About a third of household greenhouse gas emissions come from our electricity use and heating. It may be more for those with larger homes. Insulate as much as you can and consider a whole house approach to achieve the best results. When you update your heating, the best option is likely to be a heat pump.
There is lots of good free online advice from the Centre for Sustainable Energy on making your home more energy efficient.
Futureproof offer services giving independent and impartial advice and support to help with energy saving home improvements to homeowners and builders.