It's prohibited for one. And for two, to actually run an electric tankless will require most of the power that you currently have in your panel. 125-200 amps are needed. If you live in a cold climate, electrical is not really doable at all because of the incoming winter water temperature. Gas tankless is much easier to retrofit, and even it may require new gas service for the home.

Have to disagree with GreenDesigns who states, "they offer almost zero improvement in efficiency of a new high quality tanked electric heater. ...electrical tankless is only truly practical if designed for a new build from the beginning. Retrofitting is extremely expensive and won't give you a payback for the cost differences inside of your lifetime." I put a whole-house electric tankless in my 1906 house and will never store water in a tank again. Absolutely love it! It's mounted on the wall, directly to the side and just above the dryer. I did not bother to hide the water lines inside the wall, but since they're [mostly] hidden by the dryer, who cares? Sometimes, putting plumbing pipes in the wall is highly overrated. Mine is in the bath/laundry room and I've never found it to be unsightly. Yes, the tankless requires quite a bit of power: Mine requires two, double-pole 60amp breakers with 6g wire. So, here's where distance from the electric panel is a cost consideration.

Another take on the induction question with a little sprinkle of humor. https://www.eevblog.com/forum/chat/induction-cooking-emf-magnitude-vs-other-things-missus-is-a-bit-concerned/  Tim says, Ugh... If she's worried about cancer... dump her now? There's no convincing someone like that, to understand statistics and significance. At least that I've heard of. If you're looking for the opinion of an EE, I would gladly give you my opinion on the subject -- if you'd like it in writing, I can even sell your wife a certificate saying as much! Maybe that wouldn't help. I don't know. What are we talking about, anyway? Cooktops aren't always-on. They're either off until turned on, or pulsing infrequently to check if a pot is present. The RMS EMF at the surface is not very large either way, when not actively heating something. When heating, it's only large under the work being heated. EMF drops off rapidly with distance. If your wife is so strange that she finds it enjoyable to read books while laying over the cooktop, I might be concerned, but only for mental health reasons, not for EMF reasons. Or if shoving her head towards a pot that's being heated, I would be more concerned for safety reasons, and then mental health reasons... There are biological effects of EMF, but not at these field strengths. Not by orders of magnitude. The primary effect is simply dumb old heating. Diathermy machines, microwave ovens, and the military's ADS, operate on this mechanism. There is no biological effect beyond heating (obviously, too much heat and you cause burns, but that's not unique to EMF). Strong pulsed fields can induce voltages in neural tissue (transcranial magnetic stimulation), which do have direct neural effects, but these are temporary. Anything that produces fields with too little energy to cause noticeable heating, or pulse peaks strong enough to cause noticeable induction, is completely and utterly inconsequential. Example: ESD can have quite large (peak) EMF, but is over very quickly, and delivers very little energy (on a human scale). (Anyway, sparks are well known to cause people to involuntarily jump or twitch. But again, that's just a neural stimulation thing, nothing more.)

Waht are you asking? How too use it ? Not sure what you want from us.