our best investment has always been passive solar design, excellent insulation including double glazed windows and lined curtains and although we've just installed new reverse cycle air conditioning and solar panels in our old house the research suggest that electric with a Solar battery (to be added when budget recovers) is the best option and despite our long cold winters about 40 years experience with Solar Hot Water and Power has shown that the panels produce useful power throughout the year and extra produced in summer offsets the reduction in winter and we've also saved about 3000 KG of Co2 emissions which is equal to planting about 100 trees every year

Thanks Louise, very helpful as always.
Could you please elaborate on the insulation bit.
I am yet to organise the insulation, so anything in particular I need to tell the boys (Pardon my ignorance)

With Solar, do you have to have a battery or the surplus sent to the grid in terms of credit will help offset your bills.

Sorry totally new to all this 😬

our batteries will have to wait until our costs reduce or savings increase so we have power sent to the grid for a fee and then buy power the same as everyone else but buy back prices are different in different areas so check with your local suppliers and i believe there are great variations in prices of initial systems (but looking for minimal maintenance and customer service we paid more for a Solar Hart because that's the brand we've happily used for many years in a different house) but keep in mind that the system can be retrofitted to any house and extra panels can be added later to increase production ie any savings would probably not equal extra compound interest if you have to increase your mortgage to cover costs of buying the Solar system but always best to include highest rated insulation for your house during building as never easier to install than during construction but best choice depends on location (check yourhome.gov.au for advice about solar and insulation and insulation manufacturers' websites for specifics) we have foil under steel roof, bats inside roof space above ceiling and also inside walls between rooms (for sound reduction and privacy as well as solid core doors to help zone the temperatures...ie no need to run AC in unused rooms...regardless of how long the Solar Systems take to recoup initial purchase costs we're very happy to be reducing emissions for the future and the costs savings are seen as a bonus and we save power by turning off switches, wearing jumpers inside, washing in cold water, shorter showers and using ceiling fans and ventilation...good luck with your new home

There's a move away from gas to the extent that new suburbs where I live are not even being provided with gas mains. Evap cooling when we researched some time back required some windows open and I remember people complaining about that during last summer's smoke. Regardless of which systems you choose, I could not agree more with oklouise, start with good solar passive design and insulation, that's the most efficient way of reducing the reliance on and cost of heating and cooling systems.

Thanks guys
Basically, insulate the hell outta it!

yes but check the ratings for the best insulation to suit there's a whole range of different products to suit different situations and (unless you lived in the tropics which needs a different approach) ..i've assumed your new house with concrete slab and it's also possible to insulate the slab and/or under timber floors.. good insulations means that you can keep the heat inside in winter and outside in summer and there's no ongoing costs once installed

following macyjean's comment about the move away from gas we recently added hot water heating to a new build and the air sourced electric water heater we installed rated far better for our BASIX rating than gas

Yes, it’s a new build
Slab to be poured this week or so
I spoke to an insulator & he reckons earthwool with HD & between walls too for better efficiency.
While we’re at it, anything else to include or not to include or be mindful.
One of those is wish I had done this’ monuments :)

I’ve come across Hydrotherm Heatpump water heater has great reviews
Which one were you referring to?

bit late for changing any walls but might still be able to reconsider doors and joinery if you want to post a copy of the plans showing readable dimensions and the Heat pump we chose is a Sanden that was about $5300 plus installation costs after STC rebate of about $2000 ... so far very pleased with excellent performance...but you have to save a lot of running cots to compete with installing a modest electric HWS for less than $1000

This will be familiar to you :)

i recognise plans before i remember names and your final plans look good although the wardrobes could be longer (no closer than 1m to the door wall but longer than shown on the plans) and Reverse Cycle electric AC with great insulation would be my choice for heating and cooling and make sure you don't overcapitalise with expensive HWS unless you expect to be providing hot water for more than two adults

I am glad you like it
The wardrobes are just kinda like a guide
They’ll be customised with appropriate size etc