Tankless Electric Water Heaters?

[Tom D.]

I have a rental unit that is overdue for a new furnace. The old one runs on oil and heats the house and the hot water.

It seems like high oil prices are here to stay. I could replace it with a natural gas one, but I'm concerned about safety issues. (And who know can predict how long natural gas will stay cheap?)

I've heard about these new hot water heaters that are electric and tankless - the water is heated 'on-demand'. I can't find a lot of good info about them online but I'm interested in learning more.

The rental unit's heat is from hot water running through radiators, it's hydronic. So I'm wondering, has anyone used one of these tankless units for the entire heating system, not just the hot water faucets?