Gas Hot Water If I Install A Solar Hot Water System Will My Gas Bill Be Significantly Reduced?

If I install a Solar hot water system will my gas bill be significantly reduced? - gas hot water

For now I use a gas hot water and I think to replace it with a solar hot water. My question is, I will save a lot of money for my gas bill? It takes a little longer to change and want to know whether it makes sense in the long run. If someone with the solar energy that are interested, know how much your gas bill, has changed, and was also the state of Australia is also, I'm in Victoria.
Thank you for all these answers in advance.