Make sure to get a full home energy assessment before you start energy / efficiency related upgrades. This is because most companies will offer you their product without consideration for your long term goal - an efficient, all-electric house.

In Victoria, almost all efficiency upgrades can get subsidies IF done through a registered provider.

Beware of firms offering free upgrades however. They usually offer mediocre solutions, poor quality products and sub-standard installers in order to make it free. A great example of this is swapping halogen bulbs with LED ones, when a far better solution is to replace the whole fitting and pay a little for it. The only company I've heard good things about in Vic is HomeLab.

A Selection of the best:

• Local council energy efficiency grants - check your council's website. You might get a free energy assessment.

• LIGHTS
  Replacement of flourescent, incandescent and halogen globes with LED's. If you have bulbs, go ahead. If you have halogen downlights, swap out the entire fitting for an IC-4 rated LED downlight. These units are sealed, so there are no draughts and insulation can be placed over the top.

• SHOWER HEADS
  Replacement of shower heads with water saving ones. Note that if you have an instantaneous hot water system these can cause problems at low flow.

• SOLAR PV
  Solar systems can receive both state and federal funding. In Victoria, the current rebate is $1400 while the national subsidy is based on the system capacity and essentially pays for the panels. A good solar system will cost around $1000 per kW. You'll likely be limited to a 5kW export/ 6.66 kW panel system unless you have three phase electricity. See the Solar Homes Program

• HOT WATER
  Existing electric element hot water systems attract good rebates, as do solar hot water systems. I don't recommend solar hot water systems as they fail often and they take up roof space for solar PV. More info here

• AIR CONDITIONER
  Rebates roughly cover installation cost. Get a quote from an approved provider. In any case, excellent systems such as MHI cost 1500 - 3000 installed, so won't break the bank. If your house is well sealed and insulated, two is usually enough.