Two things to remember about the TINY heat pump on top of the hot water heater. It only removes heat from the room to replace the BTUs that are removed from the space via hot water going out the pipe. Example. You go on vacation for a week. ZERO net heat is removed from the room. In other words, heat transfers from the stagnate hot water back into the room and then the heater kicks in and removes it from the space and transfers it back into the water... not free, but very inexpensive and absolutely no need for the home's heating plant to make up any heat - as I said, no NET heat loss or gain. Now take the case where you take a hot shower upstairs. ANY heat removed from the basement by the hot water piping remains inside the conditioned household envelope except that which exits via the plumbing drain in the shower. Also, presumably cold replacement water from the street is brought into the envelope to replace that drained water. I have NEVER seen a change in my basement temperature due to the heat pump hot water heater because my subterranean basement is simply a massive heat sink that resists temperature change big time. While I do remove like a pint of water from the air per day in the summer, I have never been able to measure a change in humidity - just the nuisance of having to deal with disposing of the condensate. You're creating an apples and oranges situation when you compare heating with gas and "pumping heat" from the room into the water. With your gas heater, the heat that 'flows' back into the room is not recycled back into the hot water heater, rather it is "replenished" by bring NG into the room and igniting it in a non-recoverable manner. The net effect is to heat the room while you are on vacation... as I suggested there is ZERO net effect with the heat pump hot water heater in my example. I have documented in this forum that my electrical savings for my family of two is approximately $40 per month due to the hot water heater as compared to the electric hot water heater I previously owned. I also have tried, with mixed result, to explain that taking the basement as a system and drawing a diagram show heat in and heat out of that system is helpful. Too many folks that have never owned one of these and have made false assumptions have reached conclusions that are absolute nonsense. My unit is a GE model... I had a compressor leak after 11 months that was repaired under warranty. Reportedly this problem was not an isolated case... and the Model was discontinued. If you have the time, the final math problem (actually rather simple) is to assume some water usage and calculate the enthalpy rise in the heater times the gallons and determine how much heat is being removed from the basement... that is the amount of heat that your heat pump would need to replace in the basement to maintain equilibrium. If I were the OP, I suspect I would opt for the Gas heater because the response time is faster, because it is quieter, and because he will not have to mess with disposing of a pint of water every day during the summer. But, I suspect that you need to caution the OP that his heater is heating the inside of the house during cooling season. :-) I played loose with my terminology re Heat Transfer in the above in order to attempt to better communicate the concepts - by background and education I am capable of using proper terms and terminology, but choose this approach.

Gary, IMO you answered your own question. Given the fact that a BW WH provided you 15 years of service, there should be no question as to what brand you purchase. As far as efficiencies are concerned, yes, there are units (BW included) that offer high efficiencies; however the more technical they are, the more to go wrong with them. The $10 / month that you are spending on keeping a pilot lit, may very well pale in comparison to what you would spend on repairs of a higher efficient unit. As my personal plumber stated - they all do ONE thing - heat water, so why get technical about it. I just replaced my WH 3 months ago - BW 50 gallon Defender System - direct vent. Why did I choose a BW? I believe in keeping the money that I make here in the US, stays in the US, as Bradford White is based here in the US only - Michigan. :) Good luck with whatever you choose!

Wow... "power direct vent" was a new one for me. I had to look it up. It looks like a power vent (uses fan to exhaust) with a coaxial outside air intake to draw combustion air from outside. Of the two, I would use a power direct vent since it's getting air from outside instead of inside the heated space. The answer to your question about hot water if power goes out is "no". The odd thing is that the efficiency ratings aren't great (.67). Consider a condensing gas tankless for the same amount of money and .92 energy efficiency.

Mechanical Codes require flues or chimney to be resized if appliances are removed and some appliances are left 'orphaned'. It is likely that your home inspector uncovered a Code violation and unsafe condition because of this 'orphaned' water heater. The simplest means to correct the problem is usually to replace the water heater with a new one and have that new water heater direct vented or power vented to the exterior. This should be done at the current owner's expense. Contact your local mechanical code inspector for details.