"Direct vent" water heaters
Hello, I have lurked on GardenWeb for ages and have been incredibly grateful for all the great information. I would love some specific advice about my search for a new water heater. I'm doing some remodeling in which I am removing a chimney. My furnace already vents through the wall, so the only issue left is how to vent the water heater. I have natural gas and all other things being equal would prefer to stick with it. My plumber is recommending the AO Smith Voltex, a heat pump/electric hybrid. I'm in favor of energy efficiency but I am (1) not happy about losing hot water in a power cut; (2) suspicious that quoted efficiencies will be much lower in winter; (3) not clear that switching from gas to electricity is really energy-efficient however good the efficiency of the heater. Unless of course I were to go tankless, and I don't think I'm ready for that. Also the Voltex is not cheap, though it's less costly than running a special vent for my existing water heater through the house once the chimney is down (and there is a rebate on it).
My house is large (4 beds/2.5 baths) but I am usually the only one in it. I am in Boston MA. I currently have a 40-gallon tank and don't have any issues with running out of hot water even when I have visitors staying (rare). My gas bill in the summer is about $17/month.
Can anyone suggest a direct vent option, and are there any issues to worry about? I've heard concerns about direct vent pilots blowing out. I've been looking at the Bradford White UDS1-40S6FRN, but can't find data on its energy efficiency.
Thanks a million!