First, I would like to say that electricity in Canada is not dirt cheap. Years ago it was, but we have had corporate thieves in charge and they have stolen our power company's blind! now, we have to make up the loss's!
I have just finished an older home reno. and had considered tankless water heating. I found that the temperature rise is hardly adequate for safe dish washer use! And this was for a gas fired unit! ( a Bosch unit ) Here in the north our water in the winter comes in at 40F temperatures and the output of tankless would be around the 120F mark. Not considered enough for a dish washer!
I have installed both high efficiency furnace and hotwater heater. These have allowed me to tear down the chimney, freeing up space on the main floor for a refrigerator.
I would definitely urge you to think long and hard about going tankless. And if you properly research these, I think that you will change your mind! These have few, if any redeeming qualities!
I would think that converting your 100 amp panel to a subpanel would allow some savings in the long run!
If you've nothing worthwhile to contribute perhaps consider not contributing.
Perhaps Gigs said what he said on the insulation with a bit of sarcasm but it was still a valid idea. I know nothing about the subject but I have been following the thread. It appears quite clearly that you have made up your mind on getting the tankless water heater. Perhaps it is because that is what everyone is using in your "snooty" neighborhood. Why even ask if every single answer is going to be "shot" down? Do your own research, read other peoples opinions, thank everyone for their help, and finally make your own decision. Nice and Simple