I do not want to pay for any heating, so the whole oil burner/radiator heating system I do not want to use at all. Never. Ever. About 500 dollars a month so far this fall and winter.

However I really want hot water!

How hard or expensive would it be to just install an on-demand electric heater for the kitchen sink downstairs and the shower upstairs? At a minimum this is all I would want to pay for.

I'm guessing because the radiator water pipes recycle water to generate heat, it would be harder to install a tankless electric water heater. However, I have no interest in cross fitting the two systems, I would smile and rip out these radiator heating pipes in a heart beat if it made installing a tankless heater easier. Could I have two small tankless water heaters, one for the kitchen/bathroom, and just run new water pipes?

What's the easiest/cheapest way to get hot water to a kitchen sink and shower, that's all I want.