My ranch style home in the country with well water has a 40 gallon electric water heater. Even though we have a special "reduced rate" electric meter for it, it still costs north of $30 to $40 a month to run it. I'm tired of the high cost and want to switch to a gas unit... I'd go tankless but I think my well water would shorten the lifespan.

I do have a NG forced air furnace (we heat with wood so its only a back up unit).. but I don't know if I can plug into the vent stack on that.. not sure how to calculate how big the stack needs to be... Any advice on this?

So, while I would prefer to just get a run of the mill 40 gallon water heater and stack it in with the furnace stack, I'm thinking that I'm going to be required to get a power vent type.

Some local guy has a Lochnivar DVN041 for sale that he says was only used for 2 weeks for $250.. Suggestions?