Do the calculations on your carbon footprint.(www.epa.vic.gov.au greenhouse calculator, car eco meter.)
Draft-proofing is one of the easiest ways to cut your heating bills. Use draft stoppers under doors. Squeeze a tube of sealant along the gaps between your walls and window frames or skirting boards. Close curtains at night and add pelmets along the top. All this will help your house to be cooler in Summer too!