a significant number of other electrical appliances, or any high energy consuming equipment then this will be accounted for in the "Other" sub-category. Individual pieces of electrical equipment may also use more or less than the averages assumed in our calculations, which may also account for the difference. The "Other" sub-total may also account for a significant portion of your appliances total if you have provided the electric bill information, but incorrect information on some of your answers.

I have an Aga range for cooking and hot water generation. Why do you not include this type of system in the calculator?

We have had to try to minimise the number of appliances and other systems in this first version of the calculator. Subsequent versions of the calculator will take on board feedback from users on which popular appliances we should include in subsequent versions.

However, generally we can say that Aga systems are very energy intensive. For example, a typical oil or gas-fired unit can use around 20,000kWh of energy each year; this is enough energy to meet the total annual space and water heating requirements for an average semi-detached house. While a range cooker can provide hot water and can offset the energy used by some other appliances, they remain significant energy consuming appliances.

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My Transport

How does aviation contribute to climate change?

The full climate impact of aviation goes beyond the effects of CO2 emissions. Apart from emitting CO2, aircraft contribute to climate change through the emission of nitrogen oxides (NOx). This forms the greenhouse gas ozone, especially so when emitted at cruise altitudes. Aircraft also trigger the formation of condensation trails, or contrails, and are suspected of enhancing the formation of cirrus clouds, both of which add to the overall global climate change warming effect. These extra impacts are examples of effects which are collectively known as "radiative forcing".

There is still considerable scientific uncertainty about the scale of the impact of these radiative forcing effects. However, the climate impact of aviation emissions, including radiative forcing, has been estimated by the Intergovernmental Panel on Climate Change (IPCC) to between 2-4 times that of the direct CO2 emissions alone. Currently, government uses a factor of 2 when offsetting its business flight travel.

Is there a difference in the relative CO2 impacts of different cabin classes for flights? Why are they not currently taken into account in the current calculations?

The calculator is based on average emissions from an illustrative aircraft type used on domestic, long haul and short haul routes. Broad assumptions are therefore made on the type of aircraft used for particular route lengths and the associated typical load factor. We acknowledge that as business class passengers take up a greater proportion of the floor area than an economy class passenger, the CO2 emissions attributable to that class of passengers would be higher and likewise lower for economy travel. However, for the purposes of this tool, we have simply represented emissions on an average basis and consider that disaggregating the analysis into different classes of travel might infer a degree of accuracy in the model that was misleading given the broad assumptions outlined above.

The overall objective of the calculator is to provide a guide for individuals to help inform their decisions and lifestyle choices. It is intended that the tool will be under development but as this is an early version, it is subject to many limitations across the whole range of activities which we fully recognise. However, we believe that the development of this calculator is a substantial step forward and we will endeavour to improve it as more evidence becomes available.

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Action Plan

Can you give me more information about how to implement my action plan?

Clicking on the "greener living" button on the results page will give you a wide range of further information.

Why does the action plan recommend things that I'm not allowed or able to do in my type of home?

It may be that you live in accommodation where there are restrictions due to a lease or rental agreement or because you might live in a conservation area. The action plan recommendations cover a wide range of situations and do not, at the moment, differentiate between these circumstances. If the recommendations involve parts of your home for which you need to get permission (eg wall insulation) why not discuss them with your landlord or freeholder? You would gain the benefit of improved carbon footprint and lower energy cost, while they would get an enhanced asset.

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Technical

I can't see all of the navigation buttons at the edge of the screen. What do I have to change to see them all?

Your screen resolution needs to be increased beyond 800x600 pixels. This can be changed via control panel/display/settings; the ideal is 1280x1024 or better to see the whole image. However, staying at the 800x600 resolution will not affect the working of the calculator.

Why do you ask me to register? I don't want to be bombarded with promotional e-mails.

Registering at the beginning will mean that you can come back to the calculator at a later date if you have new information. We will only send you information e-mails (not promotional material) if you tick the box on the registration pop-up. Since we do not have your full address, you may be assured that there is no link to any supervisory or other database.

I would like to see more detail of how the Calculator was designed. Where can I find this information?

You can view the methodology paper, that sets out how we have gone about developing the Calculator Defra's website. View the methodology paper

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