Note: this document was written in 2008 from the viewpoint of the year 2015.
Looking back to 2007, the entire attitude towards domestic energy use has undergone changes which have been faster than the normal replacement cycle, driven by a mix of higher costs, incentives, and publicity.
One of the simplest things you can do to reduce your carbon footprint is to reduce the energy used to light your home. You may be surprised at how big an effect it can have! More
Take care not to spend any money saved in a way that inadvertently causes other emissions.