I had a similar experience when I switched from a gas-fired tank-type unit to an electric HWOD unit. My electric bill went up less than $10/month (it was just me in the house), and it allowed me to disconnect from the natural gas company, which enforced a $39/month minimum charge even if I didn't use a single cubic foot of their precious natural gas. Net savings for me=at least $29/month positive cash flow just for switching from gas to electrical, and probably more if you could compute the savings that having an HWOD unit provides over the tanked hot water heaters.
I just spoke to my electricity provider today, they are going to now offer me an "all electric rate" and that will save me about 30% after an initial usage of 750 kwh/mo of electricity. My total electrical usage for the month of June 24 to July 26 was only 349 kwh, so some months that "all electric" rate won't help, but during the winter months when I am heating the house electrically, I suspect I'll recognize some additional savings.
Now, could I have afforded a gas-fired HWOD unit, that would probably have been the least expensive option. For now, though, considering I spend only about 6 months per year in the home, I figure I'm recouping at least $350/year just by ditching the gas bill
So, Skipjack, my only question to you would be have you considered the value offered by a gas-fired HWOD unit? You have the infrastructure, all you would need is a plumber to install one.......it might just do exactly what you want.....