How can I calculate my carbon footprint?
It is relatively easy to measure your carbon footprint from energy used in the home because all homes have an electricity meter and most have a gas meter too. To get a feel for how much energy you use you'll need to make a note of your meter reading or readings at least every month. Then you can experiment with seeing how you can reduce your electricity consumption by turning off lights or appliances presently left on stand by. You may also be able to turn down your room thermostat and wear warmer clothes indoors to save gas.
The panel opposite, from my book, describes another situation where you can use your electricity meter to check on your consumption.
It is also easy to record, at least every month, how many miles you drive in your car.
My book explains how you can convert your meter readings and miles driven into carbon dioxide emissions. Adding all these figures together gives you a good estimate of what are called your direct emissions. These can be calculated online at www.carbon-calculator.org.uk or you can download my own calculator which uses an Excel spreadsheet or a simple 2-page form which you can print off and which may be easier to use with a desktop calculator.
Indirect emissions come from buying food, clothing, electronic goods etc., in fact from consumerism in general, and are much harder to estimate. Very roughly, our indirect emissions are about the same as our direct emissions.
"However, there is one special situation where it is worth taking electricity meter readings close together. Most homeowners would expect their overnight electricity consumption to be close to zero except for energy consumed by a fridge, freezer, fish tank or alarm system or anything else that operates 24 hours a day. So if you read the meter just before going to bed and as soon as you get up in the morning and take the difference in readings you will be able to estimate your ‘baseload’ consumption, that is what you consume continuously all year round. To estimate your annual baseload within 100 kWh you will need to make each meter reading to the nearest tenth of a kWh (the first number after the decimal point). This will be an important number because there are 8760 hours in a year! For example, if your overnight consumption is 1 kWh over eight hours then you will be consuming around 1100 kWh in a year equivalent to emitting around 0.55 tonnes of CO2! This is a neat way of detecting all those appliances that still consume electricity while they are left on stand-by or which have been forgotten while plugged in to some inaccessible wall socket. Seek them out and disconnect them, then repeat the experiment to see how low you can get your overnight consumption. In our own home we’ve managed to cut our baseload to around 300 kWh per year, excluding the fridge-freezer, which is equivalent to about 35 watts running continuously or consuming 0.28 kWh overnight."