A modern, direct-vented, condensing hot-water heater will have an annual fuel utilization efficiency (AFUE) rating  >90.   

Or, since this is a hot market and we are planning on living in this house we have nothing to lose by asking for a little more? 

@Jessie BienvenuYep, @Ben Leybovich hit the nail on the head...you're jumping into an arena that can get you into more hot water than you can ever imagine.

I fully agree with Michael McGee: Sell your interest in the property as fast as possible to your new partner who paid the back taxes and redeemed the property - unless so much lot of value in the property and profit to be made by staying in the deal and putting up with the many problems of finding and negotiating with all of the other 13 heirs to buy their interests out at bargain prices that is a really smoking hot deal! 

@Rory Gill Welcome.You're looking in some hot areas but working there is a help!

If it's in a hot neighborhood in NY or CA with Chinese investment pouring in as they flee their home economy, a 6% cap rate ($2.7M!) 

Due to all this I decide to put Real estate investing in hold I also run my own hot shot trucking rig that I've put on hold until I'm done with all this!

In addition to looking in Manhattan, I suggest you also look in the Bronx as it is still less expensive but hot and increasing in interest. 

Looks like crap after a while, if you get a hard rain and have any drains nearby, it can cause quite the clog and like @Pat L. mentioned above, smells like a tire factory on a hot day.

Hot tubs  are a hot ticket item in the Smokies :)