I think you should try it. What size is your hot water tank?
I am going to install a second hotwater tank in my mechanical room and strip it of any insulation. My plan is to use the warmth from the room to pre-heat the water overnight to about 24 degrees C.
When we have demand for hot water the water will first enter the secondary hot water (holding tank) and then feed the proper hot water tank. I think this will save me hundreds of dollars if not thousands over the next ten years.
An investment like this will take years to break even. Don't expect to see a return on your investment any time soon.