If you fit the Government’s assistance package envelope I think there are some specific areas you should look at, in order:
Whatever you build, make it efficient!, and
Whatever you build, make it efficient!, or
Whatever you build, make it efficient!
Let’s look at the math a little further out than the cost of finishing your renovation. The operating cost of your home, pre and post renovation, is very important. Make decisions on design/fixtures/appliances that include the ongoing operating costs, not just the lowest purchase price.
Efficiency needs can come from almost any aspect of your renovation – better insulation, better quality windows and glass, better quality wall insulation, LED lighting, zoned heating and cooling needs, roof cavity fan, etc. The list could go on – and that’s just the efficiency list – start with good design principles and you will be even further in front.
Once you have examined and decided on your efficiency needs you can look at automating for BETTER control (e.g. minimising active energy use – electricity/water/gas) to make it even more efficient.
If you have read this far and not fallen asleep with all the efficiency blurbs you should be congratulated.