Also, there are government rebates available in NSW and Victoria that can potentially bring this huge number almost down to ZERO if you choose to go with an efficient hot water heat pump replacing your old demanding electric system.
Factors That Affect the Heat Pump Cost
Heat Pump Installation Cost
Replacement or a Brand New Heat Pump?
Also, if you live in New South Wales, you can get your electric hot water system replaced with a heat pump as part of the government rebate as well.