CL (Controlled load) meterage might be something that you can consider, if it is offered by AGL in your area.
Before we went solar (and had to upgrade to a new digital meter), we had 2 analogue meters, a normal flat rate one for general power, and a CL meter for the HWS.
I believe other heavy use like underfloor heating, possibly large air cond, pool heating etc, can be hooked up to CL.
By definition of the flat rate you have, it seems you would definitely have a normal analogue meter, maybe you can contact AGL and ask if a CL meter can be added for anything suitable you might have for the CL rates.
(They might only offer upgrades to digital meters, but worth asking.)
CL tariff is reasonably less than a normal flat tariff.
Otherwise, Neil is right, you need a digital meter and go onto TOU (time of use) tariff.
But do so carefully, it is not easy trying to compared these tariff amounts, and estimate if it will work for you better than your current situation.
3 main things to consider with going digital meter and TOU tariff.
1. Be aware of the rate you pay now, and the various rates you have in the general TOU tariff, peak, shoulder, and off peak.
In SA at least, peak (2 blocks during the day) is quite a bit more than normal flat rate tariff, shoulder rate is lowest of all and during the day when there's excess solar going to the grid, and off peak is between those two.
2. Do you use power in the time blocks where you will pay less overall on shoulder and off peak ?
And do you want to monitor your usage to a point where you can save some small amounts each day (which can add up to quite a bit over 30 or 90 odd days).
3. Once you change to a digital meter, there is no going back to analogue !
And generally if you go onto TOU tariff there is no going back to single (flat) rate !
I believe you can go to digital meter and ask to stay on a single rate, but the only real benefit there is the retailer doesn't have to read the meter any longer.
If you updated to a digital meter and TOU, and decided to get CL meterage as well for any usage applicable, CL tariffs are somewhat less than normal TOU rates, and apply during the same 3 levels of TOU tariffs.
Check your offerings on the AGL or Energy Made Easy websites for YOUR local rates for single and TOU etc, they vary a heck of a lot across the nation.
Good luck.
