My wife and I purchased our townhouse in 2018. The house was built in 2006 and already had basic ceiling insulation and a rainwater tank, hooked up to toilet flushes.
Since then we made a number of sustainable upgrades in an effort to reduce our impact on the climate, including making the home all-electric. We worked on draught proofing, sealing skirtings and window frames and also adding DraftStoppa casings over bathroom exhaust fans. We also installed a 3.79kW solar panel system, a Daikin US7 AC system and replaced our gas hot water heater with a Sanden Eco-plus heat pump. Our stovetop was already electric, and with the new AC and hot water heat pump we were able to completely switch off gas!
These upgrades are saving us ~$2,000 per year.
Our house also features many indoor plants and an outdoors veggie patch with drip irrigation. We strive to be as waste-free as possible, buying most of our groceries from bulk whole food shops with our own containers and composting all our food and paper waste.