Help with energy monitoring

I have a spare aeon hem1 and was wondering if it could be used to monitor electric water heater cost. It would be nice to use it for a graph to see what it cost me with the 3 different power company rates in 24 hours. Then I could install a timer to only run on off peak times to monitor savings. I would like to use the aeon labs energy meter I have but if not is there a different product others have used to accomplish this?