Here’s a surprising analysis of energy efficiency, about space heating(also cooling) by Matthew Wright from BZE.
In Shire of Bass Coast, folks on the mainland now have natural gas. On Phillip Island, it’s deemed “too expensive” for the pipeline. Wherever we are, we’ve been bombarded, from Canberra, by publicity that “gas is clean(or cleaner)” and “more efficient”.
Compared with electric element type radiator heating, gas may well be cleaner and cheaper. But gas into your house needs to be just burnt before it makes any heat. Obviously a lot of thermal energy(up to 70%) is lost up the flue.
Compared with up to date, inverter, reverse cycle, split system air conditioner gas doesn’t compete. Electricity used to be “burnt” by old fashioned electric element heaters. But aircon heat pump principle just moves heat, between outside and inside, which means you get as much as 5 to 6 times more heat transfer, compared with “burn” of raw energy. This is based on recent technology inverter systems, with automatic controllers sensibly set to only heat up to 18degC and cool down to 24degC. You can obviously still break the bank, during heat wave, if “somebody” overrides setting for 15degC, not a cool thing to do.